Surface Roughness Of Composites Research Articles

Insights Into the Effects and Implications of Acidic Beverages on Resin Composite Materials in Dental Restorations: An InVitro Study.

Dental composite resins are commonly used due to their excellent physical and mechanical properties. However, exposure to beverages like Coca-Cola, Apple juice, and Black coffee can negatively impact these materials. This study examined the effects of these drinks on the surface microhardness and surface roughness of Nanohybrid, Giomer, and Dual-Cure Bulk-fill resin composites. Seventy-two disc-shaped resin composite specimens were prepared and divided into four groups (n = 18) based on immersion liquid: Group 1 (Coca-Cola), Group 2 (Apple juice), Group 3 (Black coffee), and Group 4 (Distilled water). The composites were further categorized into NeoSpectra (Subgroup 1), Beautifil II (Subgroup 2), and Predicta (Subgroup 3). Specimens were immersed for 14 days, alternating 18 h in beverages and 6 h in distilled water daily. Microhardness was measured using a Vickers microhardness tester, and surface roughness was analyzed by atomic force microscopy. Data were assessed using one-way ANOVA and Tukey's post hoc test, with significance set at p < 0.05. All groups experienced significant decrease in microhardness and surface roughness. Coca-Cola led to the highest roughness and hardness reduction. Among composites, the Nanohybrid resin (NeoSpectra) showed the least alteration. NeoSpectra ST, a nanohybrid composite, demonstrated superior resistance to acidic beverages compared to Giomer and Bulk-fill composites. The study finds that out of three composite materials, nanohybrid composites are the most acid resistant which provides a suitable material for patients who consume acidic beverages more frequently. In this way, clinicians can use this information to help optimally increase the longevity of their restorations by selecting materials according to oral exposure levels of acids in their patients.

Surface Roughness and Color Stability of Newly Developed Resin Composites With Color Adjustment Potential After Immersion in Staining Solutions.

The aim of this this study was to evaluate the surface roughness and color stability of resin composites (RCs) with color adjustment potential (CAP): Omnichroma (OM), (Tokuyama Dental, Tokyo, Japan); Neo Spectra ST (NS) (Dentsply Sirona, York, PA,USA); and Charisma Diamond One (CD) (Kulzer, Hanau, Germany), compared to a conventional RC, Filtek Z350XT (FZ) (3M ESPE, St. Paul, MN,USA), after immersion in three staining solutions, cola, coffee, and black tea, with distilled water as a control. Forty specimens (8 mm diameter x 2 mm thickness) were prepared for each RC material and divided into subgroups (n=10/group) based on the immersion solution. Surface roughness was measured at baseline and after 21 days of immersion using a non-contact optical profilometer. Color change (ΔE00) was evaluated at baseline, 1, 7, and 21 days with a spectrophotometer. The results showed that FZ demonstrated the lowest surface roughness (0.14), significantly differing from that of the other RCs with CAP (p<0.05), while no significant differences in surface roughness were observed between RCs with CAP (p>0.05). There were no significant changes in surface roughness before and after immersion in various solutions. The results for color change (ΔE00) were statistically significant. Neo Spectra ST showed the lowest tendency for color change, while Filtek Z350XT displayed a moderate potential, and Omnichroma and Charisma Diamond One showed the highest potential for color change.

Analysis of Mechanical Properties and Printing Orientation Influence of Composite Resin for 3D Printing Compared to Conventional Resin.

This study aimed to compare the flexural strength, surface roughness, and microhardness of a resin for three-dimensional (3D) printing and a conventional composite resin and to evaluate whether the printing orientation influences these properties. To evaluate the flexural resistance, test specimens were produced and divided into four groups: three groups of resins for 3D printing with inclinations of 0°, 45°, and 90° and one group of conventional composite resin. Forty discs were produced and subjected to a sandpaper-polishing sequence, and the surface roughness was measured using a roughness meter. The Vickers microhardness (HV) test was performed at three different points, and the average was obtained. The results were subjected to ANOVA statistical analysis and Tukey's test. There were statistical differences in the flexural strength and microhardness between the conventional resin and the resin used for 3D printing. No statistical difference in surface roughness was observed. The resin for 3D printing exhibited lower flexural strength and microhardness than conventional composite resins. We concluded that the resin for 3D printing had lower flexural strength and HV than the conventional composite resin but similar surface roughness. The printing orientation did not affect the flexural strength, whereas the hardness increased as the printing angle increased.

