Does simplification signify compromise? Evaluation of different universal adhesives on shear bond strength

Does simplification signify compromise? 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Evaluation of different universal adhesives on shear bond strength Jiyuan Chen, Yuxin Xiao, Yihang Wei, Xinqi Li, Hidehiko Sano, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8163770/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Universal adhesives are widely used in the field of dental prosthetics owing to their broad applicability and clinical convenience. This study aims to evaluate the bonding performance of four adhesives on zirconia and resin material surfaces. Methods The shear bond strength (SBS) test results of four adhesives including Single Bond Universal Adhesive (3M1), Scotchbond™ Universal Plus Adhesive (3M2), PALFIQUE UNIVERSAL BOND (TK1) and BONDMER Lightless Ⅱ (TK2) were studied under three storage conditions: constant-temperature water storage at 37℃ for 24 h, 5,000 thermal cycles, and 10,000 thermal cycles. Three-way ANOVA, Tukey HSD test, and Games-Howell test were performed on the outcome data (α = 0.05). The Adhesive Remnant Index is used to evaluate the debonding condition between resin and zirconia surfaces. Results All four groups exhibited acceptable bond strength measured at 24 h in a 37℃ constant-temperature water bath and statistically significant differences were observed among the four groups (p<0.05). However, after thermal cycling, the bond strength of all groups showed significant decline, with only TK1 yielding detectable data. Three-way ANOVA results indicated that all factors—storage conditions (p<0.001), brands (p<0.05), and generations (p<0.05)—exerted significant effects on SBS. At the same time, the interaction among the three factors also showed significant statistical difference (p<0.001). Conclusions The bonding performance of universal adhesives of different generations and brands is material-dependent. After 5,000 thermal cycles, the SBS differed significantly among brands and generations of adhesives, with TK1 exhibiting better performance in this study. Technological advances have introduced user-friendly products with simplified application procedures. However, clinicians should adopt an evidence-based perspective and focus on clinical effect and experimental data of materials. shear bond strength (SBS) universal adhesive zirconia resin cement light-less Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Introduction Currently, universal adhesives have been widely applied in clinical treatment of both direct and indirect restorations[ 1 ]. Owing to high mechanical strength and favorable biocompatibility, zirconia ceramic has been extensively adopted in prosthodontics and has been regarded as the first-choice material for dental restorations[ 2 ]. However, with conventional bonding protocols, zirconia exhibits inferior bonding performance to silica-based ceramic on account of its surface inertia and poor reactivity[ 3 ]. Since universal adhesives appeared on the market in 2011, laboratory reports concerning bond strength to zirconia ceramic and silica-based ceramic have revealed: reliable adhesion has been convinced to zirconia ceramic[ 4 ]. But for silica-based ceramic, compared to the combination of hydrofluoric acid and silane coupling agent, bonding property and durability of universal adhesives remain significant potential for improvement[ 5 ]. At present, in the dental market, most universal adhesives are represented by the single-bottle system while there are also two-bottle clinical products that are applied by mixing Bond A and Bond B in equal proportions. Both of the above two forms of universal adhesives belong to 1-step self-etching system[ 6 ]. Single-bottle universal adhesives are light-curable, which is the most common curing mode of adhesives. Camphorquinone[ 7 ] is generally utilized as the initiator and is cured by light irradiation at wave-length of 360–510 nm to initiate the polymerization reaction[ 8 ]. Compared to 2- and 3-step systems, although universal adhesive simplifies the application protocols, light-curing operation still occupies chair-side time and cannot be utilized in areas with limited light access[ 9 ]. The counterpart is a two-bottle, self-curing system with separated incompatible components. Polymerization of the redox-initiated free radicals is only initiated upon blending the two reactive pastes together. Benzoyl peroxide (BPO)/tertiary aromatic amine is most widely utilized as a chemical initiator[ 10 ]. It has been reported that two-bottle universal adhesives provided more durable bonding performance compared with the single-bottle counterparts[ 11 ]. Universal adhesives are acclaimed multifunctional, providing reliable bonding to major dental substrates including enamel, dentin, ceramics, metals and composite resins[ 12 ]. Without preparation of specialized primers for each material, universal adhesives are preferred for optimizing clinical operational procedures and consequently reducing chair-side time[ 6 , 13 ]. Nevertheless, significant limitations remain: the bond strength is sensitive to shelf-life, storage temperature, number of coating layers, light-curing time, temperature and time of air-blowing[ 14 – 18 ]. Meanwhile, technological sensitivity is still included throughout the application process. To improve the technical sensitivity of the product and application procedures, dental material manufacturers are upgrading their clinical products, typically including the following methods: adding or replacing functional ingredients, adjusting the concentration of active ingredients, reducing the strict requirements of materials for storage environments, etc. The redeveloped products often attract clinicians’ attention for their distinguishing features compared to previous generations. However, there is rare literature reports on the actual differences between the earlier and current generation products in various application scenes, as well as the comparison of bond strength between adhesives from different manufacturers under equivalent conditions. Long-term stability of the prosthesis is the primary indicator for evaluating adhesive performance. In current laboratory research, common methods such as constant-temperature water storage and thermal cycling are employed to simulate the temperature variations, component hydrolysis and mechanical stress factors presented in clinical oral environments and during oral functional condition[ 19 – 21 ].The adhesives from Solventum (3M) and Tokuyama (TK) are currently widely used in clinical applications. Therefore, in this study, the earlier generation(generation-1) and current generation (generation-2) of universal adhesives from two brands were selected for in vitro experiments under different storage conditions to evaluate the effects of brand, generation, and storage condition on the bonding performance between zirconia and resin. The null hypotheses were as follows: (1) 3M and TK adhesives exhibit equivalent bonding performance under the same storage condition and generation. (2) Generation-1 and generation-2 adhesives from the same brand show no difference in SBS under identical storage conditions. (3) There is no difference in SBS under different storage conditions for adhesives of the same brand and generation. Methods Bonding agents and resin cylinders CAD/CAM-produced zirconia cube specimens (24 in total, Aidite Technology, Qinhuangdao, China) with a length of 2 cm and resin cylinders (216 in total, Aidite Technology, Qinhuangdao, China) with a base diameter of 2 mm and a surface area of 12.56 mm² were acquired for the study. The 24 zirconia specimens and 216 resin cylinders were randomly divided into 4 groups, corresponding to the bonding agents, with each group containing 6 zirconia specimens and 54 resin cylinders. The resin cylinder specimens and zirconia specimens are illustrated in Fig. 1 . The bonding agents used in this study were as follows: Group 1 (3M1 + RUC): Single Bond Universal Adhesive + RelyX™ Ultimate Clicker Adhesive Resin Cement; Group 2 (3M2 + RUC): Scotchbond™ Universal Plus Adhesive + RelyX™ Ultimate Clicker Adhesive Resin Cement; Group 3 (TK1 + EP): PALFIQUE UNIVERSAL BOND + ESTECEM Plus Universal; Group 4 (TK2 + EP): BONDMER Lightless Ⅱ + ESTECEM Plus Universal The lot number, manufacturers, and detailed chemical composition of the aforementioned bonding agents and the zirconia cleaning paste are presented in Table 1 . Application procedures for each product are detailed in Table 2 . All operations were conducted at room temperature (25 ± 1℃). The curing modes and storage temperature of four universal adhesives selected in this study are demonstrated in Table 3 . Figure 2 . Surface appearance of each universal adhesive applied to zirconia.From left to right: 3M1, 3M2, TK1, TK2; The upper parts of TK1 and TK2 were coated twice. Table 1 The lot number, manufacturers and chemical formulation of the materials used in present study. Code Materials (Lot No.) Manufacturer Chemical Formulation 3M1 Single Bond Universal Adhesive (4075B) 3M Deutschland GmbH 41453 Neuss (Germany) 10-MDP, dimethacrylate resins, HEMA, polyalkenoic acid copolymer, filler, ethanol, water, CQ, γ-MPTS, silane 3M2 Scotchbond Universal Plus Adhesive (10860837) 10-MDP, 4,6-dibromoresorcinol-based dimethacrylate diester, DMAE-B, HEMA, acrylic-itaconic copolymer, filler, ethanol, water, CQ, γ-MPTES, APTES, silica RUC RelyX™ Ultimate Clicker Adhesive Resin Cement (12129322) Base paste: methacrylate monomers, radiopaque, silanated fillers, initiator components, stabilizers, rheological additives Catalyst paste: methacrylate monomers, radiopaque, alkaline (basic) fillers, initiator components, stabilizers, pigments, rheological additives, fluorescence dye, dual-cure activator for single bond universal adhesive TK1 PALFIQUE UNIVERSAL BOND (Bond A:133, Bond B:611) Tokuyama Dental Corp. (Japan) Bond A: 3D-SR monomer, MTU-6, HEMA, Bis-GMA, TEGDMA, acetone, BHT Bond B: γ-MPTES, borate, TMBHP, acetone, isopropyl alcohol, water, BHT TK2 BONDMER Lightless Ⅱ (Bond A:056, Bond B:540) Bond A: phosphate acid, Bis-GMA, MTU-6, HEMA, TEGDMA, acetone Bond B: γ-MPTES,acetone, ethanol, water, borate catalyst, peroxide EP ESTECEM Plus Universal (A087B8) Bis-GMA, TEGDMA, Bis-MPEPP, silica-zirconia filler, CQ, BPO IVO Ivoclean (Z06KJ2) Ivoclar-Vivadent (Liechtenstein) Zirconium oxide, water, polyethylene glycol, sodium hydroxide, pigments, additives 10-MDP, 10-methacryloyloxydecyl dihydrogen phosphate; HEMA, 2-hydroxyethyl methacrylate; γ-MPTS, γ-methacryloxypropyl trimethoxy silane; DMAE-B: dimethylaminoethanol bitartrate; CQ: camphorquinone; γ-MPTES, γ-mercaptopropyl trimethoxysilane; APTES, 3-aminopropyl triethoxysilane; 3D-SR monomer, three dimensional self-reinforcing monomer; MTU-6, 6-methacryloxyhexyl 2-thiouracil-5-carboxylate; Bis-GMA, bisphenol-A-diglycidylmethacrylate; TEGDMA, triethylene glycol dimethacrylate; BHT, butylated hydroxytoluene ; TMBHP, tert-butyl hydroperoxide; BPO, benzoyl peroxide Table 2 Application procedures of the bonding agents and cleaning paste used in present study. Code Application procedures 3M1 1. Apply the adhesive to the zirconia surface and resin cylinders base 2. Gently blow dry the adhesive for 15 s to a thin uniform coat 3. Light cure for 20 s 3M2 1. Apply the adhesive to the zirconia surface and resin cylinders base 2. Gently blow dry the adhesive for 15 s to a thin uniform coat 3. Light cure for 20 s TK1 1. Apply 1 drop of liquid A and liquid B into mixing plate. Gently mix A and B together 2. Apply the TK1 mixture to the zirconia surface and resin cylinders base respectively 3. Gently air-blow dry the adhesive for 15 s to a thin uniform coat TK2 1. Apply 1 drop of liquid A and liquid B into mixing plate. Gently mix A and B together until the adhesive turns a uniform green 2. Apply the TK2 mixture to the zirconia surface and resin cylinders base respectively 3. Gently air-blow dry the adhesive for 15 s to a thin uniform coat RUC 1. Apply appropriate amount of base paste to the resin cylinders base with syringe 2. Immediately after applying adhesive, lightly place the resin cylinder onto zirconia surface 3.Remove excess cement and light cure for 20 s on each side of the resin cylinder at a distance of approximately 5 mm from the surface EP 1. Apply appropriate amount paste to the resin cylinders base 2. Gently blow dry the cement for 15 s to a thin uniform coat, lightly place the resin cylinder onto zirconia surface 3. Remove excess cement within 1 to 3.5 minutes. IVO 1. Cover the entire bonding surface of zirconia with a layer of Ivoclean using a microbrush or bush. 2. Allow 20 seconds for the cleaning action of Ivoclean to take effect 3. Thoroughly rinse with water spray and dry with oil-free air. Table 3 Curing modes and storage temperature of the four types of universal adhesives Universal adhesive Curing mode Storage temperature 3M1 light-cure 2–25℃ 3M2 light-cure 2–25℃ TK1 self-cure 0–10℃, keep refrigerated and sit until it reaches room temperature before opening. TK2 self-cure 0–25℃ Surface preparation The bonding surfaces of zirconia cubes were treated by sandblasting with 125 µm aluminum oxide particles for 60 s at a distance of 10 mm, an angle of 90°, and a pressure of 2.8 bar. Following sandblasting, the bonding surfaces of all zirconia specimens were placed face-down and underwent ultrasonic cleaning in distilled water for 5 min and gentle air-blowing for 15 s subsequently. The application of IVO followed the manufacturer’s instruction: it was applied to the prepared zirconia surface for 60 s, followed by rinsing with distilled water for 15 s and gentle air-blowing. Application procedure The resin cylinders were bonded to the zirconia surfaces using a consistent clamp, ensuring that the same pressure (10 N) was applied across all groups. Excess resin cement surrounding the bonding interface was carefully removed using a small brush, taking care not to move or disturb the bonding interface. The procedures for light curing (Kerr Demi Plus, Orange, CA, United States) and the resin cement bonding were described in detail in Table 2 . A diagram of the bonding of the resin cylinders to the zirconia surface is shown in Fig. 3 . Shear bond strength (SBS) test The resin cylinder specimens bonded with each bonding agent were further divided into three subgroups, with 18 resin cylinder specimens in each subgroup. The three subgroups were assigned to different storage conditions: storage in distilled water at 37℃ for 24 h, 5,000 cycles of thermal cycling, and 10,000 cycles of thermal cycling, respectively. One-third of the resin specimens were tested after storing in an incubator (Shanghai Lichen Bangxi Instrument Technology Co., Ltd., China) with distilled water at 37℃ for 24 h. The remaining specimens underwent thermal cycling in a thermocycler (THE 1400, SD Mechatronik, Germany): one-third underwent 5,000 cycles of thermal cycling between 5℃ and 55℃, with a dwell time of 25 s per bath and a transfer time of 10 s. One-third underwent 10,000 cycles of thermal cycling between 5℃ and 55℃, with a dwell time of 25 s per bath and a transfer