Does Composite Repair Time Affect Repair Protocol, Immediate or Delayed?

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Murat Can Ersen, Nevin Cobanoglu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7482603/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 15 Dec, 2025 Read the published version in BMC Oral Health → Version 1 posted 12 You are reading this latest preprint version Abstract Background: Composite resin restorations frequently require repair due to fractures, marginal defects, or esthetic failures. The effectiveness of composite repair depends heavily on the surface treatment applied prior to bonding. This study aimed to evaluate the effects of various surface treatment protocols on the shear bond strength(SBS) between composite resin layers in same-visit immediate repair and delayed repair conditions, using bulk-fill and nanohybrid composite resins. Methods: Two types of composite resin materials—NeoSpectra ST HV (nanohybrid) and Tetric N-Ceram Bulk-Fill—were tested. A total of ten surface treatment protocols were evaluated under both immediate and delayed repair conditions (n = 10 per subgroup). Following grinding with a diamond bur, the surfaces were treated with one of the following: phosphoric acid, universal adhesives (Single Bond Universal, Prime&Bond Universal), three application modes of Clearfil SE Bond (two-step, bond only without primer, or phosphoric acid application followed by bond only), Optibond FL without primer, or GC Modeling Liquid. Additionally, direct layering without any surface treatment was included as a control. SBS was measured using a universal testing machine, and failure modes were analyzed using a stereomicroscope. One-way analysis of variance and Tukey’s post hoc test were used for statistical analysis (p = 0.05). Results: Immediate repair groups showed significantly higher SBS than DR groups across both composite types. The highest SBS were observed with GC Modeling Liquid and hydrophobic bonding agents, particularly in the bulk-fill immediate repair groups. Phosphoric acid application alone, or in combination with self-etch adhesive, did not improve bond strength. Universal adhesives did not outperform hydrophobic agents in any condition. Direct layering without treatment resulted in the lowest bond strength, especially in delayed repair. Conclusions: Surface treatment protocol significantly affects the success of composite resin repair. Hydrophobic adhesives and GC Modeling Liquid proved to be the most effective options, especially for same-visit immediate repairs. Simplified approaches avoiding unnecessary etching or priming may offer clinically efficient solutions without compromising bond strength. Adhesives Adhesive Systems Bond Strength Composite Resins Dental Bonding Dental Restoration Repair Immediate Dental Restoration Shear Strength Figures Figure 1 Figure 2 Background Composite resin restorations are widely used in dentistry due to their conservative approach, aesthetic benefits, cost-effectiveness, and ease of repair[ 1 ]. A key factor in their success is the adhesion between resin layers, which is strongly influenced by the oxygen-inhibited layer (OIL) formed during polymerization. When resin is cured in the presence of oxygen, a superficial layer of unpolymerized monomers with a liquid-like consistency remains. During composite layering, the OIL increases the contact area between layers, enhances bonding, and facilitates the formation of an interdiffusion zone where copolymerization occurs, allowing for the development of a chemical bond between materials[ 2 ]. In various cases, such as proximal contact problems, marginal incompatibility or excessive or incorrectly applied composite layers that cause problems in achieving colour and translucency harmony of the restoration, it may be necessary to cut back newly polymerised composite resin with a bur for corrections, during which the OIL is removed. This layer is also absent when old restorations need to be repaired. The OIL has been shown to enhance bond strength by enabling covalent interaction within the polymer network[ 3 ], raising concerns about the bonding quality when new composite is applied to surfaces lacking this layer[ 4 ]. Conversely, it has been suggested that the OIL may weaken the bond due to its fragile structure[ 5 ]. On the other hand, studies have reported that even after the removal of the OIL—which is rich in resin components—from freshly cured composite, free radicals remain within the material. The stability of these radicals is influenced by multiple factors. Although unreacted methacrylate groups persist in aged composites, the number of unsaturated double bonds decreases over time, reducing the bonding potential of newly applied composite. Consequently, the bond strength in immediate repair(IR) is generally higher than in the repair of aged composites[ 6 ]. For the repair of aged restorations, interventions such as surface roughening, adhesive application, or silane treatment are commonly recommended to enhance bonding between composite layers[ 7 ]. However, it remains uncertain whether such procedures are necessary to improve bonding in the repair of freshly polymerized composite restorations. This study aims to assess the effects of various surface treatments on the shear bond strength (SBS) between composite resin layers following diamond bur roughening and the addition of a new composite layer. Comparisons will be made between freshly cured and aged composites, using two types of composite materials: bulk-fill and nanohybrid. Null Hypotheses: Surface treatments do not affect the SBS between layers of freshly poliymerized composite resins after diamond bur roughening. Surface treatments do not affect the SBS between layers of aged composite resins after diamond bur roughening. There is no difference in the effect of surface treatments on SBS between freshly polymerized and aged composite resins. There is no difference in the effect of surface treatments on SBS between bulk-fill and nanohybrid composite resins(NHC). Materials and Methods: This study, approved by the 'Selçuk University Faculty of Dentistry Non-Interventional Clinical Research Ethics Committee' on December 9, 2022, with approval number 2022/55, and conducted at the Research Center Laboratory of the Faculty of Dentistry, Selçuk University. Experimental Groups Two composite resin types were used in this study: a NHC NeoSpectra ST HV(Dentsply, Konstanz, Germany) and a bulk-fill composite resin (BFC) Tetric N-Ceram Bulk-fill(Ivoclar-Vivadent, Schaan, Liechtenstein) (Table 1). A total of 400 specimens were prepared—200 for each composite resin type. Each composite resin type was divided into 20 groups(total 40 groups): 10 groups for IR and 10 for delayed repair(DR), based on surface treatments, with 10 specimens per group (Figure 1). Table 1: Composition of the Composite Resins Used in the Study Composite Resin Material Composition Neo Spectra ST HV (Dentsply, Konstanz, Germany) Resin matrix: Methacrylate-modified polysiloxane (organically modified ceramic) dimethacrylate resin, ethyl-4 (dimethylamino) benzoate, bis(4-methylphenyl) iodinium hexafluorophosphate, Bis-EMA, UDMA, TEGDMA, Camphorquinone Fillers: Spherical, pre-polymerized SphereTEC fillers (d3,50 ≈ 15 μm), unreacted barium glass, and ytterbium fluoride, Filler content by weight: 78–80% Tetric N-Ceram Bulk Fill (Ivoclar-Vivadent, Shaan, Liechtenstein) Resin matrix: Bis-GMA, Bis-EMA, UDMA, patented photo-initiator Ivocerin® Fillers: Barium aluminum silicate glass, Ytterbium, Trifluoride, Filler content: approximately 55% (volumetric), 77% (by weight) Except for the control groups that received no surface treatment(NST), all specimens were roughened using a yellow-band knife-edge diamond bur. Following this step, different surface treatment protocols were applied depending on the materials used. These included 37% phosphoric acid(Panora 200, Imicryl, Konya, Türkiye); two universal adhesives—Single Bond Universal(3M ESPE, St. Paul, MN, USA) and Prime&Bond Universal(Dentsply/Caulk, Milford, DE, USA)—; a two-step self-etch adhesive, Clearfil SE Bond(Kuraray Dental, Tokyo, Japan); a three-step etch-and-rinse adhesive, OptiBond FL(Kerr, Orange, USA); and GC Modeling Liquid(GC Corp, Tokyo, Japan), which is a modeling resin designed to improve adaptation between layers(Table 2). Clearfil SE Bond was used in three forms: as a conventional two-step application, as primer-free, and as primer-free following phosphoric acid etching. In the "Bur + Acid + SEBond without Primer" protocol, after the diamond bur roughening, 37% phosphoric acid was applied to the surface for 15 seconds, followed by the application of adhesive resin. Table 2. Composition and Application Procedure of Adhesive Systems/Materials Used in the Study Adhesive System/Material Composition Application Procedure Single Bond Universal (3M ESPE, St Paul, MN, USA) 10-MDP phosphate monomer, dimethacrylate resin, HEMA, Vitrebond™ copolymer, fillers, ethanol, water, silane, initiator Applied by rubbing onto the surface for 20 s using an applicator. Gently air-dried for 5 s. Light-cured for 10 s. Prime&Bond Universal (Dentsply/Caulk, Milford, DE, USA) Bisphenol A-glycidyl methacrylate (Bis-GMA), urethane dimethacrylate (UDMA), triethylene glycol dimethacrylate(TEGDMA), phosphoric acid-modified acrylate resin(PENTA, MDP), initiator, stabilizers, isopropanol, water Applied by rubbing for 20 s using an applicator. Gently air-dried for 5 s. Light-cured for 10 s. Clearfil SE Bond (Kuraray Dental, Tokyo, Japan) Primer: MDP, HEMA, hydrophilic dimethacrylate, camphorquinone, water. Bond: MDP, HEMA, Bis-GMA, hydrophobic dimethacrylate, N, N diethanol p-toluidine, camphorquinone, silanized colloidal silica Primer applied by rubbing for 20 s. Gently air-dried for 5 s. Bond applied. Light-cured for 10 s. Optibond FL (Kerr, Orange, USA) Primer: HEMA, GPDM, PAMM, ethanol, water, photoinitiator. Adhesive: TEGDMA, UDMA, GPDM, HEMA, Bis-GMA, photoinitiator, fillers (SiO₂, barium aluminoborosilicate, Na₂SiF₆), bonding agent A174 (48% filler by weight) 37% phosphoric acid applied for 15 s, rinsed for 15 s, and air-dried for 5 s. Primer applied for 15 s, air-dried for 5 s. Adhesive applied. Light-cured for 10 s. GC Modeling Liquid (GC Corp, Tokyo, Japan) UDMA, 2-hydroxy-1,3 dimethacryloxypropane, 2-hydroxyethyl methacrylate, 2-hydroxy-1,3 dimethacryloxypropane triethylene glycol Applied to the composite resin surface using a brush. Panora 200 37% Etching Gel (Imicryl, Konya, Türkiye) Phosphoric acid (37%) Applied to the surface for 15 s, followed by rinsing for 15 s with water and air-dried for 5 s. DIMEI Yellow-Belted Knife-Edge Diamond Bur (Shenzhen, China) 8.0/22.0 Dia: 1.0 mm Used for roughening surfaces. In the IR groups, repairs were carried out directly after specimen fabrication. In the DR groups, specimens were stored in distilled water at 37°C for 15 days prior to repair. All specimens were then stored for an additional 24 hours in distilled water at 37 °C before undergoing shear bond strength (SBS) testing. Specimen preparation Composite disks(8 mm in diameter, 2 mm height) were fabricated using Teflon molds. Each disk was photopolymerized for 20 seconds from the top surface at 1000 mW/cm² using an LED curing unit(Valo, Ultradent Products, Inc., UT, USA) in standard power mode. Mylar strips were not employed during photopolymerization. After polymerization, the composite disks were embedded in autopolymerizing polymethyl methacrylate(PMMA)-based acrylic resin(Integra, Istanbul, Türkiye) within 1.5 cm diameter PVC pipe blocks, leaving the top surface exposed. In the IR groups(excluding those without surface treatment), the samples were roughened unidirectionally for 20 seconds with yellow-belted knife-edge diamond burs immediately after polymerization. The samples were then washed with water for 5 seconds and air-dried for 5 seconds. The diamond bur used for every 5 samples was replaced with a new one. In the DR groups(excluding those without surface treatment), the samples were incubated in distilled water at 37°C for 15 days following polymerization, after which the same procedure used for the IR groups was applied. Based on the surface treatments applied between the composite layers, 10 groups were created for both IR and DR of polymerized composite resins. Testing procedures Following the surface preparation procedures applied in accordance with the manufacturer's instructions, a polypropylene mold (2.37 mm in diameter and 2 mm in height) was placed onto the surface of the composite samples, and a repair composite, identical to the composite resin used to form the disks, was applied(Figure 2). The samples were incubated in distilled water at 37°C for 24 hours. After this incubation period, they were subjected to a SBS test using a chisel-edge cutting blade with a loading rate of 1 mm/min on a universal Instron test device(Marestek, Türkiye). SBS values in MPa were obtained using the formula: S [Shear bond strength (MPa)] = F [Force at fracture point (N)] / A [Bonding surface area (mm²)] Fracture Type Analysis After the SBS test, the composite samples were examined under a stereomicroscope(Olympus, Tokyo, Japan) at 50x magnification. Fracture types were classified as follows: Adhesive Fracture: Fracture occurring at the interface between the composite resin and the adhesive surface. Cohesive Fracture: Fracture occurring within the material itself, either in the repaired composite resin or the tooth substrate. Mixed Fracture: Fracture involving both adhesive and cohesive failure simultaneously. Statistical analysis In this in vitro study, the normality of the distribution of the samples was assessed using the Kolmogorov-Smirnov test. A one-way analysis of variance (ANOVA) was then employed to determine the differences in SBS values of