Effect of different polishing systems on surface roughness and gloss values of single-shade resin composites

BackgroundThe aim of this study was to evaluate variations in the surface roughness and gloss of different single-shade resin composites after polishing with a range of systems.MethodsIn total, 120 specimens were prepared from three different types of single-shade resin composites (supra-nanospherical—Omnichroma, nanohybrid—Charisma Diamond One, and microhybrid— Essentia Universal). The specimens were placed in distilled water and stored at 37 °C for 24 h. Each resin composite (n = 40) was divided into four groups (n = 10) according to the finishing/polishing (F/P) system: Mylar strip (control), Sof-Lex (multi-step), Twist Dia (two-step), and OneGloss (one-step). Surface roughness and gloss were measured. Surface characteristics were evaluated by atomic force microscopy (AFM) and a scanning electron microscope (SEM). A two-way analysis of variance (ANOVA) and Tukey’s honestly significant difference test were used for statistical analysis (p < 0.05).ResultsAmong all the composites, both the highest surface roughness and lowest gloss values were obtained in the groups treated with the OneGloss polishing system (p < 0.05). Compared with all the composites, Omnichroma had the lowest surface roughness and highest gloss values (except Twist Dia) both unpolished and after polishing with all the F/P systems (p < 0.05). All composites treated with the Twist Dia F/P system had similar gloss values. The results of the AFM and SEM analyses were consistent with the surface roughness measurements.ConclusionsThe gloss values of both the microhybrid and nanohybrid composites after F/P using the two-step system was superior to that of the traditional multistep system. The surface of the supra-nanofilled resin-based composite was smoother than that of both the microhybrid and nanohybrid composites.

Surface roughness and color change of methacrylate and ormocer-based direct composite versus indirect CAD/CAM composite blocks

ObjectivesTo assess the color stability and surface roughness of resin-free and resin-based nanohybrid composites after immersion in various staining media. MethodsA resin-free ormocer composite, Admira fusion (Voco, Germany), and a methacrylate resin composite, Grandio (Voco, Germany), were used for direct composite restorations with 30 discs per material formed using a Split Teflon mold (10 mm × 2 mm). Grandio Bloc (Voco, Germany) universal indirect CAD/CAM block specimens (n = 30) were sliced to a thickness of 2 mm with a precision saw. Each material was divided into 3 groups (n = 10 each) based on the immersion solution. Specimens were soaked in coffee (Turkish coffee, Baja, Saudi Arabia), cola (Coca-Cola Co., USA), and artificialsaliva. Color was evaluated before staining and after 30 days of staining using a spectrophotometer. Color change (ΔE*) was measured using the system of CIE L*a*b*. Surface roughness was determined using a stylus profilometer and represented using Atomic Force Microscopy before and after immersion in the staining solutions. ResultsAfter immersion in the staining solutions for 30 days, the color values of all the composites changed. Group A (coffee) had the greatest effect (ΔE > 5), and indirect Grandio blocs caused the greatest color change. The surface roughness values increased, particularly in group B (Coca-Cola), for all the tested materials after 30 days. Direct Grandio had a significantly higher roughness than the other materials (p < 0.001). ConclusionImmersion in coffee resulted in considerable color change, while immersion in cola had the greatest negative impact on surface roughness in all tested restorative materials. The nanohybrid ormocer did not provide better surface integrity than conventional methacrylate-based nanohybrid composites.

Can wheel polishers improve surface properties and color stability of monochromatic resin composites?