time of 10 s. The SBS test was conducted using a universal testing machine (WD-200 Weidu, Wenzhou, China) with a crosshead speed of 1 mm/min (Fig. 3 ) .The SBS formula used was P(MPa) = F(N)/S(mm 2 ). Out of 18 results in each group, the highest 4 and lowest 4 data points were discarded, and the remaining 10 were considered for analysis (n = 10). Adhesive remnant index (ARI) score The ARI scoring was based on digital photographs with the help of a dental digital camera (EyeSpecial C-IV, Shofu, Kyoto, Japan). Following the SBS test, the bonding surfaces of the zirconia and resin specimens were observed. The ARI failure mode was represented by a scale with 5 levels (Score A to Score E) as follows: Score A: Almost no cement or adhesive remained on the zirconia surface (0%); Score B: 1% − 49% of the cement and adhesive remained on the zirconia surface; Score C: 50% − 99% of the cement and adhesive remained on the zirconia surface; Score D: Almost all the cement and adhesive remained on the zirconia surface (100%); Score E: The adhesive layer fractured cohesively within the material, leaving remnants on both the zirconia and resin cylinder surfaces. The ARI scoring criteria designated in the present study are shown in Fig. 4 . To minimize error, the images were scored independently by three calibrated examiners. In cases of disagreement for each specimen, a majority opinion was adopted. Statistical analysis Out of 18 results in each group, the highest four and lowest four data points were discarded, and the remaining 10 were considered for analysis (n = 10). The three-way ANOVA (brands, generations and storage conditions) was used to analyze the influence of these factors on the results. Additionally, multiple comparisons were performed for all groups using either the Tukey HSD test or the Games-Howell test, depending on the homogeneity of variance assumption. This analysis was conducted using SPSS version 27.0, with a significance level of α = 0.05. Surface evaluation Resin cylinder surfaces after debonding were examined with a field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectrometry (EDS; Phenom Pharos G2, Netherlands) to determine elemental composition and distribution. Results Shear bond strength (SBS) The mean values and standard deviation for each group are summarized in Table 4 and Fig. 5 . The SBS intergroup differences measured for the four groups 3M1, 3M2, TK1, and TK2 under a 24 h, 37℃ constant-temperature water storage were significant (p<0.05).3M2 and TK1 exhibited stronger adhesive strength, significantly higher than that of 3M2 and TK1. After 24 h water storage, the bond strengths of the four adhesives were respectively as follows: 3M2, TK1, TK2, and 3M1. Compared to 3M1, 3M2 exhibited significantly higher immediate bond strength (p0.05). After 5,000 and 10,000 thermal cycles, the bond strength of all groups showed significant degradation. Solely TK1 can be detected, while the others registered null values. Especially after 5,000 thermal cycles, TK1 still performed well. After 10,000 thermal cycles, although no statistically significant differences were observed in SBS of the four adhesives, which meant the differences were negligible, TK1 still yielded detectable SBS data in the testing machine (p>0.05). Table 4 SBS values (MPa) for four bonding agents in three different storage conditions (mean ± SD). Storage condition 3M1 3M2 TK1 TK2 24 h 4.86 ± 0.49 1,a 6.99 ± 1.94 1,b 6.10 ± 0.89 1,b 4.98 ± 1.16 1,a,b 5,000 cycles 0 2,a 0 2,a 2.96 ± 1.052 2,b 0 2,a 10,000 cycles 0 2,a 0 2,a 0.16 ± 0.27 3,a 0 2,a The same numbers indicate no significant differences in SBS within the same bonding agent under different storage conditions (p > 0.05). The same lowercase letters indicate no significant differences in SBS among different bonding agents under the same storage condition (p > 0.05). Three-way ANOVA results (Table 5 ) revealed that storage conditions (p<0.001, F = 627.488), brands (p<0.05, F = 7.528), and generations (p<0.05, F = 6.106) all significantly influenced SBS. Statistically significant interactions were found between three factors: Storage conditions * Brands (p<0.001, F = 15.410), Storage conditions * Generations (p<0.001, F = 16.970), and Brands * Generations (p<0.001, F = 55.095). Furthermore, notably, the interaction among the three factors—Storage conditions, Brands, and Generations—also demonstrated statistical significance (p<0.001, F = 11.807). Table 5 Three-way ANOVA results of all bonding agents in different storage conditions. Source df Mean square F p Corrected model 11 78.811 128.371 <0.001 Intercept 1 565.806 921.607 <0.001 Storage conditions 2 385.236 627.488 <0.001 Brands 1 4.622 7.528 0.007 Generations 1 3.749 6.106 0.015 Storage conditions * Brands 2 9.461 15.410 <0.001 Storage conditions * Generations 2 10.418 16.970 <0.001 Brands * Generations 1 33.825 55.095 <0.001 Storage conditions * Brands* Generations 2 7.429 11.807 <0.001 Table 6 , 7 , 8 demonstrated the results of Games-Howell test and Tukey HSD test. Table 6 indicated that both the 3M and TK adhesives demonstrate significantly superior performance under 24 h water storage compared to 5,000 and 10,000 thermal cycles later. Under 24 h water storage, 3M was slightly higher than TK, but the difference was not statistically significant. After 5,000 thermal cycles, the 3M group totally debonded, while the TK group retained certain adhesive strength, with statistically significant difference existing between two groups (p0.05), though measurable values remained detectable in the TK group. Table 6 The mean SBS values (MPa) the two bonding agent brands (mean ± SD). Storage condition 3M TK 24 h 5.93 ± 1.76 1,a 5.54 ± 1.16 1,a 5,000 cycles 0.00 ± 0.00 2,a 1.48 ± 1.68 2,b 10,000 cycles 0.00 ± 0.00 2,a 0.08 ± 0.20 3,a The same numbers indicate no significant differences in SBS within the same bonding agent under different storage conditions (p > 0.05). The same lowercase letters indicate no significant differences in SBS among different bonding agents under the same storage condition (p > 0.05). SBS of both generation-1 and generation-2 adhesives decreased significantly after 5,000 thermal cycles compared to the SBS under 24 h of 37℃ water storage (Table 7 ). The SBS of generation-1 adhesives was consistently detectable, even remained significantly higher than that of the generation-2 adhesives (p<0.05) post 5,000 thermal cycles, primarily attributed to TK1. After 10,000 thermal cycles, both groups become virtually ineffective. Table 7 The mean SBS values (MPa) of the two bonding agent generations (mean ± SD). Storage condition Generation1 Generation2 24 h 5.48 ± 0.95 1,a 5.98 ± 1.87 1,a 5,000 cycles 1.48 ± 1.68 2,a 0.00 ± 0.00 2,b 10,000 cycles 0.08 ± 0.20 3,a 0.00 ± 0.00 2,a The same numbers indicate no significant differences in SBS within the same group under different storage conditions (p>0.05). The same lowercase letters indicate no significant differences in SBS among different brands under the same storage condition (p>0.05). Integrating the three storage conditions, the SBS ranked respectively as TK1, 3M2, TK2, and 3M1. However, no statistical differences (Table 8 , p>0.05) were observed among the four adhesives. SBS value of TK1 demonstrated 3.08 ± 2.59 MPa, slightly higher than the three other bonding agents, attributed to TK1's superior performance compared to the other groups post thermal cycling. Table 8 The mean SBS values (MPa) of the four bonding agent types (mean ± SD). Generation 3M TK generation1 1.62 ± 2.35 1,a 3.08 ± 2.59 1,a generation2 2.33 ± 3.52 1,a 1.66 ± 2.47 1,a The same numbers indicate no significant differences in SBS within the same group under different storage conditions (p > 0.05). The same lowercase letters indicate no significant differences in SBS among different brands under the same storage condition (p > 0.05). Failure modes The ARI scores for the four adhesives are shown in Table 9 and Fig. 6 . The two 3M products both exhibited a strong trend to Mode A under all three storage conditions. 3M1 remained at A under all conditions, while 3M2 completely degraded from B to A after thermal cycling. In contrast, TK products performed three distinct modes—C, D, and E—under 24 h conditions. TK1 concentrated in E within 24 h, and as the number of thermal cycling increased, it decreased from C and D to concentration in A and B. TK2 showed a similar trend: the initial dispersion of results across score B, C, D, and E gradually diminished, ultimately concentrating in categories A and B post thermal cycling. Table 9 ARI scores of each group with different bonding agents bonded to zirconia. Group tested (24 h/5,000 cycles/10,000 cycles) ARI scores A B C D E 3M1 10/10/10 0/0/0 0/0/0 0/0/0 0/0/0 3M2 6/10/10 4/0/0 0/0/0 0/0/0 0/0/0 TK1 0/0/4 0/0/6 1/4/0 0/5/0 9/1/0 TK2 0/4/8 1/6/2 2/0/0 4/0/0 3/0/0 Surface characterization In this study, the specimens after 5,000 thermal cycles in each group were selected for SEM image acquisition and elemental analysis. Air bubbles in the adhesives could be observed on the surfaces of debonded resin cylinders in groups 3M1, 3M2 and TK2 (Fig. 7 ). The elemental composition and distribution of carbon(C), oxygen(O) and silicon(Si) on the surface of four groups of resin cylinders were shown in Fig. 8 . Discussion Comparison of bonding agents This study was aimed at evaluating the impacts of adhesives under different storage conditions, from various brands and of two generations on the bonding performance between zirconia ceramics and resin. According to Table 6 , the bond strength of TK adhesive after 5,000 thermal cycles was statistically significantly higher than that of failed 3M specimens (p<0.05) whereas no significant differences in bond strength were observed under other storage conditions. Therefore, the null hypothesis that 3M and TK adhesives exhibit equivalent bonding performance under the same storage condition and generation could be partially rejected by these outcomes. As detailed in Table 7 , the first-generation adhesives displayed significantly higher in SBS compared to failed second-generation specimens after 5,000 thermal cycles (p<0.05), indicating the intergenerational influence on bonding efficiency. This intergenerational influence manifested exclusively in part of the outcomes, partially rejecting the null hypothesis that generation-1 and generation-2 adhesives from the same brand show no difference in SBS under identical storage conditions. Influence of solvent components Table 4 demonstrated SBS of four adhesives from various brands and generations under different storage conditions. Unexpectedly, only TK1 exhibited significantly higher SBS than other debonded counterparts(p<0.05).After 10,000 thermal cycles, TK1 remained detectable values, though decaying to levels showing no statistical difference from other groups. Therefore, from a statistical perspective combining both bonding strength and durability, TK1 showes superior adhesive property among the four groups. Water and organic solvent are both indispensable/imperative components of adhesives. Organic solvent acts as carriers of the monomers into the collagen interfibrillar spaces[ 22 ]. And water is added to trigger the ionization of the respective phosphate monomer[ 23 ].While within the bonding interface, enhanced bonding strength is associated with lower concentration and hydrophilicity of solvent[ 24 ]. Hydrolysis is considered as the main reason for bonding failure. Residual solvent was found to inhibit the polymerization of resin and induce deterioration of hybrid layer, thus damage the clinical performance of adhesives[ 25 , 26 ]. Since composition and concentration of solvent are critical determinants for adhesive bonding strength[ 27 ], air-blowing is generally executed in clinical practice to accelerate volatilization and thus decrease extent of solvent within the bonding interface. Ethanol and isopropanol are both hydrophilic monomers. When employed as solvents, they could aid in the wetting of dentin matrix, the diffusion of resin monomers in collagen network, the replacement of water from the dentin surface and provide dry bonding environment[ 28 ]. Content of hydrophilic monomers demonstrated a positive correlation with water absorption of resin polymer network. If hydrophilic monomers were not removed adequately by air-blowing, water absorption of the network would increase, resulting in degradation of the adhesive layer. Furthermore, after penetrating the polymer resin chains, the hydrophilic molecules acted as plasticizers to cause expansion of the network and reduced the friction between polymer chains, softening the material[ 29 ]. In this experiment, TK1 exhibited relatively better SBS than TK2 (Table 4 ). Compared to the refrigeration-requiring TK1, TK2 is allowed to be stored at room temperature (2–25℃) and with the replacement of solvent composition from isopropanol to ethanol with increase in concentration (from 10%-30% to 25%-35%). Ethanol has a lower boiling point than isopropanol and is therefore more volatile at room temperature[ 30 ]. Sceptically, the adjustment of solvent concentration and type might expedite the evaporation of solvent under identical air-blowing step, contributing to the difference in thickness and trait of the adhesive layer between TK1 and TK2 (Fig. 2 ). Researches have reported that surface heterogeneity[ 31 ] and excessive thickness[ 32 ] of the bonding layer will result in decrease in adhesion force. Furthermore, if room temperature preservation led to partial evaporation of ethanol requires further validation. Performance of silane Table 4 demonstrated that 3M2 exhibited significantly higher immediate SBS than 3M1 (p<0.05). 3M officially claims that when used alone, 3M2 exhibited advanced bonding to glass-ceramics, reaching the gold standard level of traditional, separate silanes. This breakthrough is attributed to the modified silane coupling agents in 3M2 components. The siliane coupling agent contained in 3M1 is γ-MPTS, and the inorganic phase is vitreous silica. 