composite repairs applied to NHC and BFC samples with 10 different surface treatments, both immediately and after a delayed period. Tukey's HSD test was applied to identify the groups showing significant differences (p=0.05). Statistical analyses were performed using SPSS Windows version 29.0. Results Shear Bond Strength Test Results In this study, the mean SBS values for the groups with different surface treatments applied to the specimens in IR and DR protocols are presented for NHC and BFC in Table 3. The NHC IR NST group(Control) was used as the reference value for all NHC groups in both IR and DR, while the BFC IR NST group(Control) was accepted as the reference value for all BFC groups in both IR and DR. Table 3. The mean SBS values(MPa) and standard deviations for NHC and BFC in the IR and DR groups are presented. Values within the same column that share the same lowercase letters indicate no significant difference (Tukey’s test, p < 0.05), while values within the same row that share the same uppercase letters indicate no significant difference (Tukey’s test, p < 0.05). Treatment Groups NHC IR BFC IR NHC DR BFC DR No Surface Treatment(NST) 36.62 ± 7.47 (a,A)* 40.03 ± 6.42 (a,A)* 6.16 ± 0.95 (b,B) 5.51 ± 1.78 (b,B) Only Bur(OB) 20.70 ± 4.31 (b,c,d,A) 24.75 ± 3.00 (b,e,f,g,A) 18.13 ± 1.58 (c,A) 8.24 ± 1.79 (b,B) Acid(A) 20.34 ± 3.59 (b,c,d,A) 19.85 ± 2.57 (b,c,A) 11.08 ± 2.56 (b,c,B) 7.28 ± 2.26 (b,B) SingleBond Universal(SBU) 27.66 ± 7.30 (c,d,e,f,g,A) 34.28 ± 2.79 (a,d,i,A) 27.06 ± 4.36 (d,f,h,A) 20.90 ± 4.64 (c,d,B) Prime & Bond Universal(PBU) 26.10 ± 7.20 (b,c,d,e,f,A,B) 31.20 ± 3.71 (d,e,g,h,i,A) 20.25 ± 2.43 (e,f,B) 20.43 ± 4.71 (c,d,B) SEBond P+B(SEPB) 34.23 ± 6.26 (a,g,A) 26.24 ± 4.61 (b,c,d,e,f,h,B) 20.60 ± 1.86 (e,f,B) 25.35 ± 5.66 (c,d,e,B) Acid + SEBond without Primer(ASEB) 25.12 ± 6.66 (b,c,d,e,f,A,B) 32.20 ± 3.31 (a,d,g,h,i,A) 23.37 ± 3.95 (d,e,f,A,B) 27.47 ± 5.81 (d,e,f,A,B) SEBond without Primer(SEB) 31.66 ± 5.22 (a,f,g,A) 30.02 ± 4.14 (d,e,g,h,i,A) 29.39 ± 5.03 (g,h,A) 20.28 ± 5.74 (c,d,B) Optibond FL Adhesive(OFL) 31.59 ± 4.48 (a,f,g,A,B) 34.40 ± 2.97 (a,d,i,A) 24.72 ± 4.91 (d,e,f,h,B) 26.50 ± 5.84 (d,e,f,B) GC Modeling Liquid(ML) 30.99 ± 6.13 (a,e,A,B) 36.62 ± 2.22 (a,i,A) 24.63 ± 5.39 (d,e,f,h,B) 27.84 ± 6.50 (d,e,f,B) *: In the control groups, the recommended layering technique was simulated without removing the OIL during composite restoration, and this was taken as the reference value for both repair time points. In the IR groups of NHC, SEPB, SEB, OFL, and ML demonstrated SBS values that were closest to the reference group, with no statistically significant differences. For BFC in the IR groups, ML, OFL, SBU, ASEB showed SBS values closest to the reference, without statistically significant differences. Additionally, these groups showed significantly higher SBS values than the Only Bur-treated specimens. In the NHC DR groups, all surface treatment protocols resulted in significantly lower SBS values compared to the reference, except for SEB, which showed no statistically significant difference. SEB yielded significantly higher SBS values than both SEPB and PBU groups. For BFC in the DR groups, all surface treatments resulted in significantly lower SBS values compared to the reference. When comparing IR and DR groups of NHC, significant differences favoring IR were observed in the NST, A, and SEPB groups with identical surface treatments. In contrast, SBS remained consistent between IR and DR in the OB group, indicating minimal influence of repair timing. When comparing IR and DR groups of BFC, significant differences favoring IR were observed in the NST, OB, A, SBU, PBU, SEB, and ML groups with identical surface treatments. Unlike NHC, a notable difference was observed in the Only Bur group, emphasizing the greater need for resin application in DR. When comparing NHC and BFC with the same surface treatments under IR conditions, SEPB proved significantly more effective in NHC. When comparing DR groups, NHC showed significantly higher SBS than BFC in the OB group. This suggests that BFC may require additional adhesive or resin application after cut-back with bur in DR. NST groups in IR, representing the cohesive strength of the composites, were used as reference values. SBS of the groups were calculated as percentages of these reference values (Table 4). None of the surface-treated groups reached the reference values, with ratios ranging from 13.8% to 93.4%. Table 4: The percentage ratios of SBS data for NHC and BFC in IR and DR groups relative to their reference cohesive strength values. NHC BFC IR DR IR DR NST 100% 16,8% 100% 13,8% OB 56.5% 49.5% 61.9% 20.6% A 55.5% 30.2% 49.6% 18.2% SBU 75.5% 74.0% 85.7% 52.3% PBU 71.2% 55.3% 78% 51% SEPB 93.4% 56.2% 65.6% 63.3% ASEPB 68.%6 63.8% 80.5% 68.6% SEB 86.4% 80.2% 75% 50.7% OFL 86.2% 67.5% 86% 66.2% ML 84.6% 67.3% 91.3% 69.6% Fracture Type Analysis The numerical distribution of fracture types obtained after all groups were subjected to SBS test is presented in Table 5. The highest frequency of adhesive fracture type was observed in the NHC IR A group, NHC DR NST group, and NHC DR acid group. All samples in these groups exhibited an adhesive fracture pattern. The highest frequency of cohesive fracture type was observed in the following groups: NHC IR groups: NST, SBU, PBU, SEPB, SEB, OFL; NHC DR group: SEB; BFC IR groups: SEPB, ASEB, SEB; and BFC DR groups: OFL, ML. Cohesive fracture patterns were observed in all these groups. The highest frequency of mixed fracture type was observed in the BFC DR PBU group. Table 5: Numerical Distribution of Fracture Types[Adhesive(A), Cohesive(C), Mixed(M)] Based on Composite Resin Type and Repair Timing Nanohybrid Universal Composite Resin Bulk-Fill Composite Resin Immediate Repair Delayed Repair Immediate Repair Delayed Repair Fracture Type: A C M A C M A C M A C M NST 0 10 0 10 0 0 3 5 2 9 1 0 OB 7 2 1 6 1 3 2 7 1 9 0 1 A 10 0 0 10 0 0 5 3 2 9 0 1 SBU 0 10 0 0 9 1 0 9 1 1 8 1 PBU 0 10 0 1 8 1 0 9 1 0 5 5 SEPB 0 10 0 0 8 2 0 10 0 0 8 2 ASEB 0 9 1 0 7 3 0 10 0 0 7 3 SEB 0 10 0 0 10 0 0 10 0 0 7 3 OFL 0 10 0 1 9 0 0 8 2 0 10 0 ML 0 9 1 1 8 1 0 7 3 0 10 0 Discussion In this study, the effect of various interventions on the bond strength between composite resin layers during the addition of new composite resins onto freshly cured ones, following roughening with a diamond bur (IR), was evaluated in comparison to aged composite resins(DR) for two different types of composite resins. IR groups were designed to simulate re-layering procedures performed during the same clinical visit after correcting defects. During the placement of direct composite resin restorations, clinical challenges such as contact issues, marginal discrepancies, or excess and improperly applied material affecting color and translucency may require the removal of newly polymerized composite using a bur. Diamond burs are therefore commonly used for practical and effective surface preparation in such repair procedures. In contrast, the repair of aged restorations typically involves surface roughening and the application of bonding agents to enhance interlayer adhesion[ 7 ]. However, in the context of IR, residual carbon double bonds may still remain after OIL removal, enabling bonding with the newly added composite. To investigate whether bonding agents are equally essential in IR, our study applied various bonding resins between layers after roughening with bur in both BFC and NHC. Diamond bur roughening was used in this study to simulate clinical conditions, as it has been shown to improve bond strength by creating macro- and micro-retentive features[ 8 ]. In IR protocols, the repair composite is typically matched to the substrate material; therefore, the same composite resin was used to standardize both IR and DR procedures in this study. Under ideal conditions, the SBS between composite resin layers is considered to approach the material's cohesive strength. However, the direct bonding of new resin can be significantly reduced if the surface is contaminated, polished or aged[ 9 ]. To provide a baseline for comparison, specimens with intact OIL and no surface treatment—allowing immediate layering post-polymerization—were used as the control group for both IR and DR. Bonding effectiveness can be evaluated using both in vivo and in vitro methods; however, in vitro testing is preferred for its ability to standardize conditions and control variables[ 10 ]. In this study, the SBS test—one of the most widely used methods for evaluating repair bond strength—was chosen for its clinical relevance, especially in composite resin restorations. While adhesive test results allow for comparative evaluation of bonding systems[ 10 ], direct comparison of absolute values between studies should be avoided, as bond strength results may vary by 20–50% across similar studies[ 11 ]. Several studies have shown that composite-to-composite repair SBS can reach 20–80% of the initial SBS, considering the material's cohesive strength[ 12 ] Similarly, in our study, IR groups exhibited SBS ratios of 49.6–93.4%, while DR groups showed ratios of 13.8–74%. Studies have suggested that a bond strength between 15 and 25 MPa is appropriate for composite resin repairs, as it corresponds to typical dentin–composite bond strength values and is considered clinically acceptable[ 8 , 13 ]. In this study, all IR groups achieved values within this clinically acceptable range. However, several DR groups fell below this threshold, including the NHC and BFC NST groups, NHC A group, and BFC OB and A groups. These results are consistent with previous findings and emphasize the importance of surface treatment in improving repair bond strength[ 14 , 15 ]. The ideal layering technique involves applying fresh composite directly onto the OIL of previously polymerized material to optimize interlayer bonding. While bonding can occur even in the absence of OIL[ 16 ], residual free radicals and unreacted carbon–carbon double bonds play a key role in achieving this adhesion[ 17 , 18 ]. These reactive groups remain most active within the first 24 hours after polymerization[ 17 ]. Copolymerization with these groups enhances bond strength, whereas a high degree of conversion may reduce covalent interaction[ 16 ]. Atalay et al.[ 19 ] also confirmed that unreacted acrylate groups during IR improve the bond to new composite. In line with these findings, our study showed higher SBS values in IR for all surface treatments and composite types, likely due to greater availability of unreacted double bonds. The highest SBS was observed in untreated IR groups, attributed to the presence of the OIL. In IR groups, acid etching after roughening with bur showed no additive effect. Specifically in BFC IR, acid application resulted in significantly lower SBS values compared to all resin-applied groups. Similarly, in NHC IR, applying primer before SEBond's Bond led to better outcomes than acid application. In addition, universal adhesives (SBU and PBU) demonstrated inferior performance in NHC IR groups, with SBS values not reaching those of SEPB, SEB, OFL, or ML. Notably, the PBU group exhibited significantly lower bond strength than the SEPB group. The null hypothesis stating that “Surface treatments do not affect the SBS between layers of freshly polymerized composite resins after diamond bur roughening.” was rejected. OFL and ML consistently produced bond strength values closest to the reference in both composite types. Moreover, these groups exhibited significantly higher SBS compared to specimens that underwent surface roughening with a bur alone, indicating their enhanced performance in immediate repair conditions. These findings suggest that OFL and ML may offer more clinically favorable outcomes, especially when the type of composite substrate is uncertain. In the DR groups, NHC exhibited significantly higher SBS than BFC in the OB group, suggesting that BFC may require additional adhesive or resin application following bur treatment. This is consistent with Bonstein et al.[ 20 ], who reported that diamond bur roughening improves bond strength in aged composite repair, and with Atalay et al. [ 19 ], who found that bur roughening alone is insufficient for optimal bonding in bulk-fill composites. Our findings align with the results reported by Valente et al.