BackgroundTo overcome the color layering procedure, monochromatic resin composites have been introduced. However, little is known about their polishability, gloss and color stability. This study aimed to investigate the surface roughness, gloss, and color change of monochromatic resin composites polished with wheel systems after being immersed in coffee.Materials and methodsOmnichroma, Zenchroma, Essentia Universal, Charisma Diamond One and NeoSpectra ST were used to obtain 120-disc samples of 8 × 2 mm. Only one side of the sample was polished with Twist Dia (TWD) or Nova Twist (NOV). The samples were examined for surface roughness, gloss, and color (ΔE and ΔE00) before and after 7 days of immersion in coffee and subsequent repolishing. The discs were examined via SEM. Surface roughness and gloss values were analyzed using ANOVA, Tukey and Pearson correlation tests. ΔE and ΔE00 values were evaluated using T tests, multivariate ANOVA, and Dunnett’s post-hoc tests.ResultsFor TWD groups, the smoothest material was Omnichroma (p < 0.05), while for NOV groups, it was Omnichroma and Zenchroma. Omnichroma was the glossiest, while Charisma Diamond One was the least glossy. In TWD groups, Charisma Diamond One and Essentia Universal were the most discolored, while Zenchroma and Omnichroma were the least. For NOV groups, Essentia Universal and Charisma Diamond One were the most discolored, while NeoSpectra ST, Omnichroma and Zenchroma were the least. After repolishing, Charisma Diamond One did not reach the level of ΔE < 2, while the other groups showed values below. Color evaluation with the CIELab and CIEDE2000 systems revealed similar results for the TWD groups after post-staining.ConclusionsSmooth and glossy surfaces could be achieved with the wheel system regardless of the composite resin. Repolishing after discoloration ensures that the color recovery is below the acceptable limit. Color evaluations with CIELab and CIEDE2000 yielded similar results.

Effect of Different Polishing Methods on Composite Surface Roughness

Effect of Different Polishing Methods on Composite Surface Roughness

Indirect Composite Color Stability And Surface Roughness After Finishing

Indirect Composite Color Stability And Surface Roughness After Finishing

Bacterial adhesion and surface roughness of particulate-filled and short fiber-reinforced composites.

The objective of the study was to assess the initial adhesion of Streptococcus mutans (S. mutans) and surface roughness of different particulate-filled (PFC) and short fiber-reinforced (SFRC) composites. Five PFC composites (CeramX Universal, Filtek Universal, Omnichroma, Tetric Prime and Venus Diamond) and four SFRC composites (everX Posterior, everX Flow Bulk, everX Flow Dentin and experimental packable SFRC) were tested in this study. A non-contact 3D profilometer was employed to assess the surface roughness (Ra) of the polished specimens (using 4000-grit abrasive paper). For the bacterial adhesion test, the specimens (n = 5/group) were immersed in a solution of S. mutans to facilitate initial adhesion. To determine the number of cells on the surfaces of the discs as colony-forming units (CFU), the vials holding the microbial samples were highly agitated using a vortex machine. Subsequently, the samples were diluted multiple times and anaerobically incubated for 48h at 37°C on Mitis Salivarius Agar plates (Difco) supplemented with bacitracin. Bacterial adherence assessment was performed using SEM. The data were analyzed using ANOVA. All tested PFC and SFRC composites showed similar adhesion of S. mutan. The lowest Ra values (0.26µm) (p < 0.05) were found in the flowable SFRCs (everX Flow Bulk & Dentin), while the highest values (p < 0.05) were observed in CeramX and everX Posterior (0.42µm). Experimental SFRC had comparable Ra value (0.38µm) than other commercial composites. The presence of short microfibers in the composite appeared to have no adverse effects on the initial adhesion of bacteria or the surface roughness.

The Impact of Modeling Liquids on Surface Roughness and Color Properties of Bulkfill Resin Composites After Simulated Tooth Brushing: An in Vitro Study. Part I.