3M2 included the modified organic silane components[ 33 ]. γ-MPTES and APTES were used as siliane coupling agents and the inorganic phase was synthetic amorphous silica. It is suspected that γ-MPTES and APTES of 3M2 co-hydrolyzed in solvent and condensed with silica to form siloxane bond (Si-O-Si), generating a thick hybrid silane layer[ 34 , 35 ]. Meanwhile, basic amino groups are generated, neutralizing excess acidic monomers and bonding with resin to enhance the connection between siliane and resin, which is consistent with prior findings[ 36 ]. Furthermore, γ-MPTES reduced the surface tension of the adhesive, which increased the wettability of the adhesive to zirconia surface and thus improved the bonding performance[ 37 ]. In addition, APTES could also react with organic compounds such as epoxy resin to silanize them, increasing bonding strength between the adhesive and inorganic ingredients[ 38 ]. The difference between single-bottle and two-bottle universal adhesives Single-bottle adhesives are generally light-cure system, and two-bottle bonding agents mainly belong to self-cure system. To meet a variety of requirements, single-bottle adhesives pack all chemical ingredients in a single bottle of agent. Long-term storage in acidic condition for silane coupling agents lead to emergence of hydrolysis, dehydration and condensation, forming oligomers that cannot bond to glass ceramics. Meantime, acidic functional monomers also undergo hydrolysis reactions, further affecting bonding performance[ 39 ]. Extra addition of silane coupling agent is necessary for potent bonding to ceramic materials. Material deterioration is avoided fundamentally in two-bottle system by physically isolating incompatible chemical components into two containers[ 40 ], such as segregating silane coupling agents and acidic functional monomers to enhance effective adhesion to ceramics[ 41 ]. Adhesives from TK brand demonstrated higher SBS than products from 3M post thermal cycling (Table 6 ). Among the four adhesives adopted in this study, 3M1 and 3M2 were classified as single-bottle, light-curable adhesives, while TK1 and TK2 belonged to two-bottle, self-cure system. The borate and peroxide included in TK1 and TK2 constituted potent chemical polymerization initiator. The borate catalyst reacted with acidic three-dimensional self-reinforcing (3D-SR) monomers to form boron compounds. The compounds then were oxidized by acidic monomers and generated highly active initiators for chemical polymerization[ 42 ]. It has been reported that adhesives including borate initiators displayed higher monomer conversion rate than camphorquinone based light-cure adhesives[ 43 ], in line with the present study. Speculation has been drawn that the outstanding performance of TK post thermal cycling was attributed to the stability of the initiator and the high monomer conversion rate it generated. Additionally, 3M2 displayed slightly higher SBS than TK1 after 24 h water bath (Table 4 ). Nevertheless, a distinct difference in failure mode of these two groups were observed in Table 8 : For 3M2, most adhesive and cement remained in resin surfaces while the cohesive fracture occurred in TK1 on account of exceptional adhesion to both zirconia and resin surface. It is speculated that the diversified composition of these two adhesives determined divergent material property and consequently accounted for the discrepancy in failure mode. Effect of storage conditions Thermal stress and hydrolysis induced by thermal cycling between 5°C and 55°C stimulated the effect of intraoral temperature changes. 10,000 cycles represented approximately one year of oral functional status in clinical practice, while 5,000 cycles stood for six months[ 44 ]. SBS declined significantly post thermal cycling (p<0.05). After 5,000 cycles, all four groups showed significant attenuation, and almost completely debonded after 10,000 cycles (Table 4 ).These results were consistent with previous study[ 45 ]. Therefore, rejecting the null hypothesis: (3) There is no difference in SBS under different storage conditions for adhesives the same brand and generation. It is speculated that the rapid decline in SBS post thermal cycling was related to the HEMA component contained in all four adhesives (Table 1 ). HEMA is a highly hydrophilic functional monomer, which can reduce the viscosity of resin to form a more uniform bonding layer, promote resin infiltration and penetration into the base tooth dentin and improve the water absorption of deeper dentin[ 46 , 47 ]. However, akin to what previous researches have demonstrated, HEMA could decrease the conversion degree of monomers[ 48 , 49 ] and impact long-term bonding performance due to the water absorption and adhesive interface hydrolysis caused by its hydrophilia[ 50 ]. Explanation of failure modes All four universal adhesives selected for this study contained components containing Si elements. After 5,000 thermocycles, air bubbles were observed on the surface of debonding resin cylinders in groups 3M1, 3M2 and TK2 due to solvent evaporation in the adhesive, while there were no bubbles on the surface of resin cylinders in group TK1 and the control group (Fig. 7 ). Moreover, on the specimen surfaces, only TK1 and the control group failed to be detected containing the Si element, while Si in the residual adhesives on the surface were detected in the other 3 groups. It is indicated that for most specimens in the TK1 group after 5,000 thermal cycles, the adhesive layer remained on the surface of zirconia cubes, which is consistent with the fracture mode results observed in Table 9 . Adhesives of two brands exhibited completely different failure modes. Two types of adhesives of 3M showed the trend to remain on the resin surface while almost no residue on the zirconia surface, particularly post thermal cycling. On the other hand, adhesives from TK tended to remain on the zirconia surface. And surprisingly, there was a phenomenon where the adhesive was scattered both on the resin and zirconia surface (Table 9 ), namely cohesive failure of adhesives, which belonged to the fracture occurring inside the adhesive layer[ 51 , 52 ]. Yuta Tsuji analyzed the failure mode of epoxy-hydroxylated layer, supposing the interfacial failure and cohesive failure were competing with each other. When the maximum force required for interfacial failure exceeded the maximum force for cohesive failure, cohesive failure occurred. Otherwise, the interfacial failure occurred[ 53 ]. Similarly, it is speculated that when the chemical interaction on the interface is sufficient, fractures are forced to occurred inside the bonding layer, resulting in the cohesive failure of TK adhesives. Consideration of chair-side convenience and clinical bonding performance The four universal adhesives selected in this study have certain differences in curing modes and storage temperature variations, representing varying degrees of clinical convenience, as shown in Table 3 . TK1 is a self-cure adhesive without light-cure step, simplifying the chair-side procedures. But its obligatory requirement of refrigerated storage increases the complexity of material storage to a certain extent. TK2 changes the storage conditions to room temperature with non-essential light-cure step, which is more clinically convenient among the four groups. In contrast, the two universal adhesives from 3M company both require the light-cure step, owning the same operational procedures of All-in-1 system. The evaluation of dental adhesive material is increasingly oriented toward streamlining operational procedures, mitigating technological sensitivity and reducing chair-side time. Nevertheless, simplification and novelty should not be achieved at the expense of/compromise material properties[ 54 ]. In the context of porcelain veneer cementation, clinicians maintain elevated psychological expectations regarding bonding efficacy achieved through complicated adhesive protocols. Whereas occasionally adequate retention forms afford robust guarantee for prosthetic retention. As auxiliary force for retention, adhesion is permitted a certain degree of compromise in its strength. Consequently, luting products with simplified procedures exemplified self-adhesive resin cement have come out in response to clinical needs. The Tokuyama corporation incorporated a novel initiator system to omit the light-cure process of the conventional “applying—air-blowing—light-curing” protocol. One of the distinctions between the two generations lies in the broadened storage temperature range of TK2, with no more requirement for refrigeration. Refrigerated storage is necessary to preserve efficacy of resin-based products[ 55 ], especially in summer or in regions of elevated ambient temperature. As demonstrated in Table 3 , it is evident that TK1 revealed higher SBS among all groups under different storage conditions. While TK2, without refrigeration, exhibited slightly weaker SBS post thermal cycling, seemingly indicating in this experiment the simplification of operation made concessions in terms of bonding strength. However, 3M adhesives with more complex chair-side operation contrarily showed weaker SBS than TK1 post thermal cycling (Table 8 ), manifesting that application complexity could not define the adhesive property of materials, which were not contradictory. Though, TK1 is a two-bottle adhesive, thorough mixing is needed before application to the surface. In the future, the development target for ideal clinical products should be of simple operational steps and wide temperature adaption range, meanwhile still providing sufficiently strong bond strength, thereby achieving real simple but not simplistic clinical application. Discussion limitations This in vitro study simulated oral functional condition via thermal cycling, lacking actual temperature of oral cavity and salivary immersion of specimens. Surface treatment solely encompassed sandblasting and cleaning of zirconia and resin cylinder bonding surface, without exploration of zirconia surface modification. Smooth and flat zirconia ceramic surfaces were employed as bonding interfaces in this study. Subsequent researches should include evaluation of various surface treatment methods of zirconia and explore in depth the best-matched pretreatment for each bonding agents, hereby to render instruction for clinical decisions. Conclusion 1. The bond strength of universal adhesives of different generations and brands is material-dependent. 2. After 5,000 thermal cycles, the SBS differed significantly among brands and generations of adhesives, with TK1 exhibiting better performance in this study. 3. Technological advances have introduced user-friendly products with simplified application procedures. However, clinicians should adopt an evidence-based perspective and focus on clinical effect and experimental data of materials. Abbreviations 3M1 Single Bond Universal Adhesive 3M2 Scotchbond™ Universal Plus Adhesive TK1 PALFIQUE UNIVERSAL BOND TK2 BONDMER Lightless Ⅱ 3M Minnesota Mining and Manufacturing TK Tokuyama Three-way ANOVA Three-way Repeated Measures Anova HSD Honestly Significant Difference SBS Shear Bond Strength BPO Benzoyl peroxide CAD/CAM Computer-Aided Design/Computer-Aided Manufacturing RUC RelyX™ Ultimate Clicker Adhesive Resin Cement EP ESTECEM Plus Universal IVO Ivoclean 10-MDP 10-methacryloyloxydecyl dihydrogen phosphate HEMA 2-hydroxyethyl methacrylate γ-MPTS γ-methacryloxypropyl trimethoxy silane DMAE-B dimethylaminoethanol bitartrate CQ camphorquinone γ-MPTES γ-mercaptopropyl trimethoxysilane APTES 3-aminopropyl triethoxysilane 3D-SR monomer three dimensional self-reinforcing monomer MTU-6 6-methacryloxyhexyl 2-thiouracil-5-carboxylate Bis-GMA bisphenol-A-diglycidylmethacrylate TEGDMA triethylene glycol dimethacrylate BHT butylated hydroxytoluene TMBHP tert-butyl hydroperoxide THE Thermocycler MPa Megapascal N Newton mm 2 square millimeter ARI Adhesive remnant index FE-SEM field emission scanning electron microscopy EDS Energy Dispersive Spectroscopy SD Standard Deviation SEM scanning electron microscope Declarations Declarations Ethics approval and consent to participate All procedures in this study complied with the relevant guidelines and regulations, including the Helsinki Declaration. Consent for publication Not applicable. Clinical trial number Not applicable. This study is a laboratory-based investigation and does not involve a clinical trial. Therefore, no clinical trial number has been assigned. Competing interests The authors declare no competing interests. Footnotes Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Funding Liaoning Provincial Joint Science and Technology Program (Natural Science Foundation - General Program), Project Number: 2025-MSLH-743 Author Contribution Protocol design: JF, JC, YK; Experiments performance: JC; Data acquisition: JC, YX; Data analysis: JC; Drafted the manuscript: JC, YX, YW, XL, HS; Figure preparation: YX, YW; Revision of manuscript: JF, YK, HS; All the authors have read and approved the final manuscript. Acknowledgments Not applicable. 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The Effect of Expiration Date on Mechanical Properties of Resin Composites. J Int Soc Prev Community Dent. 2018;8(2):99–103. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8163770","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":562491410,"identity":"42c3e366-71f5-4e72-8bb9-1910b153e71d","order_by":0,"name":"Jiyuan Chen","email":"","orcid":"","institution":"School and Hospital of Stomatology, China Medical University","correspondingAuthor":false,"prefix":"","firstName":"Jiyuan","middleName":"","lastName":"Chen","suffix":""},{"id":562491411,"identity":"6b56b6d1-af2c-497f-adf9-cb1c30830611","order_by":1,"name":"Yuxin Xiao","email":"","orcid":"","institution":"School and Hospital of Stomatology, 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17:26:14","extension":"html","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":174028,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8163770/v1/f5396963953f3cf90b9480b6.html"},{"id":98635539,"identity":"150a0547-21f8-425b-a01c-c0ffdf6893bb","added_by":"auto","created_at":"2025-12-19 17:26:16","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":82622,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eIllustration of the resin cylinder specimens and zirconia specimens. (A) Side-view of the resin cylinder; (B) Bottom-view of the resin cylinder; (C) Side-view of the ziconica cube.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8163770/v1/d28fb6e39a60fe113d1b6ec3.jpg"},{"id":98635814,"identity":"599c87f9-5b22-4327-a815-c44f09c60831","added_by":"auto","created_at":"2025-12-19 17:26:35","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":50907,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSurface appearance of each universal adhesive applied to zirconia.From left to right: 3M1, 3M2, TK1, TK2; The upper parts of TK1 and TK2 were coated twice.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8163770/v1/0af9840c88ec1b13da5e0bcb.jpg"},{"id":98635495,"identity":"793eb5c3-7317-4d00-be8d-2e3332d9e318","added_by":"auto","created_at":"2025-12-19 17:26:14","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":46466,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDiagram of specimen setting for SBS test.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8163770/v1/1f74f036d7e728b104348b1f.png"},{"id":98635788,"identity":"40a91d24-56b4-406f-bf9e-16c3fcedc997","added_by":"auto","created_at":"2025-12-19 17:26:29","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":724005,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe ARI scores. (A): score A 0% on zirconia surface; (B): score B 1%-49% on zirconia surface; (C): score C 50%-99% on zirconia surface; (D): score D 100% on zirconia surface; (E): score E on both the zirconia and resin bonding surfaces; Zr: Zirconia; Rc: Resin Cylinder; AL: Adhesive Layer, RC: Resin Cement.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8163770/v1/3b1a3e0ff9224cef35405cf2.png"},{"id":98635730,"identity":"70e1528b-60b7-42a0-a53c-5750a0af9ace","added_by":"auto","created_at":"2025-12-19 17:26:28","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":26612,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSBS values (MPa) for bonding agents under three different storage conditions (mean±SD).\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-8163770/v1/7a608c22c43d6072350a431a.png"},{"id":98635798,"identity":"0ba79661-d237-4806-84a7-2138a7138bb1","added_by":"auto","created_at":"2025-12-19 17:26:30","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":60075,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePercentages (%) of the different failure modes after SBS test of resin cylinders. A to E correspond to Score A to Score E.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-8163770/v1/ca14c2e913fa5d136f5e991c.png"},{"id":98635767,"identity":"a22b6841-c4b5-4077-91bb-42c3a8ba4aa2","added_by":"auto","created_at":"2025-12-19 17:26:28","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":448357,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSEM photographs (1,000×original magnification) of resin cylinder surfaces. GC indicates control group.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-8163770/v1/2c6504849043d37a40e49814.png"},{"id":98635863,"identity":"a39558ff-e880-478a-ac6b-63cd5773c8ab","added_by":"auto","created_at":"2025-12-19 17:26:37","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":895102,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDistribution of elemental composition on the debonding surfaces of resin cylinders. NA indicates no applicable. GC indicates control group.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-8163770/v1/9ade5d37009e65ce571e6739.png"},{"id":100754095,"identity":"1463048b-fb4a-4e40-abbe-47a6a8e2c336","added_by":"auto","created_at":"2026-01-21 05:51:33","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4062455,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8163770/v1/9c676771-2933-46bc-99fc-da71444f2acc.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Does simplification signify compromise? Evaluation of different universal adhesives on shear bond strength","fulltext":[{"header":"Introduction","content":"\u003cp\u003eCurrently, universal adhesives have been widely applied in clinical treatment of both direct and indirect restorations[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Owing to high mechanical strength and favorable biocompatibility, zirconia ceramic has been extensively adopted in prosthodontics and has been regarded as the first-choice material for dental restorations[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. However, with conventional bonding protocols, zirconia exhibits inferior bonding performance to silica-based ceramic on account of its surface inertia and poor reactivity[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Since universal adhesives appeared on the market in 2011, laboratory reports concerning bond strength to zirconia ceramic and silica-based ceramic have revealed: reliable adhesion has been convinced to zirconia ceramic[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. But for silica-based ceramic, compared to the combination of hydrofluoric acid and silane coupling agent, bonding property and durability of universal adhesives remain significant potential for improvement[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAt present, in the dental market, most universal adhesives are represented by the single-bottle system while there are also two-bottle clinical products that are applied by mixing Bond A and Bond B in equal proportions. Both of the above two forms of universal adhesives belong to 1-step self-etching system[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Single-bottle universal adhesives are light-curable, which is the most common curing mode of adhesives. Camphorquinone[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] is generally utilized as the initiator and is cured by light irradiation at wave-length of 360\u0026ndash;510 nm to initiate the polymerization reaction[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Compared to 2- and 3-step systems, although universal adhesive simplifies the application protocols, light-curing operation still occupies chair-side time and cannot be utilized in areas with limited light access[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The counterpart is a two-bottle, self-curing system with separated incompatible components. Polymerization of the redox-initiated free radicals is only initiated upon blending the two reactive pastes together. Benzoyl peroxide (BPO)/tertiary aromatic amine is most widely utilized as a chemical initiator[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. It has been reported that two-bottle universal adhesives provided more durable bonding performance compared with the single-bottle counterparts[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eUniversal adhesives are acclaimed multifunctional, providing reliable bonding to major dental substrates including enamel, dentin, ceramics, metals and composite resins[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Without preparation of specialized primers for each material, universal adhesives are preferred for optimizing clinical operational procedures and consequently reducing chair-side time[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Nevertheless, significant limitations remain: the bond strength is sensitive to shelf-life, storage temperature, number of coating layers, light-curing time, temperature and time of air-blowing[\u003cspan additionalcitationids=\"CR15 CR16 CR17\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Meanwhile, technological sensitivity is still included throughout the application process.\u003c/p\u003e \u003cp\u003eTo improve the technical sensitivity of the product and application procedures, dental material manufacturers are upgrading their clinical products, typically including the following methods: adding or replacing functional ingredients, adjusting the concentration of active ingredients, reducing the strict requirements of materials for storage environments, etc. The redeveloped products often attract clinicians\u0026rsquo; attention for their distinguishing features compared to previous generations. However, there is rare literature reports on the actual differences between the earlier and current generation products in various application scenes, as well as the comparison of bond strength between adhesives from different manufacturers under equivalent conditions.\u003c/p\u003e \u003cp\u003eLong-term stability of the prosthesis is the primary indicator for evaluating adhesive performance. In current laboratory research, common methods such as constant-temperature water storage and thermal cycling are employed to simulate the temperature variations, component hydrolysis and mechanical stress factors presented in clinical oral environments and during oral functional condition[\u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].The adhesives from Solventum (3M) and Tokuyama (TK) are currently widely used in clinical applications. Therefore, in this study, the earlier generation(generation-1) and current generation (generation-2) of universal adhesives from two brands were selected for in vitro experiments under different storage conditions to evaluate the effects of brand, generation, and storage condition on the bonding performance between zirconia and resin.\u003c/p\u003e \u003cp\u003eThe null hypotheses were as follows: (1) 3M and TK adhesives exhibit equivalent bonding performance under the same storage condition and generation. (2) Generation-1 and generation-2 adhesives from the same brand show no difference in SBS under identical storage conditions. (3) There is no difference in SBS under different storage conditions for adhesives of the same brand and generation.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eBonding agents and resin cylinders\u003c/h2\u003e \u003cp\u003eCAD/CAM-produced zirconia cube specimens (24 in total, Aidite Technology, Qinhuangdao, China) with a length of 2 cm and resin cylinders (216 in total, Aidite Technology, Qinhuangdao, China) with a base diameter of 2 mm and a surface area of 12.56 mm\u0026sup2; were acquired for the study. The 24 zirconia specimens and 216 resin cylinders were randomly divided into 4 groups, corresponding to the bonding agents, with each group containing 6 zirconia specimens and 54 resin cylinders. The resin cylinder specimens and zirconia specimens are illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe bonding agents used in this study were as follows:\u003c/p\u003e \u003cp\u003eGroup 1 (3M1\u0026thinsp;+\u0026thinsp;RUC): Single Bond Universal Adhesive\u0026thinsp;+\u0026thinsp;RelyX\u0026trade; Ultimate Clicker Adhesive Resin Cement;\u003c/p\u003e \u003cp\u003eGroup 2 (3M2\u0026thinsp;+\u0026thinsp;RUC): Scotchbond\u0026trade; Universal Plus Adhesive\u0026thinsp;+\u0026thinsp;RelyX\u0026trade; Ultimate Clicker Adhesive Resin Cement;\u003c/p\u003e \u003cp\u003eGroup 3 (TK1\u0026thinsp;+\u0026thinsp;EP): PALFIQUE UNIVERSAL BOND\u0026thinsp;+\u0026thinsp;ESTECEM Plus Universal;\u003c/p\u003e \u003cp\u003eGroup 4 (TK2\u0026thinsp;+\u0026thinsp;EP): BONDMER Lightless Ⅱ + ESTECEM Plus Universal\u003c/p\u003e \u003cp\u003eThe lot number, manufacturers, and detailed chemical composition of the aforementioned bonding agents and the zirconia cleaning paste are presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Application procedures for each product are detailed in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. All operations were conducted at room temperature (25\u0026thinsp;\u0026plusmn;\u0026thinsp;1℃). The curing modes and storage temperature of four universal adhesives selected in this study are demonstrated in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. \u003cb\u003eSurface appearance of each universal adhesive applied to zirconia.From left to right: 3M1, 3M2, TK1, TK2; The upper parts of TK1 and TK2 were coated twice.\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe lot number, manufacturers and chemical formulation of the materials used in present study.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCode\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMaterials\u003c/p\u003e \u003cp\u003e(Lot No.)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eManufacturer\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChemical Formulation\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3M1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSingle Bond Universal Adhesive\u003c/p\u003e \u003cp\u003e(4075B)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e3M Deutschland GmbH 41453 Neuss (Germany)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10-MDP, dimethacrylate resins, HEMA, polyalkenoic acid copolymer, filler, ethanol, water, CQ, γ-MPTS, silane\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3M2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eScotchbond Universal Plus Adhesive\u003c/p\u003e \u003cp\u003e(10860837)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10-MDP, 4,6-dibromoresorcinol-based dimethacrylate diester, DMAE-B, HEMA, acrylic-itaconic copolymer, filler, ethanol, water, CQ, γ-MPTES, APTES, silica\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRUC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRelyX\u0026trade; Ultimate Clicker Adhesive Resin Cement\u003c/p\u003e \u003cp\u003e(12129322)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eBase paste: methacrylate monomers, radiopaque, silanated fillers, initiator components, stabilizers, rheological additives\u003c/p\u003e \u003cp\u003eCatalyst paste: methacrylate monomers, radiopaque, alkaline (basic) fillers, initiator components, stabilizers, pigments, rheological additives, fluorescence dye, dual-cure activator for single bond universal adhesive\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTK1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ePALFIQUE UNIVERSAL BOND\u003c/p\u003e \u003cp\u003e(Bond A:133, Bond B:611)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003eTokuyama Dental Corp.\u003c/p\u003e \u003cp\u003e(Japan)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eBond A: 3D-SR monomer, MTU-6, HEMA, Bis-GMA, TEGDMA, acetone, BHT\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eBond B: γ-MPTES, borate, TMBHP, acetone, isopropyl alcohol, water, BHT\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTK2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eBONDMER Lightless Ⅱ\u003c/p\u003e \u003cp\u003e(Bond A:056, Bond B:540)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eBond A: phosphate acid, Bis-GMA, MTU-6, HEMA, TEGDMA, acetone\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eBond B: γ-MPTES,acetone, ethanol, water, borate catalyst, peroxide\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eESTECEM Plus Universal\u003c/p\u003e \u003cp\u003e(A087B8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eBis-GMA, TEGDMA, Bis-MPEPP, silica-zirconia filler, CQ, BPO\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIVO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIvoclean\u003c/p\u003e \u003cp\u003e(Z06KJ2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eIvoclar-Vivadent\u003c/p\u003e \u003cp\u003e(Liechtenstein)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eZirconium oxide, water, polyethylene glycol, sodium hydroxide, pigments, additives\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e10-MDP, 10-methacryloyloxydecyl dihydrogen phosphate; HEMA, 2-hydroxyethyl methacrylate; γ-MPTS, γ-methacryloxypropyl trimethoxy silane; DMAE-B: dimethylaminoethanol bitartrate; CQ: camphorquinone; γ-MPTES, γ-mercaptopropyl trimethoxysilane; APTES, 3-aminopropyl triethoxysilane; 3D-SR monomer, three dimensional self-reinforcing monomer; MTU-6, 6-methacryloxyhexyl 2-thiouracil-5-carboxylate; Bis-GMA, bisphenol-A-diglycidylmethacrylate; TEGDMA, triethylene glycol dimethacrylate; BHT, butylated hydroxytoluene ; TMBHP, tert-butyl hydroperoxide; BPO, benzoyl peroxide\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eApplication procedures of the bonding agents and cleaning paste used in present study.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCode\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eApplication procedures\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e3M1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1. Apply the adhesive to the zirconia surface and resin cylinders base\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2. Gently blow dry the adhesive for 15 s to a thin uniform coat\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3. Light cure for 20 s\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e3M2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1. Apply the adhesive to the zirconia surface and resin cylinders base\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2. Gently blow dry the adhesive for 15 s to a thin uniform coat\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3. Light cure for 20 s\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eTK1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1. Apply 1 drop of liquid A and liquid B into mixing plate. Gently mix A and B together\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2. Apply the TK1 mixture to the zirconia surface and resin cylinders base respectively\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3. Gently air-blow dry the adhesive for 15 s to a thin uniform coat\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eTK2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1. Apply 1 drop of liquid A and liquid B into mixing plate. Gently mix A and B together until the adhesive turns a uniform green\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2. Apply the TK2 mixture to the zirconia surface and resin cylinders base respectively\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3. Gently air-blow dry the adhesive for 15 s to a thin uniform coat\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eRUC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1. Apply appropriate amount of base paste to the resin cylinders base with syringe\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2. Immediately after applying adhesive, lightly place the resin cylinder onto zirconia surface\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.Remove excess cement and light cure for 20 s on each side of the resin cylinder at a distance of approximately 5 mm from the surface\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eEP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1. Apply appropriate amount paste to the resin cylinders base\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2. Gently blow dry the cement for 15 s to a thin uniform coat, lightly place the resin cylinder onto zirconia surface\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3. Remove excess cement within 1 to 3.5 minutes.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eIVO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1. Cover the entire bonding surface of zirconia with a layer of Ivoclean using a microbrush or bush.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2. Allow 20 seconds for the cleaning action of Ivoclean to take effect\u003c/p\u003e \u003cp\u003e3. Thoroughly rinse with water spray and dry with oil-free air.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCuring modes and storage temperature of the four types of universal adhesives\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUniversal adhesive\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCuring mode\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStorage temperature\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3M1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003elight-cure\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u0026ndash;25℃\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3M2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003elight-cure\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u0026ndash;25℃\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTK1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eself-cure\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u0026ndash;10℃, keep refrigerated and sit until it reaches room temperature before opening.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTK2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eself-cure\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u0026ndash;25℃\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSurface preparation\u003c/h3\u003e\n\u003cp\u003eThe bonding surfaces of zirconia cubes were treated by sandblasting with 125 \u0026micro;m aluminum oxide particles for 60 s at a distance of 10 mm, an angle of 90\u0026deg;, and a pressure of 2.8 bar. Following sandblasting, the bonding surfaces of all zirconia specimens were placed face-down and underwent ultrasonic cleaning in distilled water for 5 min and gentle air-blowing for 15 s subsequently. The application of IVO followed the manufacturer\u0026rsquo;s instruction: it was applied to the prepared zirconia surface for 60 s, followed by rinsing with distilled water for 15 s and gentle air-blowing.\u003c/p\u003e\n\u003ch3\u003eApplication procedure\u003c/h3\u003e\n\u003cp\u003eThe resin cylinders were bonded to the zirconia surfaces using a consistent clamp, ensuring that the same pressure (10 N) was applied across all groups. Excess resin cement surrounding the bonding interface was carefully removed using a small brush, taking care not to move or disturb the bonding interface. The procedures for light curing (Kerr Demi Plus, Orange, CA, United States) and the resin cement bonding were described in detail in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eA diagram of the bonding of the resin cylinders to the zirconia surface is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eShear bond strength (SBS) test\u003c/h3\u003e\n\u003cp\u003eThe resin cylinder specimens bonded with each bonding agent were further divided into three subgroups, with 18 resin cylinder specimens in each subgroup. The three subgroups were assigned to different storage conditions: storage in distilled water at 37℃ for 24 h, 5,000 cycles of thermal cycling, and 10,000 cycles of thermal cycling, respectively. One-third of the resin specimens were tested after storing in an incubator (Shanghai Lichen Bangxi Instrument Technology Co., Ltd., China) with distilled water at 37℃ for 24 h. The remaining specimens underwent thermal cycling in a thermocycler (THE 1400, SD Mechatronik, Germany): one-third underwent 5,000 cycles of thermal cycling between 5℃ and 55℃, with a dwell time of 25 s per bath and a transfer time of 10 s. One-third underwent 10,000 cycles of thermal cycling between 5℃ and 55℃, with a dwell time of 25 s per bath and a transfer time of 10 s.\u003c/p\u003e \u003cp\u003eThe SBS test was conducted using a universal testing machine (WD-200 Weidu, Wenzhou, China) with a crosshead speed of 1 mm/min (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e) .The SBS formula used was P(MPa)\u0026thinsp;=\u0026thinsp;F(N)/S(mm\u003csup\u003e2\u003c/sup\u003e).\u003c/p\u003e \u003cp\u003eOut of 18 results in each group, the highest 4 and lowest 4 data points were discarded, and the remaining 10 were considered for analysis (n\u0026thinsp;=\u0026thinsp;10).\u003c/p\u003e\n\u003ch3\u003eAdhesive remnant index (ARI) score\u003c/h3\u003e\n\u003cp\u003eThe ARI scoring was based on digital photographs with the help of a dental digital camera (EyeSpecial C-IV, Shofu, Kyoto, Japan). Following the SBS test, the bonding surfaces of the zirconia and resin specimens were observed. The ARI failure mode was represented by a scale with 5 levels (Score A to Score E) as follows:\u003c/p\u003e \u003cp\u003eScore A: Almost no cement or adhesive remained on the zirconia surface (0%);\u003c/p\u003e \u003cp\u003eScore B: 1% \u0026minus;\u0026thinsp;49% of the cement and adhesive remained on the zirconia surface;\u003c/p\u003e \u003cp\u003eScore C: 50% \u0026minus;\u0026thinsp;99% of the cement and adhesive remained on the zirconia surface;\u003c/p\u003e \u003cp\u003eScore D: Almost all the cement and adhesive remained on the zirconia surface (100%);\u003c/p\u003e \u003cp\u003eScore E: The adhesive layer fractured cohesively within the material, leaving remnants on both the zirconia and resin cylinder surfaces.\u003c/p\u003e \u003cp\u003eThe ARI scoring criteria designated in the present study are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. To minimize error, the images were scored independently by three calibrated examiners. In cases of disagreement for each specimen, a majority opinion was adopted.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eOut of 18 results in each group, the highest four and lowest four data points were discarded, and the remaining 10 were considered for analysis (n\u0026thinsp;=\u0026thinsp;10). The three-way ANOVA (brands, generations and storage conditions) was used to analyze the influence of these factors on the results. Additionally, multiple comparisons were performed for all groups using either the Tukey HSD test or the Games-Howell test, depending on the homogeneity of variance assumption. This analysis was conducted using SPSS version 27.0, with a significance level of α\u0026thinsp;=\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSurface evaluation\u003c/h3\u003e\n\u003cp\u003eResin cylinder surfaces after debonding were examined with a field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectrometry (EDS; Phenom Pharos G2, Netherlands) to determine elemental composition and distribution.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eShear bond strength (SBS)\u003c/h2\u003e \u003cp\u003eThe mean values and standard deviation for each group are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eThe SBS intergroup differences measured for the four groups 3M1, 3M2, TK1, and TK2 under a 24 h, 37℃ constant-temperature water storage were significant (p\u0026lt;0.05).3M2 and TK1 exhibited stronger adhesive strength, significantly higher than that of 3M2 and TK1.\u003c/p\u003e \u003cp\u003eAfter 24 h water storage, the bond strengths of the four adhesives were respectively as follows: 3M2, TK1, TK2, and 3M1. Compared to 3M1, 3M2 exhibited significantly higher immediate bond strength (p\u0026lt;0.05), while TK1 and TK2 demonstrated similar immediate bond strengths (p\u0026gt;0.05).\u003c/p\u003e \u003cp\u003eAfter 5,000 and 10,000 thermal cycles, the bond strength of all groups showed significant degradation. Solely TK1 can be detected, while the others registered null values. Especially after 5,000 thermal cycles, TK1 still performed well. After 10,000 thermal cycles, although no statistically significant differences were observed in SBS of the four adhesives, which meant the differences were negligible, TK1 still yielded detectable SBS data in the testing machine (p\u0026gt;0.05).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSBS values (MPa) for four bonding agents in three different storage conditions (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStorage condition\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3M1\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3M2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTK1\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eTK2\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24 h\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.86\u0026thinsp;\u0026plusmn;\u0026thinsp;0.49\u003csup\u003e1,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.99\u0026thinsp;\u0026plusmn;\u0026thinsp;1.94\u003csup\u003e1,b\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.89\u003csup\u003e1,b\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.98\u0026thinsp;\u0026plusmn;\u0026thinsp;1.16\u003csup\u003e1,a,b\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5,000 cycles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003csup\u003e2,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003csup\u003e2,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.96\u0026thinsp;\u0026plusmn;\u0026thinsp;1.052\u003csup\u003e2,b\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003csup\u003e2,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10,000 cycles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003csup\u003e2,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003csup\u003e2,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.27\u003csup\u003e3,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003csup\u003e2,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe same numbers indicate no significant differences in SBS within the same bonding agent under different storage conditions (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eThe same lowercase letters indicate no significant differences in SBS among different bonding agents under the same storage condition (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThree-way ANOVA results (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e) revealed that storage conditions (p\u0026lt;0.001, F\u0026thinsp;=\u0026thinsp;627.488), brands (p\u0026lt;0.05, F\u0026thinsp;=\u0026thinsp;7.528), and generations (p\u0026lt;0.05, F\u0026thinsp;=\u0026thinsp;6.106) all significantly influenced SBS. Statistically significant interactions were found between three factors: Storage conditions * Brands (p\u0026lt;0.001, F\u0026thinsp;=\u0026thinsp;15.410), Storage conditions * Generations (p\u0026lt;0.001, F\u0026thinsp;=\u0026thinsp;16.970), and Brands * Generations (p\u0026lt;0.001, F\u0026thinsp;=\u0026thinsp;55.095). Furthermore, notably, the interaction among the three factors\u0026mdash;Storage conditions, Brands, and Generations\u0026mdash;also demonstrated statistical significance (p\u0026lt;0.001, F\u0026thinsp;=\u0026thinsp;11.807).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThree-way ANOVA results of all bonding agents in different storage conditions.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSource\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003edf\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean square\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCorrected model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e78.811\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e128.371\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntercept\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e565.806\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e921.607\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStorage conditions\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e385.236\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e627.488\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBrands\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4.622\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7.528\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.007\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGenerations\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3.749\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6.106\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.015\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStorage conditions * Brands\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9.461\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e15.410\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStorage conditions * Generations\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10.418\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16.970\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBrands * Generations\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e33.825\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e55.095\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStorage conditions * Brands* Generations\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7.429\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e11.807\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e, \u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e, \u003cspan refid=\"Tab8\" class=\"InternalRef\"\u003e8\u003c/span\u003e demonstrated the results of Games-Howell test and Tukey HSD test.\u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e indicated that both the 3M and TK adhesives demonstrate significantly superior performance under 24 h water storage compared to 5,000 and 10,000 thermal cycles later. Under 24 h water storage, 3M was slightly higher than TK, but the difference was not statistically significant. After 5,000 thermal cycles, the 3M group totally debonded, while the TK group retained certain adhesive strength, with statistically significant difference existing between two groups (p\u0026lt;0.05). After 10,000 thermal cycles, both 3M and TK exhibited negligible adhesive strength with no statistical difference (p\u0026gt;0.05), though measurable values remained detectable in the TK group.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe mean SBS values (MPa) the two bonding agent brands (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStorage condition\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3M\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTK\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24 h\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.93\u0026thinsp;\u0026plusmn;\u0026thinsp;1.76\u003csup\u003e1,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.54\u0026thinsp;\u0026plusmn;\u0026thinsp;1.16\u003csup\u003e1,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5,000 cycles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.00\u003csup\u003e2,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.48\u0026thinsp;\u0026plusmn;\u0026thinsp;1.68\u003csup\u003e2,b\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10,000 cycles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.00\u003csup\u003e2,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.20\u003csup\u003e3,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe same numbers indicate no significant differences in SBS within the same bonding agent under different storage conditions (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eThe same lowercase letters indicate no significant differences in SBS among different bonding agents under the same storage condition (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eSBS of both generation-1 and generation-2 adhesives decreased significantly after 5,000 thermal cycles compared to the SBS under 24 h of 37℃ water storage (Table\u0026nbsp;\u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e). The SBS of generation-1 adhesives was consistently detectable, even remained significantly higher than that of the generation-2 adhesives (p\u0026lt;0.05) post 5,000 thermal cycles, primarily attributed to TK1. After 10,000 thermal cycles, both groups become virtually ineffective.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab7\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe mean SBS values (MPa) of the two bonding agent generations (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStorage condition\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGeneration1\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGeneration2\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24 h\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.48\u0026thinsp;\u0026plusmn;\u0026thinsp;0.95\u003csup\u003e1,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.98\u0026thinsp;\u0026plusmn;\u0026thinsp;1.87\u003csup\u003e1,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5,000 cycles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.48\u0026thinsp;\u0026plusmn;\u0026thinsp;1.68\u003csup\u003e2,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.00\u003csup\u003e2,b\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10,000 cycles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.20\u003csup\u003e3,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.00\u003csup\u003e2,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe same numbers indicate no significant differences in SBS within the same group under different storage conditions (p\u0026gt;0.05).\u003c/p\u003e \u003cp\u003eThe same lowercase letters indicate no significant differences in SBS among different brands under the same storage condition (p\u0026gt;0.05).\u003c/p\u003e \u003cp\u003eIntegrating the three storage conditions, the SBS ranked respectively as TK1, 3M2, TK2, and 3M1. However, no statistical differences (Table\u0026nbsp;\u003cspan refid=\"Tab8\" class=\"InternalRef\"\u003e8\u003c/span\u003e, p\u0026gt;0.05) were observed among the four adhesives. SBS value of TK1 demonstrated 3.08\u0026thinsp;\u0026plusmn;\u0026thinsp;2.59 MPa, slightly higher than the three other bonding agents, attributed to TK1's superior performance compared to the other groups post thermal cycling.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab8\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 8\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe mean SBS values (MPa) of the four bonding agent types (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGeneration\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3M\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTK\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003egeneration1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.62\u0026thinsp;\u0026plusmn;\u0026thinsp;2.35\u003csup\u003e1,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.08\u0026thinsp;\u0026plusmn;\u0026thinsp;2.59\u003csup\u003e1,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003egeneration2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.33\u0026thinsp;\u0026plusmn;\u0026thinsp;3.52\u003csup\u003e1,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.66\u0026thinsp;\u0026plusmn;\u0026thinsp;2.47\u003csup\u003e1,a\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe same numbers indicate no significant differences in SBS within the same group under different storage conditions (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eThe same lowercase letters indicate no significant differences in SBS among different brands under the same storage condition (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eFailure modes\u003c/h2\u003e \u003cp\u003eThe ARI scores for the four adhesives are shown in Table\u0026nbsp;\u003cspan refid=\"Tab9\" class=\"InternalRef\"\u003e9\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e. The two 3M products both exhibited a strong trend to Mode A under all three storage conditions. 3M1 remained at A under all conditions, while 3M2 completely degraded from B to A after thermal cycling. In contrast, TK products performed three distinct modes\u0026mdash;C, D, and E\u0026mdash;under 24 h conditions. TK1 concentrated in E within 24 h, and as the number of thermal cycling increased, it decreased from C and D to concentration in A and B. TK2 showed a similar trend: the initial dispersion of results across score B, C, D, and E gradually diminished, ultimately concentrating in categories A and B post thermal cycling.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab9\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 9\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eARI scores of each group with different bonding agents bonded to zirconia.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eGroup tested\u003c/p\u003e \u003cp\u003e(24 h/5,000 cycles/10,000 cycles)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"6\" nameend=\"c7\" namest=\"c2\"\u003e \u003cp\u003eARI scores\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3M1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10/10/10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e0/0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0/0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0/0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0/0/0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3M2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6/10/10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e4/0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0/0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0/0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0/0/0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTK1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0/0/4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e0/0/6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1/4/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0/5/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e9/1/0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTK2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0/4/8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e1/6/2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2/0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4/0/0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3/0/0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eSurface characterization\u003c/h2\u003e \u003cp\u003eIn this study, the specimens after 5,000 thermal cycles in each group were selected for SEM image acquisition and elemental analysis. Air bubbles in the adhesives could be observed on the surfaces of debonded resin cylinders in groups 3M1, 3M2 and TK2 (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e). The elemental composition and distribution of carbon(C), oxygen(O) and silicon(Si) on the surface of four groups of resin cylinders were shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eComparison of bonding agents\u003c/h2\u003e \u003cp\u003eThis study was aimed at evaluating the impacts of adhesives under different storage conditions, from various brands and of two generations on the bonding performance between zirconia ceramics and resin. According to Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e, the bond strength of TK adhesive after 5,000 thermal cycles was statistically significantly higher than that of failed 3M specimens (p\u0026lt;0.05) whereas no significant differences in bond strength were observed under other storage conditions. Therefore, the null hypothesis that 3M and TK adhesives exhibit equivalent bonding performance under the same storage condition and generation could be partially rejected by these outcomes.\u003c/p\u003e \u003cp\u003eAs detailed in Table\u0026nbsp;\u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e, the first-generation adhesives displayed significantly higher in SBS compared to failed second-generation specimens after 5,000 thermal cycles (p\u0026lt;0.05), indicating the intergenerational influence on bonding efficiency. This intergenerational influence manifested exclusively in part of the outcomes, partially rejecting the null hypothesis that generation-1 and generation-2 adhesives from the same brand show no difference in SBS under identical storage conditions.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eInfluence of solvent components\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e demonstrated SBS of four adhesives from various brands and generations under different storage conditions. Unexpectedly, only TK1 exhibited significantly higher SBS than other debonded counterparts(p\u0026lt;0.05).After 10,000 thermal cycles, TK1 remained detectable values, though decaying to levels showing no statistical difference from other groups. Therefore, from a statistical perspective combining both bonding strength and durability, TK1 showes superior adhesive property among the four groups.\u003c/p\u003e \u003cp\u003eWater and organic solvent are both indispensable/imperative components of adhesives. Organic solvent acts as carriers of the monomers into the collagen interfibrillar spaces[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. And water is added to trigger the ionization of the respective phosphate monomer[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].While within the bonding interface, enhanced bonding strength is associated with lower concentration and hydrophilicity of solvent[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Hydrolysis is considered as the main reason for bonding failure. Residual solvent was found to inhibit the polymerization of resin and induce deterioration of hybrid layer, thus damage the clinical performance of adhesives[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Since composition and concentration of solvent are critical determinants for adhesive bonding strength[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e], air-blowing is generally executed in clinical practice to accelerate volatilization and thus decrease extent of solvent within the bonding interface.\u003c/p\u003e \u003cp\u003eEthanol and isopropanol are both hydrophilic monomers. When employed as solvents, they could aid in the wetting of dentin matrix, the diffusion of resin monomers in collagen network, the replacement of water from the dentin surface and provide dry bonding environment[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Content of hydrophilic monomers demonstrated a positive correlation with water absorption of resin polymer network. If hydrophilic monomers were not removed adequately by air-blowing, water absorption of the network would increase, resulting in degradation of the adhesive layer. Furthermore, after penetrating the polymer resin chains, the hydrophilic molecules acted as plasticizers to cause expansion of the network and reduced the friction between polymer chains, softening the material[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn this experiment, TK1 exhibited relatively better SBS than TK2 (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Compared to the refrigeration-requiring TK1, TK2 is allowed to be stored at room temperature (2\u0026ndash;25℃) and with the replacement of solvent composition from isopropanol to ethanol with increase in concentration (from 10%-30% to 25%-35%). Ethanol has a lower boiling point than isopropanol and is therefore more volatile at room temperature[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Sceptically, the adjustment of solvent concentration and type might expedite the evaporation of solvent under identical air-blowing step, contributing to the difference in thickness and trait of the adhesive layer between TK1 and TK2 (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Researches have reported that surface heterogeneity[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e] and excessive thickness[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e] of the bonding layer will result in decrease in adhesion force. Furthermore, if room temperature preservation led to partial evaporation of ethanol requires further validation.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003ePerformance of silane\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e demonstrated that 3M2 exhibited significantly higher immediate SBS than 3M1 (p\u0026lt;0.05). 3M officially claims that when used alone, 3M2 exhibited advanced bonding to glass-ceramics, reaching the gold standard level of traditional, separate silanes. This breakthrough is attributed to the modified silane coupling agents in 3M2 components. The siliane coupling agent contained in 3M1 is γ-MPTS, and the inorganic phase is vitreous silica. 