[ 21 ], which demonstrated that combining diamond bur roughening, phosphoric acid etching, and adhesive application significantly improves long-term repair bond strength in aged composites. The strong interfacial bond achieved with this protocol may be explained by the macro-retentive features created by diamond bur roughening, improved surface wettability, and potential chemical interaction between the substrate and repair resin facilitated by the adhesive agent[ 22 ]. In both composite types, significant differences in SBS were observed among DR groups depending on the surface treatment applied. Particularly, NST and A groups consistently exhibited the lowest SBS values, while SEBond-containing groups, OFL, and ML provided superior outcomes. These findings indicate that surface treatment selection plays a critical role in optimizing repair performance for aged composite substrates. The null hypothesis stating that “surface treatments do not affect the SBS between layers of aged composite resins after diamond bur roughening” was rejected. Composite resins are subject to hydrolytic degradation over time due to water diffusion, leading to matrix–filler interface weakening, increased porosity, and surface changes that can impair repair bond strength[ 23 ]. To simulate intraoral aging, specimens in this study were stored in distilled water for 15 days, a duration shown to reduce free radical activity and reactive methacrylate availability on the surface[ 24 ]. As the chemical reactivity of the substrate decreases over time, achieving reliable copolymerization with new resin becomes more difficult. Consequently, surface treatments are necessary to re-establish macro-, micro-, or chemical bonding between aged and fresh composites[ 25 ]. In line with previous findings, DR groups in both composite types showed lower bond strength values than IR groups. The null hypothesis stating that “There is no difference in the effect of surface treatments on SBS between freshly polymerized and aged composite resins.” was rejected. NHCs are widely used in both anterior and posterior restorations due to their favorable mechanical properties and esthetic advantages. Their nanofiller content may reduce the degree of conversion by increasing light scattering, potentially enhancing chemical bonding during IR by leaving more unreacted monomers available at the surface[ 26 ]. This could explain the superior performance of NHC compared to BFC in DR groups treated only with bur. BFCs, designed primarily for posterior use, allow for 4–5 mm increments, improving clinical efficiency. Their modified formulation promotes deeper polymerization and reduces polymerization shrinkage stress[ 27 ]. However, the high degree of conversion and more efficient photoinitiator systems in BFCs may have led to the significantly lower bond strength values observed in the OB group, where no additional resin was applied, and also in the SEPB group. This is likely due to the reduced availability of reactive methacrylate groups[ 28 ]. The null hypothesis stating that “there is no difference in the effect of surface treatments on SBS between bulk-fill and nanohybrid composite resins” was partially rejected. Consistent with previous studies[ 20 , 22 ], our results demonstrated that acid etching did not improve repair bond strength in DR and, in some cases, led to clinically unacceptable values. This observation aligns with reports indicating that acid treatment has minimal or no effect on bond strength[ 29 ]. In the NHC DR group, acid application following bur roughening resulted in a substantial reduction in bond strength. In both IR and DR of NHC, phosphoric acid application prior to SEBond without primer did not improve SBS and was even associated with a slight, though statistically insignificant, reduction. These findings support previous studies reporting that phosphoric acid provides no added benefit when used before self-etch adhesives, likely due to its limited etching capability or potential to damage the composite surface[ 19 , 30 ]. The effectiveness of intermediate resin layers in composite repair is attributed to chemical bonding with the filler or matrix components and micromechanical retention achieved through monomer infiltration into surface irregularities. Proper adhesive application enhances surface wettability and facilitates chemical interaction between aged and newly applied composites[ 31 ]. Although universal adhesives containing functional monomers such as 10-MDP and silane offer simplified application and are widely used in clinical practice [ 32 ], they did not demonstrate superior bond strength compared to other adhesive systems in this study. SingleBond Universal, which includes pre-hydrolyzed silane, showed higher—but not statistically significant—SBS than Prime&Bond in DR of NHC. These results are consistent with previous studies suggesting that silane-containing universal adhesives do not significantly improve composite repair bonding[ 33 , 34 ] In NHC IR groups, the highest SBS was achieved with the use of a primer prior to SEBond application. Consistent with our findings, Cavalcanti et al.[ 35 ] reported that two-step self-etch adhesives produced bond strengths comparable to the control in IR. However, in NHC DR and BFC IR, the use of a primer before bonding did not provide additional benefit, suggesting that an extra priming step may be unnecessary and time-consuming in these situations. Similarly, Rathke et al.[ 36 ] recommended limiting primer application in clinical repairs to cases involving dentin exposure. Modeling liquids, also known as wetting or modeling agents, are used to reduce surface tension and improve the handling of composite resins by preventing the material from sticking to shaping instruments during placement[ 37 ]. In this study, GC Modeling Liquid, used as a repair material, demonstrated high SBS in both IR and DR-particularly in BFC- and performed similarly to the control in NHC IR. Its favorable performance may be attributed to the absence of hydrophilic acidic monomers, reducing the risk of interfacial degradation between composite layers. The use of a hydrophobic, unfilled resin during composite layering has been reported to improve mechanical properties by reducing voids and interfacial defects between layers[ 38 ]. In contrast, the use of hydrophilic lubricants has been associated with inferior mechanical performance and more pronounced discoloration[ 39 ]. This may be attributed to the high monomer content and increased fluid absorption, potentially altering the superficial composition of the composite. In the present study, layering with GC Modeling Liquid after cut-back yielded favorable results, supporting its clinical applicability in restorative procedures. Notably, ML achieved the highest SBS values in both IR and DR conditions of BFCs, further supporting its effectiveness as a repair material. In both composite types and repair periods, the highest incidence of adhesive failure was observed in A and NST groups, which also showed the lowest SBS values. In contrast, cohesive failures were predominantly seen in groups where adhesive resins, particularly ML and SEBond (with or without primer), were applied, often corresponding to higher SBS. However, no direct correlation between failure mode and SBS was established, and the predominance of cohesive failures may have limited the interpretability of shear bond test results. None of the surface treatment groups achieved the SBS values observed in the control group, where the oxygen-inhibited layer (OIL) was preserved. IR resulted in significantly higher SBS than DR for both composite types. The application of bonding agents after bur roughening improved SBS, particularly in DR, while unbonded DR groups yielded clinically unacceptable values. Modeling Liquid and hydrophobic resins were among the most effective agents, and additional acid or primer application before their use proved unnecessary. Silane-containing universal adhesives did not outperform hydrophobic resins. Notably, in the DR condition, diamond bur roughening alone resulted in higher bond strength in NHC compared to BFC. This in vitro study is limited by the use of only two composite types and short-term water aging. Further investigations involving a wider range of materials, long-term aging, and clinical contamination scenarios are recommended to validate and extend these findings. Abbreviations SBS: Shear Bond Strength IR: Immediate Repair DR: Delayed Repair NHC: Nanohybrid Composite BFC: Bulk-Fill Composite ST: Surface Treatment NST: No Surface Treatment SBU: Single Bond Universal PBU: Prime&Bond Universal SEPB: Clearfil SE Bond (Two-step protocol) ASEB: Clearfil SE Bond (Acid etch + bond only) SEB: Clearfil SE Bond (Bond only, no primer) OFL: OptiBond FL ML: GC Modeling Liquid PMMA: Polymethyl Methacrylate OB: Only Bur (surface roughening with no adhesive) OIL: Oxygen-Inhibited Layer MDP-10: Methacryloyloxydecyl Dihydrogen Phosphate LED: Light-Emitting Diode PVC: Polyvinyl Chloride SPSS: Statistical Package for the Social Sciences Declarations Ethics approval and consent to participate This study was approved by the Non-Interventional Clinical Research Ethics Committee of the Faculty of Dentistry, Selçuk University (Approval No: 2022/55, Date: December 9, 2022). Written consent to participate was not applicable as this was an in vitro study. Consent for publication Not applicable. Availability of data and materials The datasets used and analyzed during the current study are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests. Funding This study was supported by the Scientific Research Projects Coordination Unit of Selçuk University (Project No: 23132005). Authors' contributions MCE contributed to the conception and design of the study, data acquisition, analysis, interpretation, and manuscript writing. NC contributed to the supervision, critical revision of the manuscript, and approval of the final version. All authors read and approved the final manuscript. Acknowledgements Not applicable. Authors' information MCE is an Assistant Professor in the Department of Restorative Dentistry at Bursa Uludağ University, Türkiye. His academic work focuses on adhesive dentistry and composite repair protocols. This study aligns with his clinical and research interest in optimizing immediate and delayed repair techniques using different surface treatments and composite systems. NC is a Professor in the Department of Restorative Dentistry at Selçuk University. Her research includes esthetic composite restorations, adhesive protocols, and surface conditioning techniques. She has extensive experience in supervising restorative dental material studies. Data availability The data and materials used in the study can be obtained by contacting thecorresponding author. Clinical trial number : not applicable. References Han I-H, Kang D-W, Chung C-H, Choe H-C, Son M-K. Effect of various intraoral repair systems on the shear bond strength of composite resin to zirconia. The journal of advanced prosthodontics. 2013;5(3):248-55. Bijelic-Donova J, Garoushi S, Lassila LV, Vallittu PK. Oxygen inhibition layer of composite resins: effects of layer thickness and surface layer treatment on the interlayer bond strength. Eur J Oral Sci. 2015;123(1):53-60. Hadi S, Tjandrawinata R, Fibryanto E. The effect of oxygen-inhibited layer and its inhibition technique on diametral tensile strength values of various nanofilled composite resin types. Journal of International Oral Health. 2024;16(2):150-7. Velazquez E, Vaidyanathan J, Vaidyanathan TK, Houpt M, Shey Z, Von Hagen S. Effect of primer solvent and curing mode on dentin shear bond strength and interface morphology. Quintessence international. 2003;34(7). Ghivari S, Chandak M, Manvar N. Role of oxygen inhibited layer on shear bond strength of composites. J Conserv Dent. 2010;13(1):39-41. Özcan M, Pekkan G. Effect of different adhesion strategies on bond strength of resin composite to composite-dentin complex. Operative dentistry. 2013;38(1):63-72. Swift Jr E, LeValley B, Boyer D. Evaluation of new methods for composite repair. Dental Materials. 1992;8(6):362-5. Tabatabaei , Alizade Y, Taalim S. Effect of various surface treatment on repair strength of composite resin. 2004. Mitsaki-Matsou H, Karanika-Kouma A, Papadoyiannis Y, Theodoridou-Pahine S. An in vitro study of the tensile strength of composite resins repaired with the same or another composite resin. Quintessence international. 1991;22(6). De Munck J, Van Landuyt K, Peumans M, Poitevin A, Lambrechts P, Braem M, et al. A critical review of the durability of adhesion to tooth tissue: methods and results. J Dent Res. 2005;84(2):118-32. Scherrer SS, Cesar PF, Swain MV. Direct comparison of the bond strength results of the different test methods: a critical literature review. Dental Materials. 2010;26(2):e78-e93. Frankenberger R, Kramer N, Sindel J. Repair strength of etched vs silica-coated metal-ceramic and all-ceramic restorations. Oper Dent. 2000;25(3):209-15. Teixeira EC, Bayne SC, Thompson JY, Ritter AV, Swift EJ. Shear bond strength of self-etching bonding systems in combination with various composites used for repairing aged composites. Journal of Adhesive Dentistry. 2005;7(2). Rinastiti M, Özcan M, Siswomihardjo W, Busscher HJ. Immediate repair bond strengths of microhybrid, nanohybrid and nanofilled composites after different surface treatments. Journal of dentistry. 2010;38(1):29-38. da Costa TRF, Serrano AM, Atman APF, Loguercio AD, Reis A. Durability of composite repair using different surface treatments. Journal of Dentistry. 2012;40(6):513-21. Lucena-Martín C, González-López S, de Mondelo JMN-R. The effect of various surface treatments and bonding agents on the repaired strength of heat-treated composites. The Journal of prosthetic dentistry. 2001;86(5):481-8. El-Deeb HA, Ghalab RM, Akah MME, Mobarak EH. Repair bond strength of dual-cured resin composite core buildup materials. Journal of advanced research. 2016;7(2):263-9. Kholief EA, Mahmoud ESM, El Chabrawy SM. Shear bond strength for immediate and delayed repair of composite with microhybrid and nanohybrid resins using different bonding agents. Alexandria Dental Journal. 2020;45(2):104-10. Atalay C, Yazici AR, Ozgunaltay G. Bond strengths of bulk-fill resin composite repairs: effect of different surface treatment protocols in vitro. Journal of Adhesion Science and Technology. 2018;32(9):921-30. Bonstein T, Garlapo D, John Jr D, Bush PJ. Evaluation of varied repair protocols applied to aged composite resin. Journal of Adhesive Dentistry. 2005;7(1). Valente LL, Sarkis-Onofre R, Goncalves AP, Fernandez E, Loomans B, Moraes RR. Repair bond strength of dental composites: systematic review and meta-analysis. International Journal of Adhesion and Adhesives. 2016;69:15-26. Fawzy AS, El-Askary FS, Amer MA. Effect of surface treatments on the tensile bond strength of repaired water-aged anterior restorative micro-fine hybrid resin composite. Journal of dentistry. 2008;36(12):969-76. Souza MOd, Leitune VCB, Rodrigues SB, Samuel SMW, Collares FM. One-year aging effects on microtensile bond strengths of composite and repairs with different surface treatments. Brazilian oral research. 2017;31:e4. Garcia D, Yaman P, Dennison J, Neiva G. Polymerization shrinkage and depth of cure of bulk fill flowable composite resins. Operative dentistry. 2014;39(4):441-8. Loomans BA, Cardoso MV, Roeters F, Opdam N, De Munck J, Huysmans M, et al. Is there one optimal repair technique for all composites? Dental Materials. 2011;27(7):701-9. Bayne SC. Dental biomaterials: where are we and where are we going? Journal of dental education. 2005;69(5):571-85. Tarle Z, Attin T, Marovic D, Andermatt L, Ristic M, Tauböck T. Influence of irradiation time on subsurface degree of conversion and microhardness of high-viscosity bulk-fill resin composites. Clinical oral investigations. 2015;19:831-40. Ogunyinka A, Palin W, Shortall A, Marquis P. Photoinitiation chemistry affects light transmission and degree of conversion of curing experimental dental resin composites. Dental Materials. 2007;23(7):807-13. Ozcan M, Barbosa SH, Melo RM, Galhano GA, Bottino MA. Effect of surface conditioning methods on the microtensile bond strength of resin composite to composite after aging conditions. Dent Mater. 2007;23(10):1276-82. Akgül S, Kedici Alp C, Bala O. Repair potential of a bulk‐fill resin composite: Effect of different surface‐treatment protocols. European Journal of Oral Sciences. 2021;129(6):e12814. Brum RT, Vieira S, Freire A, Mazur RF, De Souza EM, Rached RN. Effect of organic solvents compared to sandblasting on the repair bond strength of nanohybrid and nanofilled composite resins. Indian Journal of Dental Research. 2017;28(4):433. Alex G. Universal adhesives: the next evolution in adhesive dentistry. Compend Contin Educ Dent. 2015;36(1):15-26. Silva CLd, Scherer MM, Mendes LT, Casagrande L, Leitune VCB, Lenzi TL. Does use of silane-containing universal adhesive eliminate the need for silane application in direct composite repair? Brazilian Oral Research. 2020;34. Stape THS, Tulkki O, Salim IA, Jamal KN, Mutluay MM, Tezvergil-Mutluay A. Composite repair: On the fatigue strength of universal adhesives. dental materials. 2022;38(2):231-41. Cavalcanti AN, De Lima AF, Peris AR, Mitsui FHO, Marchi GM. Effect of surface treatments and bonding agents on the bond strength of repaired composites. Journal of Esthetic and Restorative Dentistry. 2007;19(2):90-8. Rathke A, Tymina Y, Haller B. Effect of different surface treatments on the composite–composite repair bond strength. Clinical Oral Investigations. 2009;13(3):317-23. Kutuk ZB, Erden E, Aksahin DL, Durak ZE, Dulda AC. Influence of modeling agents on the surface properties of an esthetic nano-hybrid composite. Restorative Dentistry & Endodontics. 2020;45(2). Muenchow EA, Sedrez-Porto JA, Piva E, Pereira-Cenci T, Cenci MS. Use of dental adhesives as modeler liquid of resin composites. Dental Materials. 2016;32(4):570-7. Paolone G, Mazzitelli C, Josic U, Scotti N, Gherlone E, Cantatore G, et al. Modeling Liquids and Resin-Based Dental Composite Materials—A Scoping Review. Materials. 2022;15(11):3759. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 15 Dec, 2025 Read the published version in BMC Oral Health → Version 1 posted Editorial decision: Revision requested 05 Nov, 2025 Reviews received at journal 22 Oct, 2025 Reviews received at journal 11 Oct, 2025 Reviews received at journal 10 Oct, 2025 Reviewers agreed at journal 06 Oct, 2025 Reviewers agreed at journal 04 Oct, 2025 Reviewers agreed at journal 03 Oct, 2025 Reviewers invited by journal 03 Oct, 2025 Editor invited by journal 01 Sep, 2025 Editor assigned by journal 29 Aug, 2025 Submission checks completed at journal 29 Aug, 2025 First submitted to journal 28 Aug, 2025 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. 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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-7482603","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":528794762,"identity":"8faf4fc2-ff5f-4c88-97f7-bd6b66069a2b","order_by":0,"name":"Murat Can 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14:51:56","extension":"html","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":131102,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7482603/v1/8a7c73ee76de756ff1de7a0e.html"},{"id":93696289,"identity":"810709fd-4458-47b8-a892-c68ff9b89191","added_by":"auto","created_at":"2025-10-16 14:51:55","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":127494,"visible":true,"origin":"","legend":"\u003cp\u003eStudy design and grouping of composite disc samples.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7482603/v1/b34265a21eedd2920adadd7f.png"},{"id":93696290,"identity":"608cacae-1238-4ce6-bbd4-2f5b03a894eb","added_by":"auto","created_at":"2025-10-16 14:51:55","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1030164,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic representation of the shear bond strength test.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7482603/v1/c31d57896e5a0e9718755b01.png"},{"id":98813997,"identity":"6a97efc6-af74-4319-9375-bbac707fc32d","added_by":"auto","created_at":"2025-12-22 16:09:15","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1784190,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7482603/v1/8c063a20-9fa1-4a15-8e64-a78d53e52336.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Does Composite Repair Time Affect Repair Protocol, Immediate or Delayed?","fulltext":[{"header":"Background","content":"\u003cp\u003eComposite resin restorations are widely used in dentistry due to their conservative approach, aesthetic benefits, cost-effectiveness, and ease of repair[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. A key factor in their success is the adhesion between resin layers, which is strongly influenced by the oxygen-inhibited layer (OIL) formed during polymerization. When resin is cured in the presence of oxygen, a superficial layer of unpolymerized monomers with a liquid-like consistency remains. During composite layering, the OIL increases the contact area between layers, enhances bonding, and facilitates the formation of an interdiffusion zone where copolymerization occurs, allowing for the development of a chemical bond between materials[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn various cases, such as proximal contact problems, marginal incompatibility or excessive or incorrectly applied composite layers that cause problems in achieving colour and translucency harmony of the restoration, it may be necessary to cut back newly polymerised composite resin with a bur for corrections, during which the OIL is removed. This layer is also absent when old restorations need to be repaired. The OIL has been shown to enhance bond strength by enabling covalent interaction within the polymer network[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], raising concerns about the bonding quality when new composite is applied to surfaces lacking this layer[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Conversely, it has been suggested that the OIL may weaken the bond due to its fragile structure[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOn the other hand, studies have reported that even after the removal of the OIL\u0026mdash;which is rich in resin components\u0026mdash;from freshly cured composite, free radicals remain within the material. The stability of these radicals is influenced by multiple factors. Although unreacted methacrylate groups persist in aged composites, the number of unsaturated double bonds decreases over time, reducing the bonding potential of newly applied composite. Consequently, the bond strength in immediate repair(IR) is generally higher than in the repair of aged composites[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. For the repair of aged restorations, interventions such as surface roughening, adhesive application, or silane treatment are commonly recommended to enhance bonding between composite layers[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. However, it remains uncertain whether such procedures are necessary to improve bonding in the repair of freshly polymerized composite restorations.\u003c/p\u003e\u003cp\u003eThis study aims to assess the effects of various surface treatments on the shear bond strength (SBS) between composite resin layers following diamond bur roughening and the addition of a new composite layer. Comparisons will be made between freshly cured and aged composites, using two types of composite materials: bulk-fill and nanohybrid.\u003c/p\u003e\u003cp\u003eNull Hypotheses:\u003c/p\u003e\u003cp\u003e\u003col\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eSurface treatments do not affect the SBS between layers of freshly poliymerized composite resins after diamond bur roughening.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eSurface treatments do not affect the SBS between layers of aged composite resins after diamond bur roughening.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eThere is no difference in the effect of surface treatments on SBS between freshly polymerized and aged composite resins.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eThere is no difference in the effect of surface treatments on SBS between bulk-fill and nanohybrid composite resins(NHC).\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003c/ol\u003e\u003c/p\u003e"},{"header":"Materials and Methods:","content":"\u003cp\u003eThis study, approved by the \u0026apos;Sel\u0026ccedil;uk University Faculty of Dentistry Non-Interventional Clinical Research Ethics Committee\u0026apos; on December 9, 2022, with approval number 2022/55, and conducted at the Research Center Laboratory of the Faculty of Dentistry, Sel\u0026ccedil;uk University.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eExperimental Groups\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eTwo composite resin types were used in this study: a NHC NeoSpectra ST HV(Dentsply, Konstanz, Germany) and a bulk-fill composite resin (BFC) Tetric N-Ceram Bulk-fill(Ivoclar-Vivadent, Schaan, Liechtenstein) (Table 1). A total of 400 specimens were prepared\u0026mdash;200 for each composite resin type. Each composite resin type was divided into 20 groups(total 40 groups): 10 groups for IR and 10 for delayed repair(DR), based on surface treatments, with 10 specimens per group (Figure 1).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1:\u0026nbsp;\u003c/strong\u003eComposition of the Composite Resins Used in the Study\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eComposite Resin Material\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eComposition\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eNeo Spectra ST HV (Dentsply, Konstanz, Germany)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eResin matrix:\u003c/strong\u003e Methacrylate-modified polysiloxane (organically modified ceramic) dimethacrylate resin, ethyl-4 (dimethylamino) benzoate, bis(4-methylphenyl) iodinium hexafluorophosphate, Bis-EMA, UDMA, TEGDMA, Camphorquinone\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eFillers:\u003c/strong\u003e Spherical, pre-polymerized SphereTEC fillers (d3,50 \u0026asymp; 15 \u0026mu;m), unreacted barium glass, and ytterbium fluoride, Filler content by weight: 78\u0026ndash;80%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTetric N-Ceram Bulk Fill (Ivoclar-Vivadent, Shaan, Liechtenstein)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eResin matrix:\u003c/strong\u003e Bis-GMA, Bis-EMA, UDMA, patented photo-initiator Ivocerin\u0026reg;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eFillers:\u003c/strong\u003e Barium aluminum silicate glass, Ytterbium, Trifluoride, Filler content: approximately 55% (volumetric), 77% (by weight)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eExcept for the control groups that received no surface treatment(NST), all specimens were roughened using a yellow-band knife-edge diamond bur. Following this step, different surface treatment protocols were applied depending on the materials used. These included 37% phosphoric acid(Panora 200, Imicryl, Konya, T\u0026uuml;rkiye); two universal adhesives\u0026mdash;Single Bond Universal(3M ESPE, St. Paul, MN, USA) and Prime\u0026amp;Bond Universal(Dentsply/Caulk, Milford, DE, USA)\u0026mdash;; a two-step self-etch adhesive, Clearfil SE Bond(Kuraray Dental, Tokyo, Japan); a three-step etch-and-rinse adhesive, OptiBond FL(Kerr, Orange, USA); and GC Modeling Liquid(GC Corp, Tokyo, Japan), which is a modeling resin designed to improve adaptation between layers(Table 2). Clearfil SE Bond was used in three forms: as a conventional two-step application, as primer-free, and as primer-free following phosphoric acid etching. In the \u0026quot;Bur + Acid + SEBond without Primer\u0026quot; protocol, after the diamond bur roughening, 37% phosphoric acid was applied to the surface for 15 seconds, followed by the application of adhesive resin.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2.\u0026nbsp;\u003c/strong\u003eComposition and Application Procedure of Adhesive Systems/Materials Used in the Study\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAdhesive System/Material\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eComposition\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eApplication Procedure\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSingle Bond Universal (3M ESPE, St Paul, MN, USA)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003e10-MDP phosphate monomer, dimethacrylate resin, HEMA, Vitrebond\u0026trade; copolymer, fillers, ethanol, water, silane, initiator\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003eApplied by rubbing onto the surface for 20 s using an applicator. Gently air-dried for 5 s. Light-cured for 10 s.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePrime\u0026amp;Bond Universal (Dentsply/Caulk, Milford, DE, USA)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003eBisphenol A-glycidyl methacrylate (Bis-GMA), urethane dimethacrylate (UDMA), triethylene glycol dimethacrylate(TEGDMA), phosphoric acid-modified acrylate resin(PENTA, MDP), initiator, stabilizers, isopropanol, water\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003eApplied by rubbing for 20 s using an applicator. Gently air-dried for 5 s. Light-cured for 10 s.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eClearfil SE Bond (Kuraray Dental, Tokyo, Japan)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePrimer:\u003c/strong\u003e MDP, HEMA, hydrophilic dimethacrylate, camphorquinone, water.\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eBond:\u003c/strong\u003e MDP, HEMA, Bis-GMA, hydrophobic dimethacrylate, N, N diethanol p-toluidine, camphorquinone, silanized colloidal silica\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003ePrimer applied by rubbing for 20 s. Gently air-dried for 5 s. Bond applied. Light-cured for 10 s.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOptibond FL (Kerr, Orange, USA)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePrimer:\u003c/strong\u003e HEMA, GPDM, PAMM, ethanol, water, photoinitiator. \u003cstrong\u003eAdhesive:\u003c/strong\u003e TEGDMA, UDMA, GPDM, HEMA, Bis-GMA, photoinitiator, fillers (SiO₂, barium aluminoborosilicate, Na₂SiF₆), bonding agent A174 (48% filler by weight)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e37% phosphoric acid applied for 15 s, rinsed for 15 s, and air-dried for 5 s. Primer applied for 15 s, air-dried for 5 s. Adhesive applied. Light-cured for 10 s.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGC Modeling Liquid\u003c/strong\u003e \u003cstrong\u003e(GC Corp, Tokyo, Japan)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003e\u0026nbsp;UDMA, 2-hydroxy-1,3 dimethacryloxypropane, 2-hydroxyethyl methacrylate, 2-hydroxy-1,3 dimethacryloxypropane triethylene glycol\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003eApplied to the composite resin surface using a brush.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePanora 200 37% Etching Gel (Imicryl, Konya, T\u0026uuml;rkiye)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003ePhosphoric acid (37%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003eApplied to the surface for 15 s, followed by rinsing for 15 s with water and air-dried for 5 s.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDIMEI Yellow-Belted Knife-Edge Diamond Bur\u003c/strong\u003e \u003cstrong\u003e(Shenzhen, China)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003e8.0/22.0 Dia: 1.0 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003eUsed for roughening surfaces.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eIn the IR groups, repairs were carried out directly after specimen fabrication. In the DR groups, specimens were stored in distilled water at 37\u0026deg;C for 15 days prior to repair. All specimens were then stored for an additional 24 hours in distilled water at 37 \u0026deg;C before undergoing shear bond strength (SBS) testing.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eSpecimen preparation\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eComposite disks(8 mm in diameter, 2 mm height) were fabricated using Teflon molds. Each disk was photopolymerized for 20 seconds from the top surface at 1000 mW/cm\u0026sup2; using an LED curing unit(Valo, Ultradent Products, Inc., UT, USA) in standard power mode. Mylar strips were not employed during photopolymerization. After polymerization, the composite disks were embedded in autopolymerizing polymethyl methacrylate(PMMA)-based acrylic resin(Integra, Istanbul, T\u0026uuml;rkiye) within 1.5 cm diameter PVC pipe blocks, leaving the top surface exposed.\u003c/p\u003e\n\u003cp\u003eIn the IR groups(excluding those without surface treatment), the samples were roughened unidirectionally for 20 seconds with yellow-belted knife-edge diamond burs immediately after polymerization. The samples were then washed with water for 5 seconds and air-dried for 5 seconds. The diamond bur used for every 5 samples was replaced with a new one.\u003c/p\u003e\n\u003cp\u003eIn the DR groups(excluding those without surface treatment), the samples were incubated in distilled water at 37\u0026deg;C for 15 days following polymerization, after which the same procedure used for the IR groups was applied.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eBased on the surface treatments applied between the composite layers, 10 groups were created for both IR and DR of polymerized composite resins.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eTesting procedures\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eFollowing the surface preparation procedures applied in accordance with the manufacturer\u0026apos;s instructions, a polypropylene mold (2.37 mm in diameter and 2 mm in height) was placed onto the surface of the composite samples, and a repair composite, identical to the composite resin used to form the disks, was applied(Figure 2).\u003c/p\u003e\n\u003cp\u003eThe samples were incubated in distilled water at 37\u0026deg;C for 24 hours. After this incubation period, they were subjected to a SBS test using a chisel-edge cutting blade with a loading rate of 1 mm/min on a universal Instron test device(Marestek, T\u0026uuml;rkiye). SBS values in MPa were obtained using the formula: S [Shear bond strength (MPa)] = F [Force at fracture point (N)] / A [Bonding surface area (mm\u0026sup2;)]\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFracture Type Analysis\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAfter the SBS test, the composite samples were examined under a stereomicroscope(Olympus, Tokyo, Japan) at 50x magnification. Fracture types were classified as follows: Adhesive Fracture: Fracture occurring at the interface between the composite resin and the adhesive surface. Cohesive Fracture: Fracture occurring within the material itself, either in the repaired composite resin or the tooth substrate. Mixed Fracture: Fracture involving both adhesive and cohesive failure simultaneously.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eStatistical analysis\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eIn this in vitro study, the normality of the distribution of the samples was assessed using the Kolmogorov-Smirnov test. A one-way analysis of variance (ANOVA) was then employed to determine the differences in SBS values of composite repairs applied to NHC and BFC samples with 10 different surface treatments, both immediately and after a delayed period. Tukey\u0026apos;s HSD test was applied to identify the groups showing significant differences (p=0.05). Statistical analyses were performed using SPSS Windows version 29.0.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eShear Bond Strength Test Results\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this study, the mean SBS values for the groups with different surface treatments applied to the specimens in IR and DR protocols are presented for NHC and BFC in Table 3. \u0026nbsp;The NHC IR NST group(Control) was used as the reference value for all NHC groups in both IR and DR, while the BFC IR NST group(Control) was accepted as the reference value for all BFC groups in both IR and DR.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3.\u0026nbsp;\u003c/strong\u003eThe mean SBS values(MPa) and standard deviations for NHC and BFC in the IR and DR groups are presented. Values within the same column that share the same lowercase letters indicate no significant difference (Tukey\u0026rsquo;s test, p \u0026lt; 0.05), while values within the same row that share the same uppercase letters indicate no significant difference (Tukey\u0026rsquo;s test, p \u0026lt; 0.05).\u003c/p\u003e\n\u003cdiv align=\"\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"599\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 137px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTreatment Groups\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNHC IR\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBFC IR\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNHC DR\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBFC DR\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 137px;\"\u003e\n \u003cp\u003eNo Surface Treatment(NST)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e36.62 \u0026plusmn; 7.47 (a,A)*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e40.03 \u0026plusmn; 6.42 (a,A)*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003e6.16 \u0026plusmn; 0.95 (b,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e5.51 \u0026plusmn; 1.78 (b,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 137px;\"\u003e\n \u003cp\u003eOnly Bur(OB)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e20.70 \u0026plusmn; 4.31 (b,c,d,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e24.75 \u0026plusmn; 3.00 (b,e,f,g,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003e18.13 \u0026plusmn; 1.58 (c,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e8.24 \u0026plusmn; 1.79 (b,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 137px;\"\u003e\n \u003cp\u003eAcid(A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e20.34 \u0026plusmn; 3.59 (b,c,d,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e19.85 \u0026plusmn; 2.57 (b,c,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003e11.08 \u0026plusmn; 2.56 (b,c,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e7.28 \u0026plusmn; 2.26 (b,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 137px;\"\u003e\n \u003cp\u003eSingleBond Universal(SBU)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e27.66 \u0026plusmn; 7.30 (c,d,e,f,g,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e34.28 \u0026plusmn; 2.79 (a,d,i,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003e27.06 \u0026plusmn; 4.36 (d,f,h,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e20.90 \u0026plusmn; 4.64 (c,d,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 137px;\"\u003e\n \u003cp\u003ePrime \u0026amp; Bond Universal(PBU)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e26.10 \u0026plusmn; 7.20 (b,c,d,e,f,A,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e31.20 \u0026plusmn; 3.71 (d,e,g,h,i,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003e20.25 \u0026plusmn; 2.43 (e,f,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e20.43 \u0026plusmn; 4.71 (c,d,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 137px;\"\u003e\n \u003cp\u003eSEBond P+B(SEPB)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e34.23 \u0026plusmn; 6.26 (a,g,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e26.24 \u0026plusmn; 4.61 (b,c,d,e,f,h,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003e20.60 \u0026plusmn; 1.86 (e,f,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e25.35 \u0026plusmn; 5.66 (c,d,e,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 137px;\"\u003e\n \u003cp\u003eAcid + SEBond without Primer(ASEB)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e25.12 \u0026plusmn; 6.66 (b,c,d,e,f,A,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e32.20 \u0026plusmn; 3.31 (a,d,g,h,i,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003e23.37 \u0026plusmn; 3.95 (d,e,f,A,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e27.47 \u0026plusmn; 5.81 (d,e,f,A,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 137px;\"\u003e\n \u003cp\u003eSEBond without Primer(SEB)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e31.66 \u0026plusmn; 5.22 (a,f,g,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e30.02 \u0026plusmn; 4.14 (d,e,g,h,i,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003e29.39 \u0026plusmn; 5.03 (g,h,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e20.28 \u0026plusmn; 5.74 (c,d,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 137px;\"\u003e\n \u003cp\u003eOptibond FL Adhesive(OFL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e31.59 \u0026plusmn; 4.48 (a,f,g,A,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e34.40 \u0026plusmn; 2.97 (a,d,i,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003e24.72 \u0026plusmn; 4.91 (d,e,f,h,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e26.50 \u0026plusmn; 5.84 (d,e,f,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 137px;\"\u003e\n \u003cp\u003eGC Modeling Liquid(ML)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e30.99 \u0026plusmn; 6.13 (a,e,A,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e36.62 \u0026plusmn; 2.22 (a,i,A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003e24.63 \u0026plusmn; 5.39 (d,e,f,h,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 117px;\"\u003e\n \u003cp\u003e27.84 \u0026plusmn; 6.50 (d,e,f,B)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cem\u003e*: In the control groups, the recommended layering technique was simulated without removing the OIL during composite restoration, and this was taken as the reference value for both repair time points.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eIn the IR groups of NHC, SEPB, SEB, OFL, and ML demonstrated SBS values that were closest to the reference group, with no statistically significant differences. For BFC in the IR groups, ML, OFL, SBU, ASEB showed SBS values closest to the reference, without statistically significant differences. Additionally, these groups showed significantly higher SBS values than the Only Bur-treated specimens.\u003c/p\u003e\n\u003cp\u003eIn the NHC DR groups, all surface treatment protocols resulted in significantly lower SBS values compared to the reference, except for SEB, which showed no statistically significant difference. SEB yielded significantly higher SBS values than both SEPB and PBU groups. For BFC in the DR groups, all surface treatments resulted in significantly lower SBS values compared to the reference.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWhen comparing IR and DR groups of NHC, significant differences favoring IR were observed in the NST, A, and SEPB groups with identical surface treatments. In contrast, SBS remained consistent between IR and DR in the OB group, indicating minimal influence of repair timing.\u003c/p\u003e\n\u003cp\u003eWhen comparing IR and DR groups of BFC, significant differences favoring IR were observed in the NST, OB, A, SBU, PBU, SEB, and ML groups with identical surface treatments. Unlike NHC, a notable difference was observed in the Only Bur group, emphasizing the greater need for resin application in DR.\u003c/p\u003e\n\u003cp\u003eWhen comparing NHC and BFC with the same surface treatments under IR conditions, SEPB proved significantly more effective in NHC. When comparing DR groups, NHC showed significantly higher SBS than BFC in the OB group. This suggests that BFC may require additional adhesive or resin application after cut-back with bur in DR.\u003c/p\u003e\n\u003cp\u003eNST groups in IR, representing the cohesive strength of the composites, were used as reference values. SBS of the groups were calculated as percentages of these reference values (Table 4). None of the surface-treated groups reached the reference values, with ratios ranging from 13.8% to 93.4%.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4:\u003c/strong\u003e The percentage ratios of SBS data for NHC and BFC in IR and DR groups relative to their reference cohesive strength values.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"\" width=\"604\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003eNHC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eBFC\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003eIR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003eDR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 23px;\"\u003e\n \u003cp\u003eIR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003eDR\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eNST\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e100%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e16,8%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 23px;\"\u003e\n \u003cp\u003e100%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e13,8%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eOB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e56.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e49.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 23px;\"\u003e\n \u003cp\u003e61.9%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e20.6%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e55.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e30.2%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 23px;\"\u003e\n \u003cp\u003e49.6%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e18.2%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eSBU\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e75.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e74.0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 23px;\"\u003e\n \u003cp\u003e85.7%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e52.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003ePBU\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e71.2%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e55.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 23px;\"\u003e\n \u003cp\u003e78%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e51%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eSEPB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e93.4%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e56.2%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 23px;\"\u003e\n \u003cp\u003e65.6%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e63.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eASEPB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e68.%6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e63.8%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 23px;\"\u003e\n \u003cp\u003e80.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e68.6%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eSEB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e86.4%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e80.2%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 23px;\"\u003e\n \u003cp\u003e75%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e50.7%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eOFL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e86.2%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e67.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 23px;\"\u003e\n \u003cp\u003e86%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e66.2%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 189px;\"\u003e\n \u003cp\u003eML\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e84.6%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e67.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 23px;\"\u003e\n \u003cp\u003e91.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e69.6%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eFracture Type Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe numerical distribution of fracture types obtained after all groups were subjected to SBS test is presented in Table 5.\u003c/p\u003e\n\u003cp\u003eThe highest frequency of adhesive fracture type was observed in the NHC IR A group, NHC DR NST group, and NHC DR acid group. All samples in these groups exhibited an adhesive fracture pattern. The highest frequency of cohesive fracture type was observed in the following groups: NHC IR groups: NST, SBU, PBU, SEPB, SEB, OFL; NHC DR group: SEB; BFC IR groups: SEPB, ASEB, SEB; and BFC DR groups: OFL, ML. Cohesive fracture patterns were observed in all these groups. The highest frequency of mixed fracture type was observed in the BFC DR PBU group.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 5:\u003c/strong\u003e Numerical Distribution of Fracture Types[Adhesive(A), Cohesive(C), Mixed(M)] Based on Composite Resin Type and Repair Timing\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"\" width=\"586\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"6\" valign=\"top\" style=\"width: 203px;\"\u003e\n \u003cp\u003eNanohybrid Universal Composite Resin\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"6\" valign=\"top\" style=\"width: 250px;\"\u003e\n \u003cp\u003eBulk-Fill Composite Resin\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 102px;\"\u003e\n \u003cp\u003eImmediate Repair\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 102px;\"\u003e\n \u003cp\u003eDelayed Repair\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 102px;\"\u003e\n \u003cp\u003eImmediate Repair\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 148px;\"\u003e\n \u003cp\u003eDelayed Repair\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eFracture Type:\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 80px;\"\u003e\n \u003cp\u003eM\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eNST\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 80px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eOB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 80px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 80px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eSBU\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 80px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003ePBU\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 80px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eSEPB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 80px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eASEB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 80px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eSEB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 80px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eOFL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 80px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003eML\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 80px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, the effect of various interventions on the bond strength between composite resin layers during the addition of new composite resins onto freshly cured ones, following roughening with a diamond bur (IR), was evaluated in comparison to aged composite resins(DR) for two different types of composite resins. IR groups were designed to simulate re-layering procedures performed during the same clinical visit after correcting defects.\u003c/p\u003e\u003cp\u003eDuring the placement of direct composite resin restorations, clinical challenges such as contact issues, marginal discrepancies, or excess and improperly applied material affecting color and translucency may require the removal of newly polymerized composite using a bur. Diamond burs are therefore commonly used for practical and effective surface preparation in such repair procedures. In contrast, the repair of aged restorations typically involves surface roughening and the application of bonding agents to enhance interlayer adhesion[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. However, in the context of IR, residual carbon double bonds may still remain after OIL removal, enabling bonding with the newly added composite. To investigate whether bonding agents are equally essential in IR, our study applied various bonding resins between layers after roughening with bur in both BFC and NHC.\u003c/p\u003e\u003cp\u003eDiamond bur roughening was used in this study to simulate clinical conditions, as it has been shown to improve bond strength by creating macro- and micro-retentive features[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn IR protocols, the repair composite is typically matched to the substrate material; therefore, the same composite resin was used to standardize both IR and DR procedures in this study.\u003c/p\u003e\u003cp\u003eUnder ideal conditions, the SBS between composite resin layers is considered to approach the material's cohesive strength. However, the direct bonding of new resin can be significantly reduced if the surface is contaminated, polished or aged[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. To provide a baseline for comparison, specimens with intact OIL and no surface treatment\u0026mdash;allowing immediate layering post-polymerization\u0026mdash;were used as the control group for both IR and DR.\u003c/p\u003e\u003cp\u003eBonding effectiveness can be evaluated using both in vivo and in vitro methods; however, in vitro testing is preferred for its ability to standardize conditions and control variables[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. In this study, the SBS test\u0026mdash;one of the most widely used methods for evaluating repair bond strength\u0026mdash;was chosen for its clinical relevance, especially in composite resin restorations. While adhesive test results allow for comparative evaluation of bonding systems[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], direct comparison of absolute values between studies should be avoided, as bond strength results may vary by 20\u0026ndash;50% across similar studies[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eSeveral studies have shown that composite-to-composite repair SBS can reach 20\u0026ndash;80% of the initial SBS, considering the material's cohesive strength[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] Similarly, in our study, IR groups exhibited SBS ratios of 49.6\u0026ndash;93.4%, while DR groups showed ratios of 13.8\u0026ndash;74%.\u003c/p\u003e\u003cp\u003eStudies have suggested that a bond strength between 15 and 25 MPa is appropriate for composite resin repairs, as it corresponds to typical dentin\u0026ndash;composite bond strength values and is considered clinically acceptable[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. In this study, all IR groups achieved values within this clinically acceptable range. However, several DR groups fell below this threshold, including the NHC and BFC NST groups, NHC A group, and BFC OB and A groups. These results are consistent with previous findings and emphasize the importance of surface treatment in improving repair bond strength[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe ideal layering technique involves applying fresh composite directly onto the OIL of previously polymerized material to optimize interlayer bonding. While bonding can occur even in the absence of OIL[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], residual free radicals and unreacted carbon\u0026ndash;carbon double bonds play a key role in achieving this adhesion[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. These reactive groups remain most active within the first 24 hours after polymerization[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Copolymerization with these groups enhances bond strength, whereas a high degree of conversion may reduce covalent interaction[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Atalay et al.[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] also confirmed that unreacted acrylate groups during IR improve the bond to new composite. In line with these findings, our study showed higher SBS values in IR for all surface treatments and composite types, likely due to greater availability of unreacted double bonds. The highest SBS was observed in untreated IR groups, attributed to the presence of the OIL.\u003c/p\u003e\u003cp\u003eIn IR groups, acid etching after roughening with bur showed no additive effect. Specifically in BFC IR, acid application resulted in significantly lower SBS values compared to all resin-applied groups. Similarly, in NHC IR, applying primer before SEBond's Bond led to better outcomes than acid application. In addition, universal adhesives (SBU and PBU) demonstrated inferior performance in NHC IR groups, with SBS values not reaching those of SEPB, SEB, OFL, or ML. Notably, the PBU group exhibited significantly lower bond strength than the SEPB group.\u003c/p\u003e\u003cp\u003eThe null hypothesis stating that \u0026ldquo;Surface treatments do not affect the SBS between layers of freshly polymerized composite resins after diamond bur roughening.\u0026rdquo; was rejected. OFL and ML consistently produced bond strength values closest to the reference in both composite types. Moreover, these groups exhibited significantly higher SBS compared to specimens that underwent surface roughening with a bur alone, indicating their enhanced performance in immediate repair conditions. These findings suggest that OFL and ML may offer more clinically favorable outcomes, especially when the type of composite substrate is uncertain.\u003c/p\u003e\u003cp\u003eIn the DR groups, NHC exhibited significantly higher SBS than BFC in the OB group, suggesting that BFC may require additional adhesive or resin application following bur treatment. This is consistent with Bonstein et al.[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e], who reported that diamond bur roughening improves bond strength in aged composite repair, and with Atalay et al. [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], who found that bur roughening alone is insufficient for optimal bonding in bulk-fill composites. Our findings align with the results reported by Valente et al.[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], which demonstrated that combining diamond bur roughening, phosphoric acid etching, and adhesive application significantly improves long-term repair bond strength in aged composites. The strong interfacial bond achieved with this protocol may be explained by the macro-retentive features created by diamond bur roughening, improved surface wettability, and potential chemical interaction between the substrate and repair resin facilitated by the adhesive agent[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn both composite types, significant differences in SBS were observed among DR groups depending on the surface treatment applied. Particularly, NST and A groups consistently exhibited the lowest SBS values, while SEBond-containing groups, OFL, and ML provided superior outcomes. These findings indicate that surface treatment selection plays a critical role in optimizing repair performance for aged composite substrates. The null hypothesis stating that \u0026ldquo;surface treatments do not affect the SBS between layers of aged composite resins after diamond bur roughening\u0026rdquo; was rejected.\u003c/p\u003e\u003cp\u003eComposite resins are subject to hydrolytic degradation over time due to water diffusion, leading to matrix\u0026ndash;filler interface weakening, increased porosity, and surface changes that can impair repair bond strength[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. To simulate intraoral aging, specimens in this study were stored in distilled water for 15 days, a duration shown to reduce free radical activity and reactive methacrylate availability on the surface[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. As the chemical reactivity of the substrate decreases over time, achieving reliable copolymerization with new resin becomes more difficult. Consequently, surface treatments are necessary to re-establish macro-, micro-, or chemical bonding between aged and fresh composites[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. In line with previous findings, DR groups in both composite types showed lower bond strength values than IR groups. The null hypothesis stating that \u0026ldquo;There is no difference in the effect of surface treatments on SBS between freshly polymerized and aged composite resins.\u0026rdquo; was rejected.\u003c/p\u003e\u003cp\u003eNHCs are widely used in both anterior and posterior restorations due to their favorable mechanical properties and esthetic advantages. Their nanofiller content may reduce the degree of conversion by increasing light scattering, potentially enhancing chemical bonding during IR by leaving more unreacted monomers available at the surface[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. This could explain the superior performance of NHC compared to BFC in DR groups treated only with bur. BFCs, designed primarily for posterior use, allow for 4\u0026ndash;5 mm increments, improving clinical efficiency. Their modified formulation promotes deeper polymerization and reduces polymerization shrinkage stress[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. However, the high degree of conversion and more efficient photoinitiator systems in BFCs may have led to the significantly lower bond strength values observed in the OB group, where no additional resin was applied, and also in the SEPB group. This is likely due to the reduced availability of reactive methacrylate groups[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. The null hypothesis stating that \u0026ldquo;there is no difference in the effect of surface treatments on SBS between bulk-fill and nanohybrid composite resins\u0026rdquo; was partially rejected.\u003c/p\u003e\u003cp\u003eConsistent with previous studies[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], our results demonstrated that acid etching did not improve repair bond strength in DR and, in some cases, led to clinically unacceptable values. This observation aligns with reports indicating that acid treatment has minimal or no effect on bond strength[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. In the NHC DR group, acid application following bur roughening resulted in a substantial reduction in bond strength. In both IR and DR of NHC, phosphoric acid application prior to SEBond without primer did not improve SBS and was even associated with a slight, though statistically insignificant, reduction. These findings support previous studies reporting that phosphoric acid provides no added benefit when used before self-etch adhesives, likely due to its limited etching capability or potential to damage the composite surface[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe effectiveness of intermediate resin layers in composite repair is attributed to chemical bonding with the filler or matrix components and micromechanical retention achieved through monomer infiltration into surface irregularities. Proper adhesive application enhances surface wettability and facilitates chemical interaction between aged and newly applied composites[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAlthough universal adhesives containing functional monomers such as 10-MDP and silane offer simplified application and are widely used in clinical practice [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e], they did not demonstrate superior bond strength compared to other adhesive systems in this study. SingleBond Universal, which includes pre-hydrolyzed silane, showed higher\u0026mdash;but not statistically significant\u0026mdash;SBS than Prime\u0026amp;Bond in DR of NHC. These results are consistent with previous studies suggesting that silane-containing universal adhesives do not significantly improve composite repair bonding[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eIn NHC IR groups, the highest SBS was achieved with the use of a primer prior to SEBond application. Consistent with our findings, Cavalcanti et al.[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e] reported that two-step self-etch adhesives produced bond strengths comparable to the control in IR. However, in NHC DR and BFC IR, the use of a primer before bonding did not provide additional benefit, suggesting that an extra priming step may be unnecessary and time-consuming in these situations. Similarly, Rathke et al.[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e] recommended limiting primer application in clinical repairs to cases involving dentin exposure.\u003c/p\u003e\u003cp\u003eModeling liquids, also known as wetting or modeling agents, are used to reduce surface tension and improve the handling of composite resins by preventing the material from sticking to shaping instruments during placement[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. In this study, GC Modeling Liquid, used as a repair material, demonstrated high SBS in both IR and DR-particularly in BFC- and performed similarly to the control in NHC IR. Its favorable performance may be attributed to the absence of hydrophilic acidic monomers, reducing the risk of interfacial degradation between composite layers.\u003c/p\u003e\u003cp\u003eThe use of a hydrophobic, unfilled resin during composite layering has been reported to improve mechanical properties by reducing voids and interfacial defects between layers[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. In contrast, the use of hydrophilic lubricants has been associated with inferior mechanical performance and more pronounced discoloration[\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. This may be attributed to the high monomer content and increased fluid absorption, potentially altering the superficial composition of the composite. In the present study, layering with GC Modeling Liquid after cut-back yielded favorable results, supporting its clinical applicability in restorative procedures. Notably, ML achieved the highest SBS values in both IR and DR conditions of BFCs, further supporting its effectiveness as a repair material.\u003c/p\u003e\u003cp\u003eIn both composite types and repair periods, the highest incidence of adhesive failure was observed in A and NST groups, which also showed the lowest SBS values. In contrast, cohesive failures were predominantly seen in groups where adhesive resins, particularly ML and SEBond (with or without primer), were applied, often corresponding to higher SBS. However, no direct correlation between failure mode and SBS was established, and the predominance of cohesive failures may have limited the interpretability of shear bond test results.\u003c/p\u003e\u003cp\u003eNone of the surface treatment groups achieved the SBS values observed in the control group, where the oxygen-inhibited layer (OIL) was preserved. IR resulted in significantly higher SBS than DR for both composite types. The application of bonding agents after bur roughening improved SBS, particularly in DR, while unbonded DR groups yielded clinically unacceptable values. Modeling Liquid and hydrophobic resins were among the most effective agents, and additional acid or primer application before their use proved unnecessary. Silane-containing universal adhesives did not outperform hydrophobic resins. Notably, in the DR condition, diamond bur roughening alone resulted in higher bond strength in NHC compared to BFC. This in vitro study is limited by the use of only two composite types and short-term water aging. Further investigations involving a wider range of materials, long-term aging, and clinical contamination scenarios are recommended to validate and extend these findings.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eSBS: Shear Bond Strength\u003c/p\u003e\n\u003cp\u003eIR: Immediate Repair\u003c/p\u003e\n\u003cp\u003eDR: Delayed Repair\u003c/p\u003e\n\u003cp\u003eNHC: Nanohybrid Composite\u003c/p\u003e\n\u003cp\u003eBFC: Bulk-Fill Composite\u003c/p\u003e\n\u003cp\u003eST: Surface Treatment\u003c/p\u003e\n\u003cp\u003eNST: No Surface Treatment\u003c/p\u003e\n\u003cp\u003eSBU: Single Bond Universal\u003c/p\u003e\n\u003cp\u003ePBU: Prime\u0026amp;Bond Universal\u003c/p\u003e\n\u003cp\u003eSEPB: Clearfil SE Bond (Two-step protocol)\u003c/p\u003e\n\u003cp\u003eASEB: Clearfil SE Bond (Acid etch + bond only)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSEB: Clearfil SE Bond (Bond only, no primer)\u003c/p\u003e\n\u003cp\u003eOFL: OptiBond FL\u003c/p\u003e\n\u003cp\u003eML: GC Modeling Liquid\u003c/p\u003e\n\u003cp\u003ePMMA: Polymethyl Methacrylate\u003c/p\u003e\n\u003cp\u003eOB: Only Bur (surface roughening with no adhesive)\u003c/p\u003e\n\u003cp\u003eOIL: Oxygen-Inhibited Layer\u003c/p\u003e\n\u003cp\u003eMDP-10: Methacryloyloxydecyl Dihydrogen Phosphate\u003c/p\u003e\n\u003cp\u003eLED: Light-Emitting Diode\u003c/p\u003e\n\u003cp\u003ePVC: Polyvinyl Chloride\u003c/p\u003e\n\u003cp\u003eSPSS: Statistical Package for the Social Sciences\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Non-Interventional Clinical Research Ethics Committee of the Faculty of Dentistry, Sel\u0026ccedil;uk University (Approval No: 2022/55, Date: December 9, 2022). Written consent to participate was not applicable as this was an in vitro study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was supported by the Scientific Research Projects Coordination Unit of Sel\u0026ccedil;uk University (Project No: 23132005).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMCE contributed to the conception and design of the study, data acquisition, analysis, interpretation, and manuscript writing. NC contributed to the supervision, critical revision of the manuscript, and approval of the final version. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMCE is an Assistant Professor in the Department of Restorative Dentistry at Bursa Uludağ University, T\u0026uuml;rkiye. His academic work focuses on adhesive dentistry and composite repair protocols. This study aligns with his clinical and research interest in optimizing immediate and delayed repair techniques using different surface treatments and composite systems.\u003c/p\u003e\n\u003cp\u003eNC is a Professor in the Department of Restorative Dentistry at Sel\u0026ccedil;uk University. Her research includes esthetic composite restorations, adhesive protocols, and surface conditioning techniques. She has extensive experience in supervising restorative dental material studies.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data and materials used in the study can be obtained by contacting thecorresponding author.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial number\u003c/strong\u003e: not applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eHan I-H, Kang D-W, Chung C-H, Choe H-C, Son M-K. Effect of various intraoral repair systems on the shear bond strength of composite resin to zirconia. The journal of advanced prosthodontics. 2013;5(3):248-55.\u003c/li\u003e\n\u003cli\u003eBijelic-Donova J, Garoushi S, Lassila LV, Vallittu PK. Oxygen inhibition layer of composite resins: effects of layer thickness and surface layer treatment on the interlayer bond strength. Eur J Oral Sci. 2015;123(1):53-60.\u003c/li\u003e\n\u003cli\u003eHadi S, Tjandrawinata R, Fibryanto E. The effect of oxygen-inhibited layer and its inhibition technique on diametral tensile strength values of various nanofilled composite resin types. Journal of International Oral Health. 2024;16(2):150-7.\u003c/li\u003e\n\u003cli\u003eVelazquez E, Vaidyanathan J, Vaidyanathan TK, Houpt M, Shey Z, Von Hagen S. Effect of primer solvent and curing mode on dentin shear bond strength and interface morphology. Quintessence international. 2003;34(7).\u003c/li\u003e\n\u003cli\u003eGhivari S, Chandak M, Manvar N. Role of oxygen inhibited layer on shear bond strength of composites. J Conserv Dent. 2010;13(1):39-41.\u003c/li\u003e\n\u003cli\u003e\u0026Ouml;zcan M, Pekkan G. Effect of different adhesion strategies on bond strength of resin composite to composite-dentin complex. Operative dentistry. 2013;38(1):63-72.\u003c/li\u003e\n\u003cli\u003eSwift Jr E, LeValley B, Boyer D. Evaluation of new methods for composite repair. Dental Materials. 1992;8(6):362-5.\u003c/li\u003e\n\u003cli\u003eTabatabaei , Alizade Y, Taalim S. Effect of various surface treatment on repair strength of composite resin. 2004.\u003c/li\u003e\n\u003cli\u003eMitsaki-Matsou H, Karanika-Kouma A, Papadoyiannis Y, Theodoridou-Pahine S. An in vitro study of the tensile strength of composite resins repaired with the same or another composite resin. Quintessence international. 1991;22(6).\u003c/li\u003e\n\u003cli\u003eDe Munck J, Van Landuyt K, Peumans M, Poitevin A, Lambrechts P, Braem M, et al. A critical review of the durability of adhesion to tooth tissue: methods and results. J Dent Res. 2005;84(2):118-32.\u003c/li\u003e\n\u003cli\u003eScherrer SS, Cesar PF, Swain MV. Direct comparison of the bond strength results of the different test methods: a critical literature review. Dental Materials. 2010;26(2):e78-e93.\u003c/li\u003e\n\u003cli\u003eFrankenberger R, Kramer N, Sindel J. Repair strength of etched vs silica-coated metal-ceramic and all-ceramic restorations. Oper Dent. 2000;25(3):209-15.\u003c/li\u003e\n\u003cli\u003eTeixeira EC, Bayne SC, Thompson JY, Ritter AV, Swift EJ. Shear bond strength of self-etching bonding systems in combination with various composites used for repairing aged composites. Journal of Adhesive Dentistry. 2005;7(2).\u003c/li\u003e\n\u003cli\u003eRinastiti M, \u0026Ouml;zcan M, Siswomihardjo W, Busscher HJ. Immediate repair bond strengths of microhybrid, nanohybrid and nanofilled composites after different surface treatments. Journal of dentistry. 2010;38(1):29-38.\u003c/li\u003e\n\u003cli\u003eda Costa TRF, Serrano AM, Atman APF, Loguercio AD, Reis A. Durability of composite repair using different surface treatments. Journal of Dentistry. 2012;40(6):513-21.\u003c/li\u003e\n\u003cli\u003eLucena-Mart\u0026iacute;n C, Gonz\u0026aacute;lez-L\u0026oacute;pez S, de Mondelo JMN-R. The effect of various surface treatments and bonding agents on the repaired strength of heat-treated composites. The Journal of prosthetic dentistry. 2001;86(5):481-8.\u003c/li\u003e\n\u003cli\u003eEl-Deeb HA, Ghalab RM, Akah MME, Mobarak EH. Repair bond strength of dual-cured resin composite core buildup materials. Journal of advanced research. 2016;7(2):263-9.\u003c/li\u003e\n\u003cli\u003eKholief EA, Mahmoud ESM, El Chabrawy SM. Shear bond strength for immediate and delayed repair of composite with microhybrid and nanohybrid resins using different bonding agents. Alexandria Dental Journal. 2020;45(2):104-10.\u003c/li\u003e\n\u003cli\u003eAtalay C, Yazici AR, Ozgunaltay G. Bond strengths of bulk-fill resin composite repairs: effect of different surface treatment protocols in vitro. Journal of Adhesion Science and Technology. 2018;32(9):921-30.\u003c/li\u003e\n\u003cli\u003eBonstein T, Garlapo D, John Jr D, Bush PJ. Evaluation of varied repair protocols applied to aged composite resin. Journal of Adhesive Dentistry. 2005;7(1).\u003c/li\u003e\n\u003cli\u003eValente LL, Sarkis-Onofre R, Goncalves AP, Fernandez E, Loomans B, Moraes RR. Repair bond strength of dental composites: systematic review and meta-analysis. International Journal of Adhesion and Adhesives. 2016;69:15-26.\u003c/li\u003e\n\u003cli\u003eFawzy AS, El-Askary FS, Amer MA. Effect of surface treatments on the tensile bond strength of repaired water-aged anterior restorative micro-fine hybrid resin composite. Journal of dentistry. 2008;36(12):969-76.\u003c/li\u003e\n\u003cli\u003eSouza MOd, Leitune VCB, Rodrigues SB, Samuel SMW, Collares FM. One-year aging effects on microtensile bond strengths of composite and repairs with different surface treatments. Brazilian oral research. 2017;31:e4.\u003c/li\u003e\n\u003cli\u003eGarcia D, Yaman P, Dennison J, Neiva G. Polymerization shrinkage and depth of cure of bulk fill flowable composite resins. Operative dentistry. 2014;39(4):441-8.\u003c/li\u003e\n\u003cli\u003eLoomans BA, Cardoso MV, Roeters F, Opdam N, De Munck J, Huysmans M, et al. Is there one optimal repair technique for all composites? Dental Materials. 2011;27(7):701-9.\u003c/li\u003e\n\u003cli\u003eBayne SC. Dental biomaterials: where are we and where are we going? Journal of dental education. 2005;69(5):571-85.\u003c/li\u003e\n\u003cli\u003eTarle Z, Attin T, Marovic D, Andermatt L, Ristic M, Taub\u0026ouml;ck T. Influence of irradiation time on subsurface degree of conversion and microhardness of high-viscosity bulk-fill resin composites. Clinical oral investigations. 2015;19:831-40.\u003c/li\u003e\n\u003cli\u003eOgunyinka A, Palin W, Shortall A, Marquis P. Photoinitiation chemistry affects light transmission and degree of conversion of curing experimental dental resin composites. Dental Materials. 2007;23(7):807-13.\u003c/li\u003e\n\u003cli\u003eOzcan M, Barbosa SH, Melo RM, Galhano GA, Bottino MA. Effect of surface conditioning methods on the microtensile bond strength of resin composite to composite after aging conditions. Dent Mater. 2007;23(10):1276-82.\u003c/li\u003e\n\u003cli\u003eAkg\u0026uuml;l S, Kedici Alp C, Bala O. Repair potential of a bulk‐fill resin composite: Effect of different surface‐treatment protocols. European Journal of Oral Sciences. 2021;129(6):e12814.\u003c/li\u003e\n\u003cli\u003eBrum RT, Vieira S, Freire A, Mazur RF, De Souza EM, Rached RN. Effect of organic solvents compared to sandblasting on the repair bond strength of nanohybrid and nanofilled composite resins. Indian Journal of Dental Research. 2017;28(4):433.\u003c/li\u003e\n\u003cli\u003eAlex G. Universal adhesives: the next evolution in adhesive dentistry. Compend Contin Educ Dent. 2015;36(1):15-26.\u003c/li\u003e\n\u003cli\u003eSilva CLd, Scherer MM, Mendes LT, Casagrande L, Leitune VCB, Lenzi TL. Does use of silane-containing universal adhesive eliminate the need for silane application in direct composite repair? Brazilian Oral Research. 2020;34.\u003c/li\u003e\n\u003cli\u003eStape THS, Tulkki O, Salim IA, Jamal KN, Mutluay MM, Tezvergil-Mutluay A. Composite repair: On the fatigue strength of universal adhesives. dental materials. 2022;38(2):231-41.\u003c/li\u003e\n\u003cli\u003eCavalcanti AN, De Lima AF, Peris AR, Mitsui FHO, Marchi GM. Effect of surface treatments and bonding agents on the bond strength of repaired composites. Journal of Esthetic and Restorative Dentistry. 2007;19(2):90-8.\u003c/li\u003e\n\u003cli\u003eRathke A, Tymina Y, Haller B. Effect of different surface treatments on the composite\u0026ndash;composite repair bond strength. Clinical Oral Investigations. 2009;13(3):317-23.\u003c/li\u003e\n\u003cli\u003eKutuk ZB, Erden E, Aksahin DL, Durak ZE, Dulda AC. Influence of modeling agents on the surface properties of an esthetic nano-hybrid composite. Restorative Dentistry \u0026amp; Endodontics. 2020;45(2).\u003c/li\u003e\n\u003cli\u003eMuenchow EA, Sedrez-Porto JA, Piva E, Pereira-Cenci T, Cenci MS. Use of dental adhesives as modeler liquid of resin composites. Dental Materials. 2016;32(4):570-7.\u003c/li\u003e\n\u003cli\u003ePaolone G, Mazzitelli C, Josic U, Scotti N, Gherlone E, Cantatore G, et al. Modeling Liquids and Resin-Based Dental Composite Materials\u0026mdash;A Scoping Review. Materials. 2022;15(11):3759.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Adhesives, Adhesive Systems, Bond Strength, Composite Resins, Dental Bonding, Dental Restoration Repair, Immediate Dental Restoration, Shear Strength","lastPublishedDoi":"10.21203/rs.3.rs-7482603/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7482603/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground:\u003c/strong\u003eComposite resin restorations frequently require repair due to fractures, marginal defects, or esthetic failures. The effectiveness of composite repair depends heavily on the surface treatment applied prior to bonding. This study aimed to evaluate the effects of various surface treatment protocols on the shear bond strength(SBS) between composite resin layers in same-visit immediate repair and delayed repair conditions, using bulk-fill and nanohybrid composite resins.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e Two types of composite resin materials—NeoSpectra ST HV (nanohybrid) and Tetric N-Ceram Bulk-Fill—were tested. A total of ten surface treatment protocols were evaluated under both immediate and delayed repair conditions (n = 10 per subgroup). Following grinding with a diamond bur, the surfaces were treated with one of the following: phosphoric acid, universal adhesives (Single Bond Universal, Prime\u0026amp;Bond Universal), three application modes of Clearfil SE Bond (two-step, bond only without primer, or phosphoric acid application followed by bond only), Optibond FL without primer, or GC Modeling Liquid. Additionally, direct layering without any surface treatment was included as a control. SBS was measured using a universal testing machine, and failure modes were analyzed using a stereomicroscope. One-way analysis of variance and Tukey’s post hoc test were used for statistical analysis (p = 0.05).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e Immediate repair groups showed significantly higher SBS than DR groups across both composite types. The highest SBS were observed with GC Modeling Liquid and hydrophobic bonding agents, particularly in the bulk-fill immediate repair groups. Phosphoric acid application alone, or in combination with self-etch adhesive, did not improve bond strength. Universal adhesives did not outperform hydrophobic agents in any condition. Direct layering without treatment resulted in the lowest bond strength, especially in delayed repair.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003e\u003cbr\u003e\nSurface treatment protocol significantly affects the success of composite resin repair. Hydrophobic adhesives and GC Modeling Liquid proved to be the most effective options, especially for same-visit immediate repairs. Simplified approaches avoiding unnecessary etching or priming may offer clinically efficient solutions without compromising bond strength.\u003c/p\u003e","manuscriptTitle":"Does Composite Repair Time Affect Repair Protocol, Immediate or Delayed?","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-16 14:51:51","doi":"10.21203/rs.3.rs-7482603/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-11-05T11:22:21+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-22T14:50:23+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-11T16:26:32+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-10T14:15:32+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"255922845643481735406122872719724647066","date":"2025-10-06T07:06:42+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"236620392578095526588293428523129969902","date":"2025-10-04T14:38:17+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"246627377912833778625876389488963944534","date":"2025-10-03T15:15:32+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-03T11:27:30+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-09-01T16:39:30+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-29T11:29:06+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-29T11:27:55+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Oral Health","date":"2025-08-28T17:42:57+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"fdfe840e-3a70-49b1-938d-9193b7286412","owner":[],"postedDate":"October 16th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-22T16:02:54+00:00","versionOfRecord":{"articleIdentity":"rs-7482603","link":"https://doi.org/10.1186/s12903-025-07509-7","journal":{"identity":"bmc-oral-health","isVorOnly":false,"title":"BMC Oral Health"},"publishedOn":"2025-12-15 15:57:21","publishedOnDateReadable":"December 15th, 2025"},"versionCreatedAt":"2025-10-16 14:51:51","video":"","vorDoi":"10.1186/s12903-025-07509-7","vorDoiUrl":"https://doi.org/10.1186/s12903-025-07509-7","workflowStages":[]},"version":"v1","identity":"rs-7482603","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7482603","identity":"rs-7482603","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}