To evaluate the effect of different modeling agents on color changes, surface roughness, and translucency parameters over time in Bulkfill resin composites. Sixty specimens were prepared using three Bulkfill resin composites (Tetric N-Ceram Bulkfill, Filtek One Bulkfill and Opus Bulkfill) and three modeling agents (Wetting Resin, Optibond FL and Ambar APS). All specimens were subjected to a simulated tooth-brushing (Baseline, 50.000 cycles, 100.000 cycles), and surface roughness was measured at each interval. Surface topography was evaluated. The translucency parameter and color changes were assessed after 24-h, 7-, 14- and 30-day immersion in water, wine, and coffee. Data was analyzed using ANOVA and Bonferroni test. All specimens increased roughness after simulated tooth-brushing (p < 0.05). Wetting Resin decreased roughness on Tetric N-Ceram Bulkfill (p < 0.05). The translucency parameter remained unaltered for all groups. All groups changed color after 30-days of immersion in wine and coffee (p < 0.05). Ambar APS and Wetting Resin on Tetric N-Ceram Bulkfill showed higher color changes when immersed in coffee (p < 0.05). The use of modeling agents does not jeopardize translucency properties but may affect surface roughness and color properties of Bulkfill resin composites depending on their composition. The findings of this study suggest that surface roughness and color properties are affected by the differences in the composition between modeling agents and Bulkfill resins composites.

In Vitro Effects of Sof-Lex, Eve, and Astropol Polishing Systems on Composite Resin Surface Roughness after Aging.

Objectives: Surface roughness is one of the important properties of composite restorations. Different polishing systems are used to provide an appropriate composite restoration surface. The aim of this study was to evaluate the effects of Sof-Lex, Eve, and Astropol polishing systems on composite resin surface roughness after aging. Materials and Methods: In this in vitro study, 36 composite discs (8×2mm) were fabricated. The specimens were randomly divided into three groups (N=12) for polishing with (I) Sof-Lex (3M ESPE), (II) Eve (Ernst Vetter GmbH), and (III) Astropol (Ivoclar/Vivadent) polishing systems. The specimens were then subjected to thermocycling. Surface roughness of the specimens was measured before and after polishing, and after thermocycling by a contact profilometer. Repeated Measures ANOVA was used to analyze the data (α=0.05). Results: Although Astropol showed slightly higher surface roughness in comparison to Sof-Lex and Eve, the level of surface roughness before and after polishing and after aging was not significantly different among the three polishing systems (P=0.704). Conclusion: Within the limitations of this in vitro study, Sof-Lex, Eve, and Astropol showed similar acceptable results with regard to composite resin surface roughness.

Control factor optimization for friction stir processing of AA8090/SiC surface composites

Friction Stir Processing is a state-of-the-art technology for microstructure refinement, material property enhancement, and surface composites fabrication. This investigation concentrates on AA8090/SiC surface composites produced via friction stir processing. Experiments were conducted by varying the following friction stir processing parameters: Tool rotational speed (800–1400 rpm), Tool traverse speed (25–75 mm/min), and Groove width (1.0–1.8 mm). Response measures encompassed Ultimate Tensile Strength and surface roughness. Central Composite Design of Response Surface Methodology designed the experiments and mathematical relationships established between input parameters and ultimate tensile strength and surface roughness. Analysis of variance was used to test the model's adequacy. The models examined individual and interaction effects of input factors on ultimate tensile strength and surface roughness of surface composites. A combinations of input parameters was identified that yields the maximum ultimate tensile strength and minimum surface roughness. The current work employs the friction stir processing approach to synthesis near-net-shaped surface composites without additional machining by systematically optimizing process parameters. Results indicate that increasing tool rotational speed produces well-finished AA8090/SiC surface composites with decreased strength. In contrast, increased tool traverse speed and groove width generate surface composites with rougher surfaces and higher strength. Surface and contour plots further explored the influence of parameter interactions on responses.

Effect of finishing and polishing systems on surface roughness and color stability of aesthetic restorations exposed to staining solution.

The color and the surface roughness of aesthetic restorations are related to the clinical sucess and longevity of these treatments. Aim: This study evaluated the influence of finishing and polishing systems, and storage media on the surface roughness and color stability of aesthetic restorative composites. Materials and Method: Cylindrical specimens (n=10) were prepared and treated according to: 1. Type of composite resin (nanofilled- Filtek Z350XT, suprananofilled- Estelite Omega, nanohybrid- Empress Direct); 2. Type of finishing and polishing systems (no polishing, aluminum oxide discs or abrasive rubber polishers); and 3. Type of immersion medium (water or coffee, 3 h/day/30 days). Surface roughness (Ra - μm) and color stability (L, ΔEab, and ΔE00) were evaluated at baseline (after polishing) and final time (after immersion). Data were subjected to Kruskal-Wallis, Mann-Whitney, Wilcoxon, and Student-Newman-Keuls tests (α=0.05). Results: Nanohybrid (p<0.001) and suprananofilled composite resins (p=0.004) showed an increase in Ra after polishing, regardless the finishing and polishing system. After immersion in coffee, the nanofilled composite had the highest roughness values (p=0.032). L values increased for all resins after polishing (p<0.05). Suprananofilled composites had the greatest color stability with the lowest values of ΔEab and ΔE00. Conclusions: Finishing and polishing systems had an impact on the surface roughness and color stability of all aesthetic resins, and their effectiveness depended on the type of composite resin.

Evaluation of the Surface Roughness and Solubility of Newer Self-blending Composite Resin following Home-bleaching and Brushing-mouth Rinsing Cycle

Objective(s): To evaluate the effect of tooth brushing and mouth rinsing after bleaching with 16% carbamide peroxide (16% CP) on the surface roughness and solubility of newer self-blending resin composite. Materials and Methods: About 70 specimens were fabricated with Estelite sigma-quick composite resin and subjected to bleaching using custom-tray with 16%CP gel for 6hours except 10 samples to serve as control group and divided into seven groups (n=10) as follows: group 1: no bleaching (control), group 2: 16% CP, group 3: brushing, group 4: brushing+Listerine mouth rinse, group 5: brushing +Colgate Plaxmouth rinse, group 6: Listerine, group 7: Colgate Plax. Electric tooth brushing was done using toothpaste slurry for 3min, immersed in mouth-rinse of respective groups for 1min and placed in artificial saliva for 24hrs. This was done for a total period of 21 days followed by surface roughness and solubility testing. Data were statistically analyzed using one-way ANOVA and post hoc Tuckey tests (p&lt;0.05). Results: Group 4 (Brushing + Listerine) showed greater surface roughness and solubility followed by group 6 (Listerine). No significant difference was found between group1 with group3 and group 5. Conclusion (s): Along with brushing, Listerine mouth rinse has a determining effect on surface roughness and solubility of newer self-blending composite resin following bleaching with 16% Carbamide peroxide.

Fabrication and performance optimization of an advanced pervaporation desalination membrane: A study utilizing PVDF and hydrophilic active layer as composite

Pervaporation emerges as a promising technique for brine treatment. In this investigation, we employed a PVDF substrate layer and applied various coating solutions using a simple spray technique to produce a composite pervaporation membrane. The composite membrane's chemical structure, morphology, hydrophilicity, swelling property, surface roughness, and crosslinking conditions were thoroughly investigated. Notably, the PVDF/PEI/P(SS-MA) composite membrane exhibited outstanding desalination performance, demonstrating high salt rejection and flux of 308.7 ± 13.8 kg m−2 h−1 when subjected to a 3.5 wt% sodium chloride solution. Even at an elevated brine concentration of 20 wt%, the membrane maintained a commendable flux of 88.76 ± 5.4 kg m−2 h−1 at 72 °C. These findings underscore the efficacy of the developed composite membrane for brine desalination applications.

Surface roughness of different types of resin composites after artificial aging procedures: an in vitro study

BackgroundThe temperature changes, chemical agents, and brushing activity that resin composite restorations are exposed to in the oral environment can cause changes in surface roughness. In this study, the aim was to investigate in vitro the clinical one-year surface roughness changes of different types of composites (flowable or conventional) from the same companies by subjecting them to immersion in solutions, brushing, and thermal cycling procedures to simulate intraoral conditions.MethodsFour different resin composite brands were included in the study using both their conventional (Charisma Smart, 3M Filtek Ultimate Universal, Omnichroma, Beautifil II) and flowable resin composites (Charisma Flow, 3M Filtek Ultimate Flowable, Omnichroma Flow, Beautifil Flow Plus F00), giving 4 groups with 2 types of resin composite in each. 40 samples were prepared for each group/resin type, for a total of 320 samples. After initial surface roughness measurements by a mechanical profilometer, the samples were divided into 4 subgroups (n = 10) and immersed in solutions (distilled water, tea, coffee, or wine) for 12 days. The samples were then subjected to 10,000 cycles of brushing simulation and 10,000 cycles of thermal aging. Surface roughness measurements were repeated after the procedures. For statistical analysis, the 3-way analysis of variance and the Tukey test were used (p < 0.05).ResultsIt was concluded that composite groups and types had an effect on surface roughness at time t0 (p < 0.001). At time t1, the highest surface roughness value was obtained in the Beautifil-conventional interaction. When the surface roughness values between time t0 and t1 were compared, an increase was observed in the Beautifil II and Beautifil Flow Plus F00, while a decrease was observed in the other composite groups.ConclusionComposite groups, types, and solutions had an effect on the surface roughness of resin composites. After aging procedures, it was concluded that the Beautifil group could not maintain the surface structure as it exceeded the threshold value of 0.2 μm for bacterial adhesion.

Evaluation of the Colour Stability and Surface Roughness of Polymethylmethacrylate and Indirect Composites With and Without Ageing: An In-Vitro Study.

Indirect restorations are a staple restorative option in dentistry due to their versatility, exceptional aesthetics, and desirable strength and longevity.Metal ceramics and all ceramics are the material of choice for permanent restorations but come with certain disadvantages, such as chipping, fracture, and wear of the antagonist tooth or restoration.Polymethylmethacrylate (PMMA) and indirect composite resins are commonly usedmaterials due to their favourable properties for temporary restorations, but lately, they have been chosen as the restorative material of choice for implant-supported full-mouth rehabilitations. This study aimed to evaluate and compare the colour stability and surface roughness of PMMA and indirect composite resins under both ageing and non-ageing conditions. This would greatly help a clinician in choosing materials depending on the clinical scenarios. This study aims to evaluate the colour stability and surface roughness of PMMAand indirect composite resins with and without ageing. Specimensof PMMA and indirect composite resins were fabricated and subjected to an ageing process involving thermocycling in the TW-C4.4 (Tae-Won Tech, Incheon, Korea)and immersion in a staining solution. Colour stability was assessed using a spectrophotometer (SpectraMagic NX, RM2002QC, Konica Minolta Corp., Ramsey, Japan), and surface roughness was measured using a stylus profilometer (Mituyoto, Mituyoto Corporation, Kawasaki, Japan). Statistical analysis was performed using IBM SPSS Statistics for Windows, Version 24 (Released 2016; IBM Corp., Armonk, New York) to determine significant differences between materials and ageing effects. PMMA exhibited significantly higher colour changes and increased surface roughness post-ageing compared to indirect composite resins. The findings underscored PMMA's susceptibility to discolouration and surface degradation under thermal stress conditions. PMMA demonstrates inferior colour stability and increased surface roughness following thermocycling compared to indirect composite materials, suggesting careful consideration in material selection for provisional restorations. Further research should explore additional ageing processes and materials to enhance understanding and improve clinical outcomes.

The effect of whitening toothpastes on the color stability and surface roughness of stained resin composite

BackgroundThis study aimed to investigate the effect of whitening toothpastes on the color stability and surface roughness of resin composites stained with coffee and cigarette smoke.MethodsSeventy-two disk-shaped specimens (6 × 2 mm) of suprananohybrid resin composite were randomly divided into two groups and exposed to coffee and cigarette smoke (n = 36). After staining, the samples randomly divided into four groups according to whitening toothpastes and were brushed for 4 min: Opalescence Whitening (OW); Colgate Optic White (COW); Curaprox Black is White (CPX) and, distilled water (control) (n = 9). Color was measured with spectrophotometer at the initial, after staining, and after brushing, and surface roughness was measured with profilometer at the initial and after brushing. A surface morphology analysis was examined using scanning electron microscopy and atomic force microscopy. The obtained data were statistically analyzed. (p < 0.05).ResultsCigarette smoke caused a significantly higher color change than coffee in the resin composite (p < 0.05). Brushing with hydrogen peroxide and silica-containing whitening toothpaste showed significant differences in color change (p < 0.05). The lowest whitening effect was found in activated charcoal-containing toothpaste. While all toothpastes increased the degree of surface roughness of resin composites, the highest roughness was caused by whitening toothpastes containing activated charcoal. (p < 0.05).ConclusionsThe color stability and surface properties of resin composites can be affected by brushing them with whitening toothpaste. The utilization of whitening toothpaste containing hydrogen peroxide can be considered a safe method for increasing the whiteness of discolored resin composites.

Effect of Polishing Systems on the Surface Roughness and Color Stability of Aged and Stained Bulk-Fill Resin Composites.

The aim of this study is to investigate how two different polishing techniques affect the color stability, surface roughness, and changes in surface morphology of aged and coffee-stained bulk-fill resin composites. A total of 112 disc-shaped samples were prepared using Omnichroma Flow Bulk (OB), Charisma Bulk Flow One (CB), Estelite Bulk Fill Flow (EB), and Estelite Sigma Quick (control). Samples were divided into two subgroups (n = 16) and aged using thermocycling. A profilometer was used to measure the surface roughness (Ra) and a spectrophotometer was used for color stability (ΔE00). The EB group had the highest Ra values both before aging (disc: 0.23 ± 0.05, twist: 0.42 ± 0.05) and after aging (discs: 0.28 ± 0.04, twist: 0.46 ± 0.05). The OB group had the highest ΔE00 values before and after aging (discs: 3.06 ± 0.54, twist 3.05 ± 0.41) and the highest after coffee-staining (discs: 3.75 ± 0.70, twist: 3.91 ± 0.57). Re-polishing reduced the ΔE00 values in all materials but did not restore all to clinically acceptable levels. According to the results of this study, it can be concluded that the surface roughness and color stability of resin composites are notably influenced by the polishing technique, aging process, and coffee staining. Specimens that were polished using the multi-stage Super-Snap discs consistently exhibited smoother surfaces across all bulk-fill resin composites compared to those polished with the two-stage Diacomp plus Twist.

Influence of in-office whitening on the color matching and surface characteristics of single-shade resin composites.

The color matching of single-shade resin composites after in-office whitening was investigated. Four single-shade resin composites were used. A total of 35% hydrogen peroxide was used as the whitening agent. The resin composite was placed in a cavity of an artificially discolored bovine tooth. The color differences between the restoration and surrounding enamel before and after whitening were determined based on ΔE*ab, ΔE00, and ΔWID. The color stability, surface roughness (Sa), and surface gloss (GU) of the resin composite alone were also evaluated. Statistical analyses were performed using repeated-measures analysis of variance with the Tukey-Kramer test. Based on the 50:50% of perceptibility and acceptability thresholds of ΔE*ab and ΔE00, none of the resin composite restorations were clinically acceptable before or after whitening. Regarding ΔWID, although all resin composites showed "acceptable match" in the baseline, they showed "mismatch" after the third session of whitening. Most of the resin composites alone were stable in color against whitening. Although the single-shade resin composites failed to achieve the expected color matching on discolored teeth either before or after the whitening, the impact of the whitening on the color of the resin composite alone may be negligible.