3M2 included the modified organic silane components[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. γ-MPTES and APTES were used as siliane coupling agents and the inorganic phase was synthetic amorphous silica. It is suspected that γ-MPTES and APTES of 3M2 co-hydrolyzed in solvent and condensed with silica to form siloxane bond (Si-O-Si), generating a thick hybrid silane layer[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Meanwhile, basic amino groups are generated, neutralizing excess acidic monomers and bonding with resin to enhance the connection between siliane and resin, which is consistent with prior findings[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. Furthermore, γ-MPTES reduced the surface tension of the adhesive, which increased the wettability of the adhesive to zirconia surface and thus improved the bonding performance[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. In addition, APTES could also react with organic compounds such as epoxy resin to silanize them, increasing bonding strength between the adhesive and inorganic ingredients[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eThe difference between single-bottle and two-bottle universal adhesives\u003c/h2\u003e \u003cp\u003eSingle-bottle adhesives are generally light-cure system, and two-bottle bonding agents mainly belong to self-cure system. To meet a variety of requirements, single-bottle adhesives pack all chemical ingredients in a single bottle of agent. Long-term storage in acidic condition for silane coupling agents lead to emergence of hydrolysis, dehydration and condensation, forming oligomers that cannot bond to glass ceramics. Meantime, acidic functional monomers also undergo hydrolysis reactions, further affecting bonding performance[\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. Extra addition of silane coupling agent is necessary for potent bonding to ceramic materials. Material deterioration is avoided fundamentally in two-bottle system by physically isolating incompatible chemical components into two containers[\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e], such as segregating silane coupling agents and acidic functional monomers to enhance effective adhesion to ceramics[\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAdhesives from TK brand demonstrated higher SBS than products from 3M post thermal cycling (Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). Among the four adhesives adopted in this study, 3M1 and 3M2 were classified as single-bottle, light-curable adhesives, while TK1 and TK2 belonged to two-bottle, self-cure system. The borate and peroxide included in TK1 and TK2 constituted potent chemical polymerization initiator. The borate catalyst reacted with acidic three-dimensional self-reinforcing (3D-SR) monomers to form boron compounds. The compounds then were oxidized by acidic monomers and generated highly active initiators for chemical polymerization[\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]. It has been reported that adhesives including borate initiators displayed higher monomer conversion rate than camphorquinone based light-cure adhesives[\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e], in line with the present study. Speculation has been drawn that the outstanding performance of TK post thermal cycling was attributed to the stability of the initiator and the high monomer conversion rate it generated.\u003c/p\u003e \u003cp\u003eAdditionally, 3M2 displayed slightly higher SBS than TK1 after 24 h water bath (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Nevertheless, a distinct difference in failure mode of these two groups were observed in Table\u0026nbsp;\u003cspan refid=\"Tab8\" class=\"InternalRef\"\u003e8\u003c/span\u003e: For 3M2, most adhesive and cement remained in resin surfaces while the cohesive fracture occurred in TK1 on account of exceptional adhesion to both zirconia and resin surface. It is speculated that the diversified composition of these two adhesives determined divergent material property and consequently accounted for the discrepancy in failure mode.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003eEffect of storage conditions\u003c/h2\u003e \u003cp\u003eThermal stress and hydrolysis induced by thermal cycling between 5\u0026deg;C and 55\u0026deg;C stimulated the effect of intraoral temperature changes. 10,000 cycles represented approximately one year of oral functional status in clinical practice, while 5,000 cycles stood for six months[\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSBS declined significantly post thermal cycling (p\u0026lt;0.05). After 5,000 cycles, all four groups showed significant attenuation, and almost completely debonded after 10,000 cycles (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).These results were consistent with previous study[\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. Therefore, rejecting the null hypothesis: (3) There is no difference in SBS under different storage conditions for adhesives the same brand and generation.\u003c/p\u003e \u003cp\u003eIt is speculated that the rapid decline in SBS post thermal cycling was related to the HEMA component contained in all four adhesives (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). HEMA is a highly hydrophilic functional monomer, which can reduce the viscosity of resin to form a more uniform bonding layer, promote resin infiltration and penetration into the base tooth dentin and improve the water absorption of deeper dentin[\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHowever, akin to what previous researches have demonstrated, HEMA could decrease the conversion degree of monomers[\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e] and impact long-term bonding performance due to the water absorption and adhesive interface hydrolysis caused by its hydrophilia[\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003eExplanation of failure modes\u003c/h2\u003e \u003cp\u003eAll four universal adhesives selected for this study contained components containing Si elements. After 5,000 thermocycles, air bubbles were observed on the surface of debonding resin cylinders in groups 3M1, 3M2 and TK2 due to solvent evaporation in the adhesive, while there were no bubbles on the surface of resin cylinders in group TK1 and the control group (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e). Moreover, on the specimen surfaces, only TK1 and the control group failed to be detected containing the Si element, while Si in the residual adhesives on the surface were detected in the other 3 groups. It is indicated that for most specimens in the TK1 group after 5,000 thermal cycles, the adhesive layer remained on the surface of zirconia cubes, which is consistent with the fracture mode results observed in Table\u0026nbsp;\u003cspan refid=\"Tab9\" class=\"InternalRef\"\u003e9\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eAdhesives of two brands exhibited completely different failure modes. Two types of adhesives of 3M showed the trend to remain on the resin surface while almost no residue on the zirconia surface, particularly post thermal cycling. On the other hand, adhesives from TK tended to remain on the zirconia surface. And surprisingly, there was a phenomenon where the adhesive was scattered both on the resin and zirconia surface (Table\u0026nbsp;\u003cspan refid=\"Tab9\" class=\"InternalRef\"\u003e9\u003c/span\u003e), namely cohesive failure of adhesives, which belonged to the fracture occurring inside the adhesive layer[\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e, \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eYuta Tsuji analyzed the failure mode of epoxy-hydroxylated layer, supposing the interfacial failure and cohesive failure were competing with each other. When the maximum force required for interfacial failure exceeded the maximum force for cohesive failure, cohesive failure occurred. Otherwise, the interfacial failure occurred[\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. Similarly, it is speculated that when the chemical interaction on the interface is sufficient, fractures are forced to occurred inside the bonding layer, resulting in the cohesive failure of TK adhesives.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003eConsideration of chair-side convenience and clinical bonding performance\u003c/h2\u003e \u003cp\u003eThe four universal adhesives selected in this study have certain differences in curing modes and storage temperature variations, representing varying degrees of clinical convenience, as shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. TK1 is a self-cure adhesive without light-cure step, simplifying the chair-side procedures. But its obligatory requirement of refrigerated storage increases the complexity of material storage to a certain extent. TK2 changes the storage conditions to room temperature with non-essential light-cure step, which is more clinically convenient among the four groups. In contrast, the two universal adhesives from 3M company both require the light-cure step, owning the same operational procedures of All-in-1 system.\u003c/p\u003e \u003cp\u003eThe evaluation of dental adhesive material is increasingly oriented toward streamlining operational procedures, mitigating technological sensitivity and reducing chair-side time. Nevertheless, simplification and novelty should not be achieved at the expense of/compromise material properties[\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e]. In the context of porcelain veneer cementation, clinicians maintain elevated psychological expectations regarding bonding efficacy achieved through complicated adhesive protocols. Whereas occasionally adequate retention forms afford robust guarantee for prosthetic retention. As auxiliary force for retention, adhesion is permitted a certain degree of compromise in its strength. Consequently, luting products with simplified procedures exemplified self-adhesive resin cement have come out in response to clinical needs.\u003c/p\u003e \u003cp\u003eThe Tokuyama corporation incorporated a novel initiator system to omit the light-cure process of the conventional \u0026ldquo;applying\u0026mdash;air-blowing\u0026mdash;light-curing\u0026rdquo; protocol. One of the distinctions between the two generations lies in the broadened storage temperature range of TK2, with no more requirement for refrigeration.\u003c/p\u003e \u003cp\u003eRefrigerated storage is necessary to preserve efficacy of resin-based products[\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e], especially in summer or in regions of elevated ambient temperature. As demonstrated in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, it is evident that TK1 revealed higher SBS among all groups under different storage conditions. While TK2, without refrigeration, exhibited slightly weaker SBS post thermal cycling, seemingly indicating in this experiment the simplification of operation made concessions in terms of bonding strength. However, 3M adhesives with more complex chair-side operation contrarily showed weaker SBS than TK1 post thermal cycling (Table\u0026nbsp;\u003cspan refid=\"Tab8\" class=\"InternalRef\"\u003e8\u003c/span\u003e), manifesting that application complexity could not define the adhesive property of materials, which were not contradictory. Though, TK1 is a two-bottle adhesive, thorough mixing is needed before application to the surface. In the future, the development target for ideal clinical products should be of simple operational steps and wide temperature adaption range, meanwhile still providing sufficiently strong bond strength, thereby achieving real simple but not simplistic clinical application.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003eDiscussion limitations\u003c/h2\u003e \u003cp\u003eThis in vitro study simulated oral functional condition via thermal cycling, lacking actual temperature of oral cavity and salivary immersion of specimens. Surface treatment solely encompassed sandblasting and cleaning of zirconia and resin cylinder bonding surface, without exploration of zirconia surface modification. Smooth and flat zirconia ceramic surfaces were employed as bonding interfaces in this study. Subsequent researches should include evaluation of various surface treatment methods of zirconia and explore in depth the best-matched pretreatment for each bonding agents, hereby to render instruction for clinical decisions.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003e1. The bond strength of universal adhesives of different generations and brands is material-dependent.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003e2. After 5,000 thermal cycles, the SBS differed significantly among brands and generations of adhesives, with TK1 exhibiting better performance in this study.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003e3. Technological advances have introduced user-friendly products with simplified application procedures. However, clinicians should adopt an evidence-based perspective and focus on clinical effect and experimental data of materials.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e3M1\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eSingle Bond Universal Adhesive\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e3M2\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eScotchbond\u0026trade; Universal Plus Adhesive\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eTK1\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ePALFIQUE UNIVERSAL BOND\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eTK2\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eBONDMER Lightless Ⅱ\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e3M\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eMinnesota Mining and Manufacturing\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eTK\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eTokuyama\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eThree-way ANOVA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eThree-way Repeated Measures Anova\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eHSD\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eHonestly Significant Difference\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSBS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eShear Bond Strength\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eBPO\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eBenzoyl peroxide\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCAD/CAM\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eComputer-Aided Design/Computer-Aided\u0026nbsp;Manufacturing\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eRUC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eRelyX\u0026trade; Ultimate Clicker Adhesive Resin Cement\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eEP\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eESTECEM Plus Universal\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eIVO\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eIvoclean\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e10-MDP\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003e10-methacryloyloxydecyl dihydrogen phosphate\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eHEMA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003e2-hydroxyethyl methacrylate\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eγ-MPTS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eγ-methacryloxypropyl trimethoxy silane\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eDMAE-B\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003edimethylaminoethanol bitartrate\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCQ\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ecamphorquinone\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eγ-MPTES\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eγ-mercaptopropyl trimethoxysilane\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eAPTES\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003e3-aminopropyl triethoxysilane\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e3D-SR monomer\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ethree dimensional self-reinforcing monomer\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eMTU-6\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003e6-methacryloxyhexyl 2-thiouracil-5-carboxylate\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eBis-GMA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ebisphenol-A-diglycidylmethacrylate\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eTEGDMA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003etriethylene glycol dimethacrylate\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eBHT\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ebutylated hydroxytoluene\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eTMBHP\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003etert-butyl hydroperoxide\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eTHE\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eThermocycler\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eMPa\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eMegapascal\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eN\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eNewton\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003emm\u003csup\u003e2\u003c/sup\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003esquare millimeter\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eARI\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eAdhesive remnant index\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eFE-SEM\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003efield emission scanning electron microscopy\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eEDS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eEnergy Dispersive Spectroscopy\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSD\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eStandard Deviation\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSEM\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003escanning electron microscope\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003ch2\u003eDeclarations\u003c/h2\u003e \u003cp\u003e \u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e \u003cp\u003eAll procedures in this study complied with the relevant guidelines and regulations, including the Helsinki Declaration.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent for publication\u003c/strong\u003e \u003cp\u003eNot applicable.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eClinical trial number\u003c/h2\u003e \u003cp\u003eNot applicable. This study is a laboratory-based investigation and does not involve a clinical trial. Therefore, no clinical trial number has been assigned.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eCompeting interests\u003c/h2\u003e \u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003e \u003cb\u003eFootnotes\u003c/b\u003e \u003c/h2\u003e \u003cp\u003e \u003cstrong\u003ePublisher\u0026rsquo;s Note\u003c/strong\u003e \u003cp\u003eSpringer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eLiaoning Provincial Joint Science and Technology Program (Natural Science Foundation - General Program), Project Number: 2025-MSLH-743\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eProtocol design: JF, JC, YK; Experiments performance: JC; Data acquisition: JC, YX; Data analysis: JC; Drafted the manuscript: JC, YX, YW, XL, HS; Figure preparation: YX, YW; Revision of manuscript: JF, YK, HS; All the authors have read and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eNot applicable.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eAll data generated or analyzed during this study are included in this published article and its supplementary information files.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003ePapadogiannis D, Dimitriadi M, Zafiropoulou M, Gaintantzopoulou MD, Eliades G. Universal Adhesives: Setting Characteristics and Reactivity with Dentin. Mater (Basel). 2019;12(10):1720.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eli R, Wang C, Ma SQ, Liu ZH, Zang CC, Zhang WY, et al. High bonding strength between zirconia and composite resin based on combined surface treatment for dental restorations. J Appl Biomater Funct Mater. 2020;18:2280800020928655.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThompson JY, Stoner BR, Piascik JR, Smith R. Adhesion/cementation to zirconia and other non-silicate ceramics: where are we now? Dent Mater. 2011;27(1):71\u0026ndash;82.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGoracci C, Di Bello G, Franchi L, Louca C, Juloski J, Juloski J, et al. Bracket Bonding to All-Ceramic Materials with Universal Adhesives. Mater (Basel). 2022;15(3):1245.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLopes RO, Somacal DC, Modena CFM, Spohr AM. Are Universal Adhesives Effective for Bonding to Zirconia in the Long Term? Contemp Clin Dent. 2023;14(4):307\u0026ndash;12.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eArandi NZ. The Classification and Selection of Adhesive Agents; an Overview for the General Dentist. Clin Cosmet Investig Dent. 2023;15:165\u0026ndash;80.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHasanain FA, Nassar HM. Utilizing Light Cure Units: A Concise Narrative Review. Polym (Basel). 2021;13(10):1596.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKowalska A, Sokolowski J, Bociong K. The Photoinitiators Used in Resin Based Dental Composite-A Review and Future Perspectives. Polym (Basel). 2021;13(3):470.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHirokane E, Takamizawa T, Kasahara Y, Ishii R, Tsujimoto A, Barkmeier WW, et al. Effect of double-layer application on the early enamel bond strength of universal adhesives. 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Influence of different surface treatments on zirconia/resin shear bond strength using one-bottle universal adhesive. Adv Appl Ceram. 2018;118:70\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVasconcelos Monteiro R, Dos Santos DM, Chrispim B, Bernardon JK, Soares Porto T, De Souza GM. Effect of Universal Adhesives on Long-term Bond Strength to Zirconia. J Adhes Dent. 2022;24:385\u0026ndash;94.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLuque-Martinez IV, Perdig\u0026atilde;o J, Mu\u0026ntilde;oz MA, Sezinando A, Reis A, Loguercio AD. Effects of solvent evaporation time on immediate adhesive properties of universal adhesives to dentin. Dent Mater. 2014;30(10):1126\u0026ndash;35.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHiraishi N, Nishiyama N, Ikemura K, Yau JY, King NM, Tagami J, et al. Water concentration in self-etching primers affects their aggressiveness and bonding efficacy to dentin. 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J Chem Technol Biotechnol. 2019;94(2):343\u0026ndash;65.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFu J, Pan F, Kakuda S, Sharanbir KS, Ikeda T, Nakaoki Y, et al. The effect of air-blowing duration on all-in-one systems. Dent Mater J. 2012;31(6):1075\u0026ndash;81.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTang C, Mercelis B, Yoshihara K, Peumans M, Van Meerbeek B. Does the universal adhesive's film thickness affect dentin-bonding effectiveness? Clin Oral Investig. 2024;28(2):150.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTannen DL, Wallum AJ, Mitchell TM, Renda JJ, Vandewalle KS. Bond Strength of Silane-Containing Universal Bonding Agents to Lithium Disilicate. J Clin Exp Dent. 2025;17(4):e358\u0026ndash;65.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNishiyama N, Katsuki H, Horie K, Asakura T. Adsorbed behavior of spin-labeled silane coupling agent on colloidal silica studied by electron spin resonance. 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Dent Mater. 2016;32(10):1218\u0026ndash;25.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKibe K, Hatayama T, Shimada Y. In vitro performance of an autocured universal adhesive system in bonding to dentin. BMC Oral Health. 2023;23(1):933.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVidal CMP, Teixeira EC, Armstrong SR, Qian F. Comparison of Adhesion Performance of a Self-curing and a Light-curing Universal Adhesive to Various Dental Substrates and CAD/CAM Materials. J Adhes Dent. 2024;26:31\u0026ndash;40.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGale MS, Darvell BW. Thermal cycling procedures for laboratory testing of dental restorations. J Dent. 1999;27(2):89\u0026ndash;99.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMoradi Z, Akbari F, Valizadeh S. Effects of Universal Adhesive on Shear Bond Strength of Resin Cement to Zirconia Ceramic with Different Surface Treatments. Int J Dent. 2021;2021:5517382.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTang C, Ahmed MH, Yoshihara K, Peumans M, Van Meerbeek B. Multi-Parameter Characterization of HEMA/BPA-free 1- and 2-step Universal Adhesives Bonded to Dentin. J Adhes Dent. 2024;26:41\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbdelkhalek E, Hamama HH, Mahmoud SH. HEMA-free versus HEMA-containing adhesive systems: a systematic review. Syst Rev. 2025;14(1):17.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu D, Yao Y, Cifuentes-Jimenez CC, Sano H, \u0026Aacute;lvarez-Lloret P, Yamauti M, et al. Long-Term Dentin Bonding Performance of Universal Adhesives: The Effect of HEMA Content and Bioactive Resin Composite. J Funct Biomater. 2024;15(12):379.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKitahara S, Shimizu S, Takagaki T, Inokoshi M, Abdou A, Burrow MF, et al. Dentin Bonding Durability of Four Different Recently Introduced Self-Etch Adhesives. Mater (Basel). 2024;17(17):4296.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHu Y, Gao J, Huang X, Li Y, Chen Z, Zhan D, et al. The possibility of clinical bonding between metal/ceramic brackets to zirconia: in vitro study. Front Bioeng Biotechnol. 2024;12:1354241.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRamos RQ, Mercelis B, Ahmed MH, Peumans M, Lopes GC, Van Meerbeek B. Bonding of Composite Cements Containing 10-MDP to Zirconia Ceramics Without Dedicated Ceramic Primer. J Adhes Dent. 2024;26:135\u0026ndash;45.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJanson M, Bassier V, Liebermann A, Schoppmeier CM, Gregorio-Schinin\u0026agrave; MD. Composite Repair on Zirconia: Influence of Different Sandblasting Pretreatments and Various Universal Adhesives on Shear Bond Strength. J Adhes Dent. 2025;27:53\u0026ndash;64.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTsuji Y. Molecular Understanding of the Distinction between Adhesive Failure and Cohesive Failure in Adhesive Bonds with Epoxy Resin Adhesives. Langmuir. 2024;40(14):7479\u0026ndash;91.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCadenaro M, Josic U, Maravić T, Mazzitelli C, Marchesi G, Mancuso E, et al. Progress in Dental Adhesive Materials. J Dent Res. 2023;102(3):254\u0026ndash;62.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSabbagh J, Nabbout F, Jabbour E, Leloup G. The Effect of Expiration Date on Mechanical Properties of Resin Composites. J Int Soc Prev Community Dent. 2018;8(2):99\u0026ndash;103.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"shear bond strength (SBS), universal adhesive, zirconia, resin cement, light-less","lastPublishedDoi":"10.21203/rs.3.rs-8163770/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8163770/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eUniversal adhesives are widely used in the field of dental prosthetics owing to their broad applicability and clinical convenience. This study aims to evaluate the bonding performance of four adhesives on zirconia and resin material surfaces.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThe shear bond strength (SBS) test results of four adhesives including Single Bond Universal Adhesive (3M1), Scotchbond\u0026trade; Universal Plus Adhesive (3M2), PALFIQUE UNIVERSAL BOND (TK1) and BONDMER Lightless Ⅱ (TK2) were studied under three storage conditions: constant-temperature water storage at 37℃ for 24 h, 5,000 thermal cycles, and 10,000 thermal cycles. Three-way ANOVA, Tukey HSD test, and Games-Howell test were performed on the outcome data (α\u0026thinsp;=\u0026thinsp;0.05). The Adhesive Remnant Index is used to evaluate the debonding condition between resin and zirconia surfaces.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eAll four groups exhibited acceptable bond strength measured at 24 h in a 37℃ constant-temperature water bath and statistically significant differences were observed among the four groups (p\u0026lt;0.05). However, after thermal cycling, the bond strength of all groups showed significant decline, with only TK1 yielding detectable data. Three-way ANOVA results indicated that all factors\u0026mdash;storage conditions (p\u0026lt;0.001), brands (p\u0026lt;0.05), and generations (p\u0026lt;0.05)\u0026mdash;exerted significant effects on SBS. At the same time, the interaction among the three factors also showed significant statistical difference (p\u0026lt;0.001).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eThe bonding performance of universal adhesives of different generations and brands is material-dependent. After 5,000 thermal cycles, the SBS differed significantly among brands and generations of adhesives, with TK1 exhibiting better performance in this study. Technological advances have introduced user-friendly products with simplified application procedures. However, clinicians should adopt an evidence-based perspective and focus on clinical effect and experimental data of materials.\u003c/p\u003e","manuscriptTitle":"Does simplification signify compromise? Evaluation of different universal adhesives on shear bond strength","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-19 17:17:13","doi":"10.21203/rs.3.rs-8163770/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2e276b8a-75d6-4e68-90e8-03064ed77893","owner":[],"postedDate":"December 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-01-21T05:47:45+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-19 17:17:13","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8163770","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8163770","identity":"rs-8163770","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}