1 Volume 23 2024 e241390 Original Article Braz J Oral Sci. 2024;23:e241390http://dx.doi.org/10.20396/bjos.v23i00.8671390 1 Department of Restorative Dentistry, University of Pernambuco, Recife, PE, Brazil. 2 Department of Restorative Dentistry, Federal University of Paraíba, João Pessoa, PB, Brazil. 3 Department of Restorative Dentistry, Faculty of Nova Esperança , João Pessoa, PB, Brazil. Corresponding author: Caroline de Farias Charamba Street Joaquim Ferreira da Costa, 40 58038-540, João Pessoa, PB, Brazil Phone: 55 83-996074931 E-mail: carolfariasch21@gmail.com Editor: Altair A. Del Bel Cury Received: Nov 03, 2022 Accepted: Aug 19, 2023 Color and surface roughness alterations of bulk-fill resin composites submitted to simulated toothbrushing with whitening dentifrices Caroline de Farias Charamba1* , Mariana Melani Alexandrino Costa2 , Renally Bezerra Wanderley e Lima3 , Rosângela Marques Duarte2 , Marcos Antonio Japiassú Rezende Montes1 , André Ulisses Dantas Batista2 , Ana Karina Maciel Andrade2 Aim: To evaluate the surface roughness and color stability of bulk-fill resin composites after simulated toothbrushing with whitening dentifrices. The radioactive/relative dentin abrasion (RDA) and radioactive/relative enamel abrasion (REA) of dentifrices were also assessed. Methods: Specimens (n=10) of Tetric N Ceram Bulk Fill (TNCB), Filtek One Bulk Fill (FOB) resin composites, and Z100(Control) were prepared using a cylindrical Teflon matrix. Surface roughness (Ra, μm) was assessed by a roughness meter and the color evaluations (ΔEab, ΔE00, WID) were performed using a digital spectrophotometer based on the CIELAB system. Three measurements were performed per sample, before and after simulated toothbrushing with 3D Oral-B White Perfection (3DW) and Black is White (BW) dentifrices. The abrasivity (REA and RDA values) of the used dentifrices was also determined by the Hefferren abrasivity test. Results: The Ra values increased significantly in all resin composites after 3DW and BW toothbrushing. The acceptable threshold color varied among resin composites, and TNCB and Z100 presented the highest ΔEab and ΔE00 for BW dentifrice. The 3DW dentifrice was significantly more abrasive than BW dentifrice on enamel and dentin. Conclusions: simulated toothbrushing with tested whitening dentifrices increased the surface roughness at acceptable levels. The Tetric N Ceram Bulk-fill and Z100 composite showed the highest color alteration in BW. 3D White Perfection dentifrice was more abrasive on dentin and enamel than Black is White. Keywords: Composite resins. Dentifrices. Bleaching agents. https://orcid.org/0000-0002-5811-1796 https://orcid.org/0000-0002-9491-932X https://orcid.org/0000-0003-4477-7850 https://orcid.org/0000-0003-4369-2951 https://orcid.org/0000-0002-1197-9985 https://orcid.org/0000-0003-1593-0174 https://orcid.org/0000-0003-4520-5176 2 Charamba et al. Braz J Oral Sci. 2024;23:e241390 Introduction Conventional composites restore tooth cavities in increments of 2 mm, reducing tension during polymerization contraction and improving light absorption1,2. How- ever, the conventional technique is time-consuming and increases operative error, leading to gaps, decreased bond strength, and early restoration fracture3. These limitations allowed the emergence of bulk-fill restorative composites, which can be inserted in increments of 4 to 5 mm, decreasing the sensitivity of the technique4-6. They are also clinically comparable to conventional restorative composites regard- ing anatomical shape, color, marginal changes, secondary caries, postoperative sensitivity, and retention7. Some Bulk-fill composites may have a better adaptation to cavity walls8, although there are not enough data to explore the relationship between the use of this material and microleakage, they are innovative materials for conservative dentistry that can reduce treatment steps and duration of operative times9. Laboratory studies indicate similar or better performance of these materials compared to conventional ones in terms of polymerization stress, degree of conversion, and resistance to bending and fracture10. Current studies demonstrate that the clinical performance of conventional resins and bulk-fill resins for carious lesion restorations is similar11, including longevity in posterior permanent teeth12. Toothbrushing exposes restorative materials in the oral cavity to changes in surface properties13. Currently, new whitening techniques, including “over-the-counter” whiten- ing agents (e.g., dentifrices and mouthwashes)14, have arisen, exempting professional supervision. Whitening dentifrices with abrasive and chemical agents, such as chalk, silicate, bentonite, or peroxide, may promote adverse effects on soft and hard tissues. Meanwhile, whitening-abrasive dentifrices compromise teeth’ mineral structure, mis- characterizing enamel prisms15. 3D White perfection (Oral B) is one of the tooth whitening dentifrices found on the market responsible for tooth wear16. Its whitening process occurs due to hydrated silica and mica (crystallized minerals used as micro polishing system) and hexamet- aphosphate, capable of adsorption on the dental surface16. An activated carbon denti- frice (Black is White, Curaprox) was also manufactured to minimize the abrasive and chemical effects of most whitening dentifrices17. Although activated carbon-based dentifrices are legally marketed to whiten teeth, scientific evidence proving the real whitening effect is limited and still insufficient to prove the cosmetic benefit of these products. ‘Black is White Curaprox® dentifrice was less effective than other whitening dentifrices in reducing extrinsic stains18. Laboratory studies on abrasion are important to the development of new denti- frice formulations, