Physico-mechanical properties of aesthetic resin composites

Physico-mechanical properties of aesthetic resin composites | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Physico-mechanical properties of aesthetic resin composites Fei Chen, Dongmei Wang, Hao Luo, Peng Yu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4299087/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Objectives To evaluate the physico-mechanical properties, including water sorption (WS) and solubility (SL), flexural strength (σ f ) and modulus of elasticity (E mod ), as well as Vickers hardness (VHN) value of most currently available aesthetic resin composites by comparing them with conventional resin composite. Materials and methods Universal-shde resin composite OMNICHROMA (OMNI; Tokuyama), Beautifil Unishade (BU; Shofu), Essentia (EN; GC), and A3 shade of aesthetic resin composites Harmonize (HM; Kerr), conventional resin composite Tetric N Cream (TNC; Ivoclar Vivadent) were evaluated in this study. Volume and weight were recorded every 24 h of water immersion of resin composites ( n = 5) for the calculation of WS and SL. Bar shaped specimens were sectioned from each material ( n = 5), E mod and σ f were evaluated using a three-point bending test. Bottom and top of the specimens ( n = 3) of VHN were obtained for three spots using Vickers micro-hardness tester. Afterwards, bottom-top hardness ratio was calculated. One-way ANOVA, Tukey’s test, Kruskal-Wallis, Pearson’s correlation test, and Paired-samples t-test were computed ( p < 0.05). Results HM showed significant the highest WS and SL ( p 0.05). BU showed significant the highest E mod ( p < 0.05). HM recorded the highest VHN value ( p < 0.05), and significantly the lowest bottom-top hardness ratio ( p < 0.05). Conclusions The aesthetic resin composites showed comparable physico-mechanical properties compared to conventional resin composite TNC. Clinical relevance The physico-mechanical properties of resin composite material influence the long-term clinical performance of the restoration. Aesthetic resin composite Physico-mechanical properties Water sorption and solubility Elastic modulus and flexural strength Surface hardness Figures Figure 1 Figure 2 Introduction Dental resin composites were introduced commercially to clinical in mid 1960s after the application of etchants, and their introduction was one of the most significant contributions to dentistry in the last century [ 1 ]. Resin composites are the most versatility demanded restorations for anterior and posterior teeth in dental practice due to their improved physical and mechanical properties as well as their satisfied aesthetic appeal through the developments in filler technology [ 2 , 3 ]. Since people’s more concern for aesthetics, the research effort has focused on improving the matching the color of the resin composite to the surrounding cavity to increase their clinical service [ 4 ]. Composite technology rapidly evolves with new aesthetic characteristic of resin composites products being released in the market every year. Aesthetic resin composites with improved translucency and enhanced structural integrity provided better blending capabilities, which blended into the teeth even if the shade picked was a little off [ 5 , 6 ]. Shortly after the application of aesthetic resin composites, universal-shade resin composites are born on demand marketably, universal-shade is only single shade, which is expected to match nearly all shades of the surrounding tooth [ 4 , 7 ]. Some researches have reported that universal-shade type of resin composites revealed barely indistinguishable color difference compared to the conventional types of resin composites [ 7 , 8 ]. The optical properties such as reflectance and opalescence characteristic of universal-shade resin composites vary among materials [ 8 ]. An increasing number of studies further revealed the color stability and clinical wide use of universal-shade resin composites [ 4 , 9 ]. To attain longevity and reliability in clinical application, the physical and mechanical properties of the restorative material is equally important for academics and for clinicians to understand the restorative materials they used [ 10 ]. Due to the fast updating of newly advent aesthetic resin composites, there are not much information available on their physical and mechanical properties. Water sorption and solubility are important factors for resin-based composites, which correlates with the convention and longevity of the restorations [ 11 ]. When the resin composite is exposed to aqueous environment, it might suffer hydrolysis with consequent leaching of unreacted monomers or even low molecular weight oligomers [ 11 , 12 ]. Also, the water uptake of resin-based composites might result in chemical degradation, causing a hydrolytic breakdown of the filler-matrix interface, with a consequent decrease of its mechanical properties such as hardness, flexural strength and elastic modulus [ 12 , 13 ]. Ultimately, all these factors together cause material`s degradation, with significant decrease of mechanical properties, ultimately lead to restoration failure [ 11 , 13 – 15 ]. Physical and mechanical characteristics of restorative materials are important concerns when determining suitable restorative materials because they strongly influence the clinical longevity of restorations [ 14 , 16 ]. Therefore, the aim of this study would be the evaluation of physical and mechanical properties of different aesthetic dental composites available in the market. The null hypotheses were the investigated universal-shade resin composites and aesthetic resin composites would not present any differences in mechanical properties which includes water sorption (WS), solubility (SL), flexural strength (σ f ) and elastic modulus (E mod ), as well as Vickers hardness (VHN) characteristic compared with conventional resin composite. Materials and methods Resin composites selected in this study Commercial universal-shade resin composites, OMNICHROMA (OMNI; Tokuyama Dental, Tokyo, Japan), Beautifil Unishade (BU; Shofu, Kyoto, Japan), and Essentia (EN; GC, Tokyo, Japan); an aesthetic resin composites Harmonize (A3; HM; Kerr, Orange, CA, USA), and a widely clinical used conventional resin composite Tetric-N-Cream (A3; TNC; Ivoclar Vivadent, Schaan, Liechtenstein) were used in this study. Materials name & manufacturers, abbreviation, and their composition are presented in Table 1 . Water Sorption and Solubility Water sorption (WS) and solubility (SL) were performed according to ISO 4049:2009 (Dentistry — Polymer-based filling, restorative and luting materials, International Organization for Standardization). Twenty-five disk-shaped specimens with 15 mm in diameter and 1 mm in thickness ( n = 5) were prepared from above five composites. Resins were photo-polymerized using a LED light-curing unit (Bluephase G2, Ivoclar Vivadent, Liechtenstein) with the irradiation of 1000 ± 50 mW/cm 2 for 20 s. Afterwards, specimens were stored in a light-proof container at 37 ℃ for 1 h. The excess material was removed from the surface of the mold using a 1000 grit silicon carbide paper. The volume (V in cm 3 ) of each specimen was calculated according to their dimensions measured by a digital caliper (Mitutoyo Sul Americana Ltda., Suzano, SP, Brazil). Specimens were placed in a desiccator at 37 ℃ and weighed every 24 h using an analytical balance (JK-180, Chiyo Balance Corp., Tokyo, Japan) with an accuracy of 0.1 mg until a constant mass (m 1 ) was reached. Specimens were individually stored in deionized water for 7 days dividing by their group. Following water immersion, the disk-shaped specimens were washed with deionized water, blot-dried with absorbent paper, and weighed again (m 2 ). Then, specimens were placed in a desiccator, and their mass was recorded every 24 h until it was constant (m 3 ), as described before. WS and SL were calculated (in µg/mm 3 ) using the following equations: $$\text{W}\text{S}=\frac{{\text{m}}_{2}-{\text{m}}_{3}}{\text{V}}$$ $$\text{S}\text{L}=\frac{{\text{m}}_{1}-{\text{m}}_{3}}{\text{V}}$$ Where “m 1 ” is the constant mass of the specimens (in µg) prior to immersion in water; “m 2 ” is the mass (in µg) after immersion in water for 24 h or 7 days; “m 3 ” is the constant mass of the specimens (in µg) after being reconditioned in the desiccator; and “V” is the volume of each specimen (in mm 3 ). Three-point bending test Twenty-five bar-shaped composite specimens (25 × 2 × 2 mm, n = 5) were made for the three-point bending test in order to measure their flexural strength (σ f ) and elastic modulus (E mod ). Resin composites were placed into polytetrafluoroethylene molds and covered with Mylar strips and glass slides from both sides, top and bottom. All specimens were light-cured following the same procedures described above for the water sorption and solubility tests. However, due to the length of the specimens, light-curing was performed in three non-overlapping irradiation cycles, since the tip of the light-curing unit was about 10 mm wide. Cured specimens were lightly polished using SiC paper grit 1000 and stored in incubated in distilled water at 37 ℃。σ f and E mod were determined using a universal testing machine (LRX Plus, Lloyd Instrument) equipped with a three-point bending jig. The specimens were loaded on a 20 mm support-span (knife edge geometry) at a 0.5 mm/s cross-head speed. E mod (GPa) and σ f (MPa) were calculated using the following equations: $${E}_{mod}=\frac{{L}^{3}\times \delta }{4\times w\times {t}^{3}\times 1000}$$ $${\sigma }\text{f}（\text{M}\text{P}\text{a}）=\frac{3\times {\text{F}}_{\text{m}\text{a}\text{x}}\times \text{L}}{2\times \text{w}\times {\text{t}}^{2}}$$ With L, and w the distance between supports, w and t the width and thickness of the bars (mm). δ is the slope of a force/deformation curve in the elastic region (N/mm). F max (N) is the load recorded in the elastic portion. Vicker's hardness Vicker’s microhardness test was selected in this study since it is suitable for testing several types of materials especially brittle ones. For the resin composites, a stainless steel mold (ϕ10.0 × 2.0 mm) was used to shape the specimens. The mold was filled with tested resin composite paste ( n = 3) and a Mylar strip was applied. Light curing was conducted with an irradiance of 2000 mW/cm 2 (Pencure 2000; Morita, Kyoto, Japan). The surfaces of the samples were then polished applying a constant force with 1500, 2000, 2500, and 3000 grit waterproof silicon carbide papers (Matador; Starcke GmbH & Co. KG, Melle, Germany) on a low-speed handpiece. The VHN of the specimen was measured with an HMV-2T microhardness tester (Shimadzu, Tokyo, Japan). The specimen were employed the load of 0.98 N and a 10-s dwell time at a temperature of 20 ℃. VHN were obtained for three spots both bottom and top of each specimen. Indentations with greater than 0.5 mm distance between adjacent was maintained with the purpose of avoiding the influence of the residual stress. Afterwards, bottom-top hardness ratio was calculated. Statistical Analysis Data for WS, VHN were analyzed with one-way ANOVA and Tukey’s test. SL, σ f and E mod were not homocedastic, thus Kruskal-Wallis analysis was performed. Possible correlations between WS and SL were analyzed using Pearson’s correlation test. Paired-samples t-test were used to compare the results of upwards and backwards of VHN. The significance level was set at 95%. All statistical analyses were performed using a standard statistical software package (SPSS 26.0, Chicago, USA). Results Water sorption and solubility Figure 1 shows the amount of water sorption (WS), solubility (SL), and correlation of WS and SL of the five specimens. Significant differences were observed regarding the WS and SL of materials ( p < 0.001). HM showed significantly the highest WS as well as SL (27.2 ± 1.1µg/mm 3 for WS; 3.4 ± 0.3µg/mm 3 for SL) compared with others tested resin composites. There was no significant difference of WS and SL between OMNI, BU, EN, and TNB ( p > 0.05). Peason’s correlation tests showed a statistically significant positive correlation between WS and SL ( r = 0.846, p < 0.05). Flexural strength and elastic modulus Figure 2 shows the flexural strength (σ f ) and elastic modulus (E mod ) of the five specimens. There were no significantly difference of σ f of the tested materials ( p > 0.05). σ f varied between 55.3 GPa for BU and 71.9 GPa for OMNI. While there was significant difference in E mod regarding the materials ( p < 0.05). BU showed significantly the highest E mod (9.0 GPa) compared with other tested resin composites ( p 0.05). Vicker's hardness One-way ANOVA revealed statistically significant differences regarding the Vickers hardness (VHN) value of the materials ( p < 0.01). HM recorded significantly the highest VHN both top and bottom side (53.1 ± 2.9 HV for top; 46.4 ± 1.2 HV for bottom, p 0.05). EN recorded the lowest VHN. HM showed significantly the lowest bottom-top hardness ratio (Bottom-top ratio = 0.87, p < 0.05). Discussion In this study, we assessed the WS, SL σ f , E mod and VHN of three newly marketing universal-shade resin composites (OMNI, BU, and EN), an aesthetic resin composite (A3 shade of HM) and a conventional resin composite (A3 shade of TNC). With regard to the properties of the restoratives, the results were generally dependent on the material evaluated, the universal-shade of resin composites OMNI and BU resulted comparable WS, SL σ f , E mod and VHN compared with conventional resin composite, EN resulted in significantly the lowest VHN, while aesthetic resin composite HM resulted in significantly the highest WS and SL. Therefore, the null hypothesis that the investigated aesthetic resin composites would not present any differences in physical-mechanical properties compared with conventional resin composite was partially rejected. Solvent sorption was investigated as a tool to determine a material’s hydrophobicity [ 17 ]. During dissolution process, water uptake and swelling of resin composite, followed by the disintegration of the polymeric matrix into solutions, as well as unreacted monomers released in the oral cavity, leading to the consequence of solubility [ 17 – 19 ]. Therefore, solvent sorption and solubility are directly correlated to the extent of hydrolyic effects, bounded to the stability of the organic fraction of the resin composites, altering mechanical properties [ 17 ]. More specifically, resin composite with more hydrophilic monomers resulting in greater water absorption and eventually accelerate the hydrolytic degradation process, and more hydrophobic monomers resulting in less water sorption and enhanced mechanical properties [ 11 , 12 , 17 ]. The evaluation in current study of water sorption (WS) and water solubility (SL) have been made in accordance with the ISO 4049 standard. WS and water SL values of resin composites should not exceed 40 ug/mm 3 and 7.5 ug/mm 3 respectively according to ISO 4049 [ 17 , 21 ]. All the tested resin composites materials in this study met these criteria. Tested resin composites presented statistically similar values, expect for HM, which presented significantly the highest WS and SL compared with other materials ( p < 0.05). The results also indicated strong correlation between WS and SL, higher water sorption demonstrate high solubility. Several factors may have influenced WS and SL such as the polymer matrix hydrophilicity; cross-linking density; solvents used and the porosity of fillers [ 13 , 22 ]. The most important element of composite resins is the organic matrix section. The presence of hydrophilic resin matrices like Bis-GMA, TEGDMA, and urethane dimethacrylate (UDMA) may cause absorption of water to a greater degree than hydrophobic resin. Ferracane et al. evaluated the WS ability of different monomers, and showed that the differences in water sorption of polymer network depending on monomer type (TEGDMA > Bis-GMA > UDMA > Bis-EMA) [ 23 ]. Similar results were showed that TEGDMA absorbs the highest amount of water and releases the lowest amount of unreacted monomer. UDMA and Bis-EMA absorb less water and release higher unreacted monomer [ 24 ]. The present study comfirmed with these results, UDMA-free HM exhibited significantly the highest WS and SL compared with other tested resin composites ( p < 0.05). Hydrophilic character of the resin matrix of HM, which includes a large amount of Bis-GMA and TEGDMA, caused the greater absorption of water, ultimately negatively affect the mechanical properties. On the other hands, at similar organic contents of tested resin composites (OMNI, BU, TNC, and EN), small differences in WS and SL were seen ( p > 0.05). In general terms, WS and SL also correlates with the type of the filler [ 13 ]. BU contained “pre-reacted glass ionomer (PRG)”-based fluoro-alumina-silicate glass, which is assuming to release and recharge fluoride by absorbing a certain amount of water [ 21 ]. Besides, giomer composites might have more surface vacancies via the release of fluoride ions [ 25 ]. As a results, PRG-contained resin composites of BU exhibited higher WS than OMNI, EN, and TNC, as well as higher SL than EN and TNC, though there was no significant difference between the groups. The modulus of elasticity and flexural strength are determined in a 3-point bending test from the deflection of the material in relationship to the applied force [ 26 , 27 ]. Elastic modulus represents the relative stiffness of a material within the elastic range, while flexural strength is the maximum stress of material needed to fracture a specimen subjected to flexural loading [ 28 ]. High flexural strength in combination with a tooth-like, high modulus of elasticity means low distortion [ 28 , 29 ]. The limit of σ f is 80 MPa for polymer-based restorative materials as suitable for restorations involving occlusal surfaces from ISO 4049/2009 recommendation [ 29 , 30 ]. In the present study, all of the tested restorations have been below the ideal value, no significant difference were found between the tested restoratives in regard with σ f ( p > 0.05). Some authors claimed that there are some factors that can play a relevent role in modifying the σ f such as stress transfer between filler particles and matrix, as well as adhesion between the components [ 31 , 32 ]. Previous studies have found that high-modulus composites behave well clinically, which contribute to a better stress distribution for the cavity [ 26 , 27 ]. Besides, high-modulus composites have been noted to reduce ditching or crevicing at the occlusal margins compared with low-modulus composites [ 33 ]. The range of human dentin E mod is between 13 GPa-19 GPa, with slight measurement conditions [ 34 , 35 ]. It is obvious that the E mod of tested resin composite restorations are below human dentin. BU showed the highest E mod compared with other tested resin composites, which implied its long-term maintenance of internal and marginal adaptation. It can be noted that significant increase in E mod of various composite materials, with the increase of filler content. The evidence from several studies [ 36 , 37 ], including the present study, exhibited that E mod is dominated by the amount of filler and increases exponentially with the volume fraction of filler. BU with high filler loading (87%) exhibited significantly the highest E mod . As a results, prevents microleakage, secondary decay as well as dislodgement. Additionally, with increasing network density, the flexibility of the polymer chains is reduced. The surface hardness of a dental material is a property to resist indentations [ 38 ]. A low surface hardness value of composite restoration is largely related to inadequate wear resistance and proclivity to scratching, which may negatively influence fatigue strength and finally lead to failure of the restoration. The bottom/top hardness ratio indicate the degree of polymerization, the lower of the ratio, the lower polymerization depth and the more incomplete of the conversion of the resin composites [ 39 ]. Additionally, the current review of the published literature has shown that a bottom/top ratio ≥ 0.8 was considered as clinically acceptable [ 40 ]. In the present study, HM showed significantly the highest VHN properties, whereas significantly the lowest hardness ratio (bottom/top ratio = 0.87, p < 0.05), which indicated its relatively weaker degree of polymerization, nevertheless, it is acceptable in clinical situations. It is known that the microhardness of polymer composites is considerably influenced by the fillers employed [ 41 ]. Surface hardness of resin composite largely depends on the concentration of the filler particle and particle size [ 42 ]. Lombardini et al have found that nano-composites tested were significantly higher than hybrid-filled resin composite [ 43 ]. Adversely, the microhardness of nano-filled resin composites was found to be inferior to that of a hybrid by some researchers, Cao and others reported significantly lower VHN of the nano-filled resin composites compared with all tested hybrid composites in their study [ 44 ]. Their findings aligned with ours. In the present study, nano-filled resin composite OMNI showed significantly lower VHN than hybrid-filled resin BU and HM ( p 0.05). Additionally, microhybrid filled composite EN showed significantly the lowest VHN, the filler of microhybrid contains contains micro size of filler from 850 nm to submicroscopic filler averaging of 17 nm. The superior VHN behavior of hybrid-filled resin may due to its less interparticle spacing, therefore compact protection of the softer resin matrix and less filler plucking, eventually prevent crack propagation and hence increase the material’s strength. However, even if the findings of the present studies are promising, further in vivo studies are still needed in order to confirm the results. Conclusion Considering the results obtained in the present study, the following conclusion can be drawn: Aesthetic resin composite HM showed significantly the highest water sorption and solubility compared with other tested materials, which implied its vulnerability to suffer hydrolysis. No significant difference was found between the tested restoratives in regard with flexural strength. BU exhibited significantly the highest modulus of elasticity . EN showed significantly the lowest Vickers hardness value. Surface hardness of resin composite largely depends on the concentration of the filler particle and particle size. Declarations Funding This study has received funding from Foundation of Beijing Tongren Hospital, Capital Medical University (No. 2021-YJJ-ZZL-061) and Youth Founding of Peking University School and Hospital of Stomatology (No. PKUSS20220109). Competing interests The authors declare no competing interests. References Ferracane JL (2011) Resin composite - state of the art. Dent Mater 27:29-38. Chen F, Toida Y, Islam R, Alam A, Chowdhury AFMA, Yamauti M, Sano H (2021) Evaluation of shade matching of a novel supra-nano filled esthetic resin composite employing structural color using simplified simulated clinical cavities. J Esthet Restor Dent 33:874-883. 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Chaves LVF, Oliveira SN, Özcan M, Acchar W, Caldas MRGR, Assunção IV, Souza ROAE, Borges BCD (2019) Interfacial Properties and Bottom/Top Hardness Ratio Produced by Bulk Fill Composites in Dentin Cavities. Braz Dent J 30:476-483. Pimentel ES, França FMG, Turssi CP, Basting RT, Vieira-Junior WF (2023) Effects of in vitro erosion on surface texture, microhardness, and color stability of resin composite with S-PRG fillers. Clin Oral Investig 27:3545-3556. Erdemir U, Yildiz E, Eren MM, Ozel S (2013) Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period. J Appl Oral Sci 21:124-131. Lombardini M, Chiesa M, Scribante A, Colombo M, Poggio C (2012) Influence of polymerization time and depth of cure of resin composites determined by Vickers hardness. Dent Res J (Isfahan) 9:735-740. Cao L, Zhao X, Gong X, Zhao S (2013) An in vitro investigation of wear resistance and hardness of composite resins. Int J Clin Exp Med 6:423-430. Tables Table 1. Resin composites used in this study. Material Abbreviation Manufacturer Lot Type of filler Filler content (wt%) Organic matrices OMNICHROMA OMNI Tokuyama Dental, Tokyo, Japan 019E89 Supranano filled (260 nm spherical SiO 2 -ZrO 2 filler) 79 UDMA, TEGDMA Beautifil Unishade BU Shofu, Kyoto, Japan 012151 Glass powder 87 Bis-GMA, Bis-MPEPP, UDMA, TEGDMA Essentia EN GC, Tokyo, Japan 2003091 Microhybrid (strontium glass, lanthanide fluoride, fumed silica, FAISi glass) 81 Bis-EMA, Bis-GMA Bis-MEPP, UDMA, TEGDMA Harmonize (A3) HM Kerr, Orange, CA, USA 6901692 Nanohybrid (Silica, Zirconia, Barium Glass) 81 Bis-GMA, Bis-EMA, TEGDMA Tetric-N-Cream TNC Ivoclar Vivadent, Schaan, Liechtenstein Y10641 Nanohybrid (Barium glass, YbF 3 (0.04-3 mm), mixed oxide and copolymers (40 nm and 3000 nm) 80-81 Bis-GMA, UDMA, UDMA, urethane dimethacrylate; TEGDMA, triethyleneglycol dimethacrylate; Bis-GMA, bisphenol A-glycidyl methacrylate; Bis-MEPP, Bis (p-methacryloxy (ethoxy)1-2 phenyl)-propane; Bis-EMA, Ethoxylated bisphenol-A-dimethacrylate. Table 2. Mean surface Vickers hardness of tested resin composites at upwards, downwards, and their difference value. Different lower-case letters show statistical differences of Vickers hardness between the materials. Different upper-case letters show a statistical difference between the sides. Group Top SD Bottom SD Bottom/Top ratio SD OMNI 39.5 A, a 2.0 35.7 B, ab 1.3 0.90 a 0.03 BU 48.0 A, b 1.9 38.4 B, a 3.0 0.80 a 0.07 EN 30.7 A, c 1.7 31.0 A, b 1.0 1.00 a 0.04 HM 53.1 A, d 2.9 46.4 B, c 1.2 0.87 b 0.04 TNC 40.8 A, a 0.8 37.5 A, a 2.8 0.92 a 0.08 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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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-4299087","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":295084473,"identity":"9f2c30a7-5a33-445a-b6b5-d807949fde25","order_by":0,"name":"Fei Chen","email":"","orcid":"","institution":"Department of Stomatology, Beijing Tongren Hospital, Beijing","correspondingAuthor":false,"prefix":"","firstName":"Fei","middleName":"","lastName":"Chen","suffix":""},{"id":295084474,"identity":"317959a3-161f-4de1-b5fc-f99ce194c536","order_by":1,"name":"Dongmei Wang","email":"","orcid":"","institution":"Second Dental Clinical Division, Peking University School and Hospital of Stomatology, Beijing","correspondingAuthor":false,"prefix":"","firstName":"Dongmei","middleName":"","lastName":"Wang","suffix":""},{"id":295084475,"identity":"ba85c2f3-ffca-45d1-9ec7-ee2d0c5a8455","order_by":2,"name":"Hao Luo","email":"","orcid":"","institution":"Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing","correspondingAuthor":false,"prefix":"","firstName":"Hao","middleName":"","lastName":"Luo","suffix":""},{"id":295084476,"identity":"2d1e418c-644a-4fa9-aae2-b1aebd99aa5f","order_by":3,"name":"Peng Yu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAz0lEQVRIiWNgGAWjYPACmwTGBhDNRryWNNK1HE6A0MRoMbiRe/Bxwa/zeczTzhgwfCg7zMA/u4GQlrxk45l9t4sZZ+cYMM44d5hB4s4BQlpyzKR5e24nNgK1MPO2HWYwkEggqMX8N2/POYiWv0RqMWPm+XEAooWRGC2SZ94lS/M2JAP9klZwsOdcOo/EDQJa+I7nHvzM88cuz3B28sYHP8qs5fhnENCicICHgYGxjYHBsIGB4QBQgAe/eiCQbwCp+QNkEFQ6CkbBKBgFIxYAALyzR7SWMXOsAAAAAElFTkSuQmCC","orcid":"","institution":"Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing","correspondingAuthor":true,"prefix":"","firstName":"Peng","middleName":"","lastName":"Yu","suffix":""}],"badges":[],"createdAt":"2024-04-21 02:09:18","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4299087/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4299087/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":55350059,"identity":"575cef9f-9c33-4d87-a670-8e9598c5672c","added_by":"auto","created_at":"2024-04-26 05:34:23","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":21570,"visible":true,"origin":"","legend":"\u003cp\u003eMean of water sorption (a), solubility (b), and the correlation (c) of each of the tested resin composites. Horizon bars indicate values that are statistically significant (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05).\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4299087/v1/e77949ebf8d97fd6d1e9036e.png"},{"id":55350402,"identity":"6281edc5-dd6c-4762-b2b5-4cf0d68eb439","added_by":"auto","created_at":"2024-04-26 05:42:23","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":14283,"visible":true,"origin":"","legend":"\u003cp\u003eMean of flexural strength (a) and elastic modulus (b) of each of the tested resin composites.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4299087/v1/9d71834577fb1b6fe286a865.png"},{"id":55953846,"identity":"64b29585-a0be-4d0d-b107-b2f0bbe5572f","added_by":"auto","created_at":"2024-05-06 19:17:23","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":505745,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4299087/v1/cb3636bc-4dad-40c0-87e1-7fc35c7eb3e0.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Physico-mechanical properties of aesthetic resin composites","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDental resin composites were introduced commercially to clinical in mid 1960s after the application of etchants, and their introduction was one of the most significant contributions to dentistry in the last century [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Resin composites are the most versatility demanded restorations for anterior and posterior teeth in dental practice due to their improved physical and mechanical properties as well as their satisfied aesthetic appeal through the developments in filler technology [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSince people\u0026rsquo;s more concern for aesthetics, the research effort has focused on improving the matching the color of the resin composite to the surrounding cavity to increase their clinical service [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Composite technology rapidly evolves with new aesthetic characteristic of resin composites products being released in the market every year. Aesthetic resin composites with improved translucency and enhanced structural integrity provided better blending capabilities, which blended into the teeth even if the shade picked was a little off [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Shortly after the application of aesthetic resin composites, universal-shade resin composites are born on demand marketably, universal-shade is only single shade, which is expected to match nearly all shades of the surrounding tooth [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Some researches have reported that universal-shade type of resin composites revealed barely indistinguishable color difference compared to the conventional types of resin composites [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The optical properties such as reflectance and opalescence characteristic of universal-shade resin composites vary among materials [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. An increasing number of studies further revealed the color stability and clinical wide use of universal-shade resin composites [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTo attain longevity and reliability in clinical application, the physical and mechanical properties of the restorative material is equally important for academics and for clinicians to understand the restorative materials they used [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Due to the fast updating of newly advent aesthetic resin composites, there are not much information available on their physical and mechanical properties. Water sorption and solubility are important factors for resin-based composites, which correlates with the convention and longevity of the restorations [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. When the resin composite is exposed to aqueous environment, it might suffer hydrolysis with consequent leaching of unreacted monomers or even low molecular weight oligomers [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Also, the water uptake of resin-based composites might result in chemical degradation, causing a hydrolytic breakdown of the filler-matrix interface, with a consequent decrease of its mechanical properties such as hardness, flexural strength and elastic modulus [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Ultimately, all these factors together cause material`s degradation, with significant decrease of mechanical properties, ultimately lead to restoration failure [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePhysical and mechanical characteristics of restorative materials are important concerns when determining suitable restorative materials because they strongly influence the clinical longevity of restorations [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Therefore, the aim of this study would be the evaluation of physical and mechanical properties of different aesthetic dental composites available in the market. The null hypotheses were the investigated universal-shade resin composites and aesthetic resin composites would not present any differences in mechanical properties which includes water sorption (WS), solubility (SL), flexural strength (σ\u003csub\u003ef\u003c/sub\u003e) and elastic modulus (E\u003csub\u003emod\u003c/sub\u003e), as well as Vickers hardness (VHN) characteristic compared with conventional resin composite.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003eResin composites selected in this study\u003c/h2\u003e\n \u003cp\u003eCommercial universal-shade resin composites, OMNICHROMA (OMNI; Tokuyama Dental, Tokyo, Japan), Beautifil Unishade (BU; Shofu, Kyoto, Japan), and Essentia (EN; GC, Tokyo, Japan); an aesthetic resin composites Harmonize (A3; HM; Kerr, Orange, CA, USA), and a widely clinical used conventional resin composite Tetric-N-Cream (A3; TNC; Ivoclar Vivadent, Schaan, Liechtenstein) were used in this study. Materials name \u0026amp; manufacturers, abbreviation, and their composition are presented in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003eWater Sorption and Solubility\u003c/h2\u003e\n \u003cp\u003eWater sorption (WS) and solubility (SL) were performed according to ISO 4049:2009 (Dentistry \u0026mdash; Polymer-based filling, restorative and luting materials, International Organization for Standardization). Twenty-five disk-shaped specimens with 15 mm in diameter and 1 mm in thickness (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;5) were prepared from above five composites. Resins were photo-polymerized using a LED light-curing unit (Bluephase G2, Ivoclar Vivadent, Liechtenstein) with the irradiation of 1000\u0026thinsp;\u0026plusmn;\u0026thinsp;50 mW/cm\u003csup\u003e2\u003c/sup\u003e for 20 s. Afterwards, specimens were stored in a light-proof container at 37 ℃ for 1 h. The excess material was removed from the surface of the mold using a 1000 grit silicon carbide paper.\u003c/p\u003e\n \u003cp\u003eThe volume (V in cm\u003csup\u003e3\u003c/sup\u003e) of each specimen was calculated according to their dimensions measured by a digital caliper (Mitutoyo Sul Americana Ltda., Suzano, SP, Brazil). Specimens were placed in a desiccator at 37 ℃ and weighed every 24 h using an analytical balance (JK-180, Chiyo Balance Corp., Tokyo, Japan) with an accuracy of 0.1 mg until a constant mass (m\u003csub\u003e1\u003c/sub\u003e) was reached. Specimens were individually stored in deionized water for 7 days dividing by their group. Following water immersion, the disk-shaped specimens were washed with deionized water, blot-dried with absorbent paper, and weighed again (m\u003csub\u003e2\u003c/sub\u003e). Then, specimens were placed in a desiccator, and their mass was recorded every 24 h until it was constant (m\u003csub\u003e3\u003c/sub\u003e), as described before. WS and SL were calculated (in \u0026micro;g/mm\u003csup\u003e3\u003c/sup\u003e) using the following equations:\u003c/p\u003e\n \u003cdiv id=\"Equa\" class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e$$\\text{W}\\text{S}=\\frac{{\\text{m}}_{2}-{\\text{m}}_{3}}{\\text{V}}$$\u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Equb\" class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equb\" name=\"EquationSource\"\u003e$$\\text{S}\\text{L}=\\frac{{\\text{m}}_{1}-{\\text{m}}_{3}}{\\text{V}}$$\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eWhere \u0026ldquo;m\u003csub\u003e1\u003c/sub\u003e\u0026rdquo; is the constant mass of the specimens (in \u0026micro;g) prior to immersion in water; \u0026ldquo;m\u003csub\u003e2\u003c/sub\u003e\u0026rdquo; is the mass (in \u0026micro;g) after immersion in water for 24 h or 7 days; \u0026ldquo;m\u003csub\u003e3\u003c/sub\u003e\u0026rdquo; is the constant mass of the specimens (in \u0026micro;g) after being reconditioned in the desiccator; and \u0026ldquo;V\u0026rdquo; is the volume of each specimen (in mm\u003csup\u003e3\u003c/sup\u003e).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003eThree-point bending test\u003c/h2\u003e\n \u003cp\u003eTwenty-five bar-shaped composite specimens (25 \u0026times; 2 \u0026times; 2 mm, \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;5) were made for the three-point bending test in order to measure their flexural strength (\u0026sigma;\u003csub\u003ef\u003c/sub\u003e) and elastic modulus (E\u003csub\u003emod\u003c/sub\u003e). Resin composites were placed into polytetrafluoroethylene molds and covered with Mylar strips and glass slides from both sides, top and bottom. All specimens were light-cured following the same procedures described above for the water sorption and solubility tests. However, due to the length of the specimens, light-curing was performed in three non-overlapping irradiation cycles, since the tip of the light-curing unit was about 10 mm wide. Cured specimens were lightly polished using SiC paper grit 1000 and stored in incubated in distilled water at 37 ℃。\u0026sigma;\u003csub\u003ef\u003c/sub\u003e and E\u003csub\u003emod\u003c/sub\u003e were determined using a universal testing machine (LRX Plus, Lloyd Instrument) equipped with a three-point bending jig. The specimens were loaded on a 20 mm support-span (knife edge geometry) at a 0.5 mm/s cross-head speed. E\u003csub\u003emod\u003c/sub\u003e (GPa) and \u0026sigma;\u003csub\u003ef\u003c/sub\u003e (MPa) were calculated using the following equations:\u003c/p\u003e\n \u003cdiv id=\"Equc\" class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equc\" name=\"EquationSource\"\u003e$${E}_{mod}=\\frac{{L}^{3}\\times \\delta }{4\\times w\\times {t}^{3}\\times 1000}$$\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equd\" class=\"Equation\"\u003e\u003cdiv class=\"mathdisplay\" id=\"FileID_Equd\" name=\"EquationSource\"\u003e$${\\sigma }\\text{f}（\\text{M}\\text{P}\\text{a}）=\\frac{3\\times {\\text{F}}_{\\text{m}\\text{a}\\text{x}}\\times \\text{L}}{2\\times \\text{w}\\times {\\text{t}}^{2}}$$\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eWith L, and w the distance between supports, w and t the width and thickness of the bars (mm). \u0026delta; is the slope of a force/deformation curve in the elastic region (N/mm). F\u003csub\u003emax\u003c/sub\u003e (N) is the load recorded in the elastic portion.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n \u003ch2\u003eVicker\u0026apos;s hardness\u003c/h2\u003e\n \u003cp\u003eVicker\u0026rsquo;s microhardness test was selected in this study since it is suitable for testing several types of materials especially brittle ones. For the resin composites, a stainless steel mold (ϕ10.0 \u0026times; 2.0 mm) was used to shape the specimens. The mold was filled with tested resin composite paste (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;3) and a Mylar strip was applied. Light curing was conducted with an irradiance of 2000 mW/cm\u003csup\u003e2\u003c/sup\u003e (Pencure 2000; Morita, Kyoto, Japan). The surfaces of the samples were then polished applying a constant force with 1500, 2000, 2500, and 3000 grit waterproof silicon carbide papers (Matador; Starcke GmbH \u0026amp; Co. KG, Melle, Germany) on a low-speed handpiece. The VHN of the specimen was measured with an HMV-2T microhardness tester (Shimadzu, Tokyo, Japan). The specimen were employed the load of 0.98 N and a 10-s dwell time at a temperature of 20 ℃. VHN were obtained for three spots both bottom and top of each specimen. Indentations with greater than 0.5 mm distance between adjacent was maintained with the purpose of avoiding the influence of the residual stress. Afterwards, bottom-top hardness ratio was calculated.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003eStatistical Analysis\u003c/h2\u003e\n \u003cp\u003eData for WS, VHN were analyzed with one-way ANOVA and Tukey\u0026rsquo;s test. SL, \u0026sigma;\u003csub\u003ef\u003c/sub\u003e and E\u003csub\u003emod\u003c/sub\u003e were not homocedastic, thus Kruskal-Wallis analysis was performed. Possible correlations between WS and SL were analyzed using Pearson\u0026rsquo;s correlation test. Paired-samples t-test were used to compare the results of upwards and backwards of VHN. The significance level was set at 95%. All statistical analyses were performed using a standard statistical software package (SPSS 26.0, Chicago, USA).\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eWater sorption and solubility\u003c/h2\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the amount of water sorption (WS), solubility (SL), and correlation of WS and SL of the five specimens. Significant differences were observed regarding the WS and SL of materials (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). HM showed significantly the highest WS as well as SL (27.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u0026micro;g/mm\u003csup\u003e3\u003c/sup\u003e for WS; 3.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u0026micro;g/mm\u003csup\u003e3\u003c/sup\u003e for SL) compared with others tested resin composites. There was no significant difference of WS and SL between OMNI, BU, EN, and TNB (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Peason\u0026rsquo;s correlation tests showed a statistically significant positive correlation between WS and SL (\u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.846, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eFlexural strength and elastic modulus\u003c/h2\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the flexural strength (σ\u003csub\u003ef\u003c/sub\u003e) and elastic modulus (E\u003csub\u003emod\u003c/sub\u003e) of the five specimens. There were no significantly difference of σ\u003csub\u003ef\u003c/sub\u003e of the tested materials (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). σ\u003csub\u003ef\u003c/sub\u003e varied between 55.3 GPa for BU and 71.9 GPa for OMNI. While there was significant difference in E\u003csub\u003emod\u003c/sub\u003e regarding the materials (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). BU showed significantly the highest E\u003csub\u003emod\u003c/sub\u003e (9.0 GPa) compared with other tested resin composites (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), while there were no significant differences of E\u003csub\u003emod\u003c/sub\u003e for OMNI, EN, HM, and TNC (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eVicker's hardness\u003c/h2\u003e \u003cp\u003eOne-way ANOVA revealed statistically significant differences regarding the Vickers hardness (VHN) value of the materials (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). HM recorded significantly the highest VHN both top and bottom side (53.1\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9 HV for top; 46.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2 HV for bottom, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), followed with BU (48.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9 HV for top; 38.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0 HV for bottom). There was no significant difference between OMNI and TNB (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). EN recorded the lowest VHN. HM showed significantly the lowest bottom-top hardness ratio (Bottom-top ratio\u0026thinsp;=\u0026thinsp;0.87, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, we assessed the WS, SL σ\u003csub\u003ef\u003c/sub\u003e, E\u003csub\u003emod\u003c/sub\u003e and VHN of three newly marketing universal-shade resin composites (OMNI, BU, and EN), an aesthetic resin composite (A3 shade of HM) and a conventional resin composite (A3 shade of TNC). With regard to the properties of the restoratives, the results were generally dependent on the material evaluated, the universal-shade of resin composites OMNI and BU resulted comparable WS, SL σ\u003csub\u003ef\u003c/sub\u003e, E\u003csub\u003emod\u003c/sub\u003e and VHN compared with conventional resin composite, EN resulted in significantly the lowest VHN, while aesthetic resin composite HM resulted in significantly the highest WS and SL. Therefore, the null hypothesis that the investigated aesthetic resin composites would not present any differences in physical-mechanical properties compared with conventional resin composite was partially rejected.\u003c/p\u003e \u003cp\u003eSolvent sorption was investigated as a tool to determine a material\u0026rsquo;s hydrophobicity [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. During dissolution process, water uptake and swelling of resin composite, followed by the disintegration of the polymeric matrix into solutions, as well as unreacted monomers released in the oral cavity, leading to the consequence of solubility [\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Therefore, solvent sorption and solubility are directly correlated to the extent of hydrolyic effects, bounded to the stability of the organic fraction of the resin composites, altering mechanical properties [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. More specifically, resin composite with more hydrophilic monomers resulting in greater water absorption and eventually accelerate the hydrolytic degradation process, and more hydrophobic monomers resulting in less water sorption and enhanced mechanical properties [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe evaluation in current study of water sorption (WS) and water solubility (SL) have been made in accordance with the ISO 4049 standard. WS and water SL values of resin composites should not exceed 40 ug/mm\u003csup\u003e3\u003c/sup\u003e and 7.5 ug/mm\u003csup\u003e3\u003c/sup\u003e respectively according to ISO 4049 [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. All the tested resin composites materials in this study met these criteria. Tested resin composites presented statistically similar values, expect for HM, which presented significantly the highest WS and SL compared with other materials (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). The results also indicated strong correlation between WS and SL, higher water sorption demonstrate high solubility.\u003c/p\u003e \u003cp\u003eSeveral factors may have influenced WS and SL such as the polymer matrix hydrophilicity; cross-linking density; solvents used and the porosity of fillers [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The most important element of composite resins is the organic matrix section. The presence of hydrophilic resin matrices like Bis-GMA, TEGDMA, and urethane dimethacrylate (UDMA) may cause absorption of water to a greater degree than hydrophobic resin. Ferracane et al. evaluated the WS ability of different monomers, and showed that the differences in water sorption of polymer network depending on monomer type (TEGDMA\u0026thinsp;\u0026gt;\u0026thinsp;Bis-GMA\u0026thinsp;\u0026gt;\u0026thinsp;UDMA\u0026thinsp;\u0026gt;\u0026thinsp;Bis-EMA) [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Similar results were showed that TEGDMA absorbs the highest amount of water and releases the lowest amount of unreacted monomer. UDMA and Bis-EMA absorb less water and release higher unreacted monomer [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. The present study comfirmed with these results, UDMA-free HM exhibited significantly the highest WS and SL compared with other tested resin composites (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Hydrophilic character of the resin matrix of HM, which includes a large amount of Bis-GMA and TEGDMA, caused the greater absorption of water, ultimately negatively affect the mechanical properties.\u003c/p\u003e \u003cp\u003eOn the other hands, at similar organic contents of tested resin composites (OMNI, BU, TNC, and EN), small differences in WS and SL were seen (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). In general terms, WS and SL also correlates with the type of the filler [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. BU contained \u0026ldquo;pre-reacted glass ionomer (PRG)\u0026rdquo;-based fluoro-alumina-silicate glass, which is assuming to release and recharge fluoride by absorbing a certain amount of water [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Besides, giomer composites might have more surface vacancies via the release of fluoride ions [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. As a results, PRG-contained resin composites of BU exhibited higher WS than OMNI, EN, and TNC, as well as higher SL than EN and TNC, though there was no significant difference between the groups.\u003c/p\u003e \u003cp\u003eThe modulus of elasticity and flexural strength are determined in a 3-point bending test from the deflection of the material in relationship to the applied force [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. Elastic modulus represents the relative stiffness of a material within the elastic range, while flexural strength is the maximum stress of material needed to fracture a specimen subjected to flexural loading [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. High flexural strength in combination with a tooth-like, high modulus of elasticity means low distortion [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe limit of σ\u003csub\u003ef\u003c/sub\u003e is 80 MPa for polymer-based restorative materials as suitable for restorations involving occlusal surfaces from ISO 4049/2009 recommendation [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. In the present study, all of the tested restorations have been below the ideal value, no significant difference were found between the tested restoratives in regard with σ\u003csub\u003ef\u003c/sub\u003e (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Some authors claimed that there are some factors that can play a relevent role in modifying the σ\u003csub\u003ef\u003c/sub\u003e such as stress transfer between filler particles and matrix, as well as adhesion between the components [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePrevious studies have found that high-modulus composites behave well clinically, which contribute to a better stress distribution for the cavity [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. Besides, high-modulus composites have been noted to reduce ditching or crevicing at the occlusal margins compared with low-modulus composites [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. The range of human dentin E\u003csub\u003emod\u003c/sub\u003e is between 13 GPa-19 GPa, with slight measurement conditions [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. It is obvious that the E\u003csub\u003emod\u003c/sub\u003e of tested resin composite restorations are below human dentin. BU showed the highest E\u003csub\u003emod\u003c/sub\u003e compared with other tested resin composites, which implied its long-term maintenance of internal and marginal adaptation. It can be noted that significant increase in E\u003csub\u003emod\u003c/sub\u003e of various composite materials, with the increase of filler content. The evidence from several studies [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e], including the present study, exhibited that E\u003csub\u003emod\u003c/sub\u003e is dominated by the amount of filler and increases exponentially with the volume fraction of filler. BU with high filler loading (87%) exhibited significantly the highest E\u003csub\u003emod\u003c/sub\u003e. As a results, prevents microleakage, secondary decay as well as dislodgement. Additionally, with increasing network density, the flexibility of the polymer chains is reduced.\u003c/p\u003e \u003cp\u003eThe surface hardness of a dental material is a property to resist indentations [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. A low surface hardness value of composite restoration is largely related to inadequate wear resistance and proclivity to scratching, which may negatively influence fatigue strength and finally lead to failure of the restoration. The bottom/top hardness ratio indicate the degree of polymerization, the lower of the ratio, the lower polymerization depth and the more incomplete of the conversion of the resin composites [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. Additionally, the current review of the published literature has shown that a bottom/top ratio\u0026thinsp;\u0026ge;\u0026thinsp;0.8 was considered as clinically acceptable [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. In the present study, HM showed significantly the highest VHN properties, whereas significantly the lowest hardness ratio (bottom/top ratio\u0026thinsp;=\u0026thinsp;0.87, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), which indicated its relatively weaker degree of polymerization, nevertheless, it is acceptable in clinical situations.\u003c/p\u003e \u003cp\u003eIt is known that the microhardness of polymer composites is considerably influenced by the fillers employed [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. Surface hardness of resin composite largely depends on the concentration of the filler particle and particle size [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]. Lombardini et al have found that nano-composites tested were significantly higher than hybrid-filled resin composite [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e]. Adversely, the microhardness of nano-filled resin composites was found to be inferior to that of a hybrid by some researchers, Cao and others reported significantly lower VHN of the nano-filled resin composites compared with all tested hybrid composites in their study [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]. Their findings aligned with ours. In the present study, nano-filled resin composite OMNI showed significantly lower VHN than hybrid-filled resin BU and HM (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), similarly VHN compared with hybrid-filled resin TNC (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Additionally, microhybrid filled composite EN showed significantly the lowest VHN, the filler of microhybrid contains contains micro size of filler from 850 nm to submicroscopic filler averaging of 17 nm. The superior VHN behavior of hybrid-filled resin may due to its less interparticle spacing, therefore compact protection of the softer resin matrix and less filler plucking, eventually prevent crack propagation and hence increase the material\u0026rsquo;s strength. However, even if the findings of the present studies are promising, further in vivo studies are still needed in order to confirm the results.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eConsidering the results obtained in the present study, the following conclusion can be drawn:\u003c/p\u003e\n\u003col\u003e\n \u003cli\u003eAesthetic resin composite HM showed significantly the highest water sorption and solubility compared with other tested materials, which\u0026nbsp;implied its vulnerability to suffer hydrolysis.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eNo significant difference was found between the tested restoratives in regard with\u0026nbsp;flexural strength. BU exhibited significantly the highest modulus of elasticity\u003csub\u003e.\u0026nbsp;\u003c/sub\u003e\u003c/li\u003e\n \u003cli\u003eEN showed significantly the lowest Vickers hardness value. Surface hardness of resin composite largely depends on the concentration of the filler particle and particle size.\u0026nbsp;\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e This study has received funding from Foundation of Beijing Tongren Hospital, Capital Medical University (No. 2021-YJJ-ZZL-061) and Youth Founding of Peking University School and Hospital of Stomatology (No. PKUSS20220109).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e The authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eFerracane JL (2011) Resin composite - state of the art. 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Dent Mater 29:835\u0026ndash;841.\u003c/li\u003e\n \u003cli\u003eGoracci C, Cadenaro M, Fontanive L, Giangrosso G, Juloski J, Vichi A, Ferrari M (2014) Polymerization efficiency and flexural strength of low-stress restorative composites. Dent Mater 30:688\u0026ndash;694.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eAsmussen E, Peutzfeldt A (2008) Class I and Class II restorations of resin composite: an FE analysis of the influence of modulus of elasticity on stresses generated by occlusal loading. Dent Mater 24:600-605.\u003c/li\u003e\n \u003cli\u003eWatts DC (1994) Elastic moduli and visco-elastic relaxation. J Dent 22:154-158.\u003c/li\u003e\n \u003cli\u003eXu HHK, Smith DT, Jahanmir S, Romberg E, Kelly JR, Thompson VP, Rekow ED (1998) Indentation damage and mechanical properties of human enamel and dentin. J Dent Res 77:472-480.\u003c/li\u003e\n \u003cli\u003eRandolph LD, Palin WM, Leloup G, Leprince JG\u0026nbsp;(2016)\u0026nbsp;Filler characteristics of modern dental resin composites and their influence on physico-mechanical properties. Dent Mater 32:1586-1599.\u003c/li\u003e\n \u003cli\u003eYamamoto T, Hanabusa M, Kimura S, Momoi Y, Hayakawa T\u0026nbsp;(2018)\u0026nbsp;Changes in polymerization stress and elastic modulus of bulk-fill resin composites for 24 hours after irradiation. Dent Mater J\u0026nbsp;37:87\u0026ndash;94.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eKarimzadeh A, R Koloor SS, Ayatollahi MR, Bushroa AR, Yahya MY\u0026nbsp;(2019)\u0026nbsp;Assessment of Nano-Indentation Method in Mechanical Characterization of Heterogeneous Nanocomposite Materials Using Experimental and Computational Approaches. Sci Rep 9:15763.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eLima RBW, Troconis CCM, Moreno MBP, Murillo-G\u0026oacute;mez F, De Goes MF\u0026nbsp;(2018)\u0026nbsp;Depth of cure of bulk fill resin composites: A systematic review. J Esthet Restor Dent\u0026nbsp;30:492-501.\u003c/li\u003e\n \u003cli\u003eChaves LVF, Oliveira SN, \u0026Ouml;zcan M, Acchar W, Caldas MRGR, Assun\u0026ccedil;\u0026atilde;o IV, Souza ROAE, Borges BCD\u0026nbsp;(2019)\u0026nbsp;Interfacial Properties and Bottom/Top Hardness Ratio Produced by Bulk Fill Composites in Dentin Cavities. Braz Dent J\u0026nbsp;30:476-483.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003ePimentel ES, Fran\u0026ccedil;a FMG, Turssi CP, Basting RT, Vieira-Junior WF (2023) Effects of in vitro erosion on surface texture, microhardness, and color stability of resin composite with S-PRG fillers. Clin Oral Investig 27:3545-3556.\u003c/li\u003e\n \u003cli\u003eErdemir U, Yildiz E, Eren MM, Ozel S\u0026nbsp;(2013)\u0026nbsp;Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period. J Appl Oral Sci\u0026nbsp;21:124-131.\u003c/li\u003e\n \u003cli\u003eLombardini M, Chiesa M, Scribante A, Colombo M, Poggio C (2012) Influence of polymerization time and depth of cure of resin composites determined by Vickers hardness. Dent Res J (Isfahan) 9:735-740.\u003c/li\u003e\n \u003cli\u003eCao L, Zhao X, Gong X, Zhao S (2013) An in vitro investigation of wear resistance and hardness of composite resins. Int J Clin Exp Med 6:423-430. \u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1. Resin composites used in this study.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"770\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.84375%\" valign=\"top\"\u003e\n \u003cp\u003eMaterial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.197916666666666%\" valign=\"top\"\u003e\n \u003cp\u003eAbbreviation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.364583333333334%\" valign=\"top\"\u003e\n \u003cp\u003eManufacturer\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.723958333333334%\" valign=\"top\"\u003e\n \u003cp\u003eLot\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.5625%\" valign=\"top\"\u003e\n \u003cp\u003eType of filler\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.630208333333334%\" valign=\"top\"\u003e\n \u003cp\u003eFiller content (wt%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.677083333333334%\" valign=\"top\"\u003e\n \u003cp\u003eOrganic matrices\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.84375%\" valign=\"top\"\u003e\n \u003cp\u003eOMNICHROMA\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.197916666666666%\" valign=\"top\"\u003e\n \u003cp\u003eOMNI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.364583333333334%\" valign=\"top\"\u003e\n \u003cp\u003eTokuyama Dental, Tokyo, Japan\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.723958333333334%\" valign=\"top\"\u003e\n \u003cp\u003e019E89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.5625%\" valign=\"top\"\u003e\n \u003cp\u003eSupranano filled (260 nm spherical SiO\u003csub\u003e2\u003c/sub\u003e-ZrO\u003csub\u003e2\u003c/sub\u003e filler)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.630208333333334%\" valign=\"top\"\u003e\n \u003cp\u003e79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.677083333333334%\" valign=\"top\"\u003e\n \u003cp\u003eUDMA, TEGDMA\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.84375%\" valign=\"top\"\u003e\n \u003cp\u003eBeautifil Unishade\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.197916666666666%\" valign=\"top\"\u003e\n \u003cp\u003eBU\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.364583333333334%\" valign=\"top\"\u003e\n \u003cp\u003eShofu, Kyoto, Japan\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.723958333333334%\" valign=\"top\"\u003e\n \u003cp\u003e012151\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.5625%\" valign=\"top\"\u003e\n \u003cp\u003eGlass powder \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.630208333333334%\" valign=\"top\"\u003e\n \u003cp\u003e87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.677083333333334%\" valign=\"top\"\u003e\n \u003cp\u003eBis-GMA, Bis-MPEPP, UDMA, TEGDMA\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.84375%\" valign=\"top\"\u003e\n \u003cp\u003eEssentia\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.197916666666666%\" valign=\"top\"\u003e\n \u003cp\u003eEN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.364583333333334%\" valign=\"top\"\u003e\n \u003cp\u003eGC, Tokyo, Japan\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.723958333333334%\" valign=\"top\"\u003e\n \u003cp\u003e2003091\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.5625%\" valign=\"top\"\u003e\n \u003cp\u003eMicrohybrid (strontium glass, lanthanide fluoride, fumed silica, FAISi\u0026nbsp;glass)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.630208333333334%\" valign=\"top\"\u003e\n \u003cp\u003e81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.677083333333334%\" valign=\"top\"\u003e\n \u003cp\u003eBis-EMA, Bis-GMA Bis-MEPP,\u003c/p\u003e\n \u003cp\u003eUDMA, TEGDMA\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.84375%\" valign=\"top\"\u003e\n \u003cp\u003eHarmonize (A3)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.197916666666666%\" valign=\"top\"\u003e\n \u003cp\u003eHM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.364583333333334%\" valign=\"top\"\u003e\n \u003cp\u003eKerr, Orange, CA, USA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.723958333333334%\" valign=\"top\"\u003e\n \u003cp\u003e6901692\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.5625%\" valign=\"top\"\u003e\n \u003cp\u003eNanohybrid (Silica, Zirconia, Barium Glass)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.630208333333334%\" valign=\"top\"\u003e\n \u003cp\u003e81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.677083333333334%\" valign=\"top\"\u003e\n \u003cp\u003eBis-GMA, Bis-EMA, TEGDMA\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.84375%\" valign=\"top\"\u003e\n \u003cp\u003eTetric-N-Cream\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.197916666666666%\" valign=\"top\"\u003e\n \u003cp\u003eTNC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.364583333333334%\" valign=\"top\"\u003e\n \u003cp\u003eIvoclar Vivadent, Schaan, Liechtenstein\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.723958333333334%\" valign=\"top\"\u003e\n \u003cp\u003eY10641\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.5625%\" valign=\"top\"\u003e\n \u003cp\u003eNanohybrid\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(Barium glass, YbF\u003csub\u003e3\u003c/sub\u003e (0.04-3 mm), mixed oxide and copolymers (40\u0026nbsp;nm and 3000\u0026nbsp;nm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.630208333333334%\" valign=\"top\"\u003e\n \u003cp\u003e80-81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.677083333333334%\" valign=\"top\"\u003e\n \u003cp\u003eBis-GMA, UDMA,\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eUDMA, urethane dimethacrylate; TEGDMA, triethyleneglycol dimethacrylate; Bis-GMA, bisphenol A-glycidyl methacrylate; Bis-MEPP, Bis (p-methacryloxy (ethoxy)1-2 phenyl)-propane; Bis-EMA, Ethoxylated bisphenol-A-dimethacrylate.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Table 2. Mean surface Vickers hardness of tested resin composites at upwards, downwards, and their difference value. Different lower-case letters show statistical differences of Vickers hardness between the materials. Different upper-case letters show a statistical difference between the sides.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"530\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"12.075471698113208%\" valign=\"top\"\u003e\n \u003cp\u003eGroup\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.79245283018868%\" valign=\"top\"\u003e\n \u003cp\u003eTop\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.11320754716981%\" valign=\"top\"\u003e\n \u003cp\u003eSD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.9811320754717%\" valign=\"top\"\u003e\n \u003cp\u003eBottom\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.622641509433961%\" valign=\"top\"\u003e\n \u003cp\u003eSD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.9811320754717%\" valign=\"top\"\u003e\n \u003cp\u003eBottom/Top ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.433962264150944%\" valign=\"top\"\u003e\n \u003cp\u003eSD\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"12.075471698113208%\" valign=\"top\"\u003e\n \u003cp\u003eOMNI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.79245283018868%\" valign=\"top\"\u003e\n \u003cp\u003e39.5 A, a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.11320754716981%\" valign=\"top\"\u003e\n \u003cp\u003e2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.9811320754717%\" valign=\"top\"\u003e\n \u003cp\u003e35.7 B, ab\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.622641509433961%\" valign=\"top\"\u003e\n \u003cp\u003e1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.9811320754717%\" valign=\"top\"\u003e\n \u003cp\u003e0.90 a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.433962264150944%\" valign=\"top\"\u003e\n \u003cp\u003e0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"12.075471698113208%\" valign=\"top\"\u003e\n \u003cp\u003eBU\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.79245283018868%\" valign=\"top\"\u003e\n \u003cp\u003e48.0 A, b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.11320754716981%\" valign=\"top\"\u003e\n \u003cp\u003e1.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.9811320754717%\" valign=\"top\"\u003e\n \u003cp\u003e38.4 B, a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.622641509433961%\" valign=\"top\"\u003e\n \u003cp\u003e3.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.9811320754717%\" valign=\"top\"\u003e\n \u003cp\u003e0.80 a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.433962264150944%\" valign=\"top\"\u003e\n \u003cp\u003e0.07\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"12.075471698113208%\" valign=\"top\"\u003e\n \u003cp\u003eEN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.79245283018868%\" valign=\"top\"\u003e\n \u003cp\u003e30.7 A, c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.11320754716981%\" valign=\"top\"\u003e\n \u003cp\u003e1.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.9811320754717%\" valign=\"top\"\u003e\n \u003cp\u003e31.0 A, b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.622641509433961%\" valign=\"top\"\u003e\n \u003cp\u003e1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.9811320754717%\" valign=\"top\"\u003e\n \u003cp\u003e1.00 a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.433962264150944%\" valign=\"top\"\u003e\n \u003cp\u003e0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"12.075471698113208%\" valign=\"top\"\u003e\n \u003cp\u003eHM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.79245283018868%\" valign=\"top\"\u003e\n \u003cp\u003e53.1 A, d\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.11320754716981%\" valign=\"top\"\u003e\n \u003cp\u003e2.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.9811320754717%\" valign=\"top\"\u003e\n \u003cp\u003e46.4 B, c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.622641509433961%\" valign=\"top\"\u003e\n \u003cp\u003e1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.9811320754717%\" valign=\"top\"\u003e\n \u003cp\u003e0.87 b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.433962264150944%\" valign=\"top\"\u003e\n \u003cp\u003e0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"12.075471698113208%\" valign=\"top\"\u003e\n \u003cp\u003eTNC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.79245283018868%\" valign=\"top\"\u003e\n \u003cp\u003e40.8 A, a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.11320754716981%\" valign=\"top\"\u003e\n \u003cp\u003e0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.9811320754717%\" valign=\"top\"\u003e\n \u003cp\u003e37.5 A, a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.622641509433961%\" valign=\"top\"\u003e\n \u003cp\u003e2.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.9811320754717%\" valign=\"top\"\u003e\n \u003cp\u003e0.92 a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.433962264150944%\" valign=\"top\"\u003e\n \u003cp\u003e0.08\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Aesthetic resin composite, Physico-mechanical properties, Water sorption and solubility, Elastic modulus and flexural strength, Surface hardness","lastPublishedDoi":"10.21203/rs.3.rs-4299087/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4299087/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjectives\u003c/strong\u003e\u0026nbsp;To evaluate the physico-mechanical properties, including water sorption (WS) and solubility (SL), flexural strength (σ\u003csub\u003ef\u003c/sub\u003e) and modulus of elasticity (E\u003csub\u003emod\u003c/sub\u003e), as well as Vickers hardness (VHN) value of most currently available aesthetic resin composites by comparing them with conventional resin composite.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials and methods \u003c/strong\u003eUniversal-shde resin composite OMNICHROMA (OMNI; Tokuyama), Beautifil Unishade (BU; Shofu), Essentia (EN; GC), and A3 shade of aesthetic resin composites Harmonize (HM; Kerr), conventional resin composite Tetric N Cream (TNC; Ivoclar Vivadent) were evaluated in this study. Volume and weight were recorded every 24 h of water immersion of resin composites (\u003cem\u003en\u003c/em\u003e = 5) for the calculation of WS and SL. Bar shaped specimens were sectioned from each material (\u003cem\u003en\u003c/em\u003e = 5), E\u003csub\u003emod \u003c/sub\u003eand σ\u003csub\u003ef\u003c/sub\u003e were evaluated using a three-point bending test. Bottom and top of the specimens (\u003cem\u003en\u003c/em\u003e = 3) of VHN were obtained for three spots using Vickers micro-hardness tester. Afterwards, bottom-top hardness ratio was calculated. One-way ANOVA, Tukey’s test, Kruskal-Wallis, Pearson’s correlation test, and Paired-samples t-test were computed (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults \u003c/strong\u003eHM showed significant the highest WS and SL (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05). There was no significant difference in σ\u003csub\u003ef\u003c/sub\u003e regarding the materials (\u003cem\u003ep\u003c/em\u003e \u0026gt; 0.05). BU showed significant the highest E\u003csub\u003emod \u003c/sub\u003e(\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05). HM recorded the highest VHN value (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05), and significantly the lowest bottom-top hardness ratio (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u0026nbsp;\u0026nbsp;\u0026nbsp; \u003c/strong\u003eThe aesthetic resin composites showed comparable physico-mechanical properties compared to conventional resin composite TNC.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical relevance \u003c/strong\u003eThe physico-mechanical properties of resin composite material influence the long-term clinical performance of the restoration.\u003c/p\u003e","manuscriptTitle":"Physico-mechanical properties of aesthetic resin composites","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-26 05:34:18","doi":"10.21203/rs.3.rs-4299087/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"30dc32e8-e7de-4473-875b-47c2c30fba1f","owner":[],"postedDate":"April 26th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-05-06T19:09:12+00:00","versionOfRecord":[],"versionCreatedAt":"2024-04-26 05:34:18","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4299087","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4299087","identity":"rs-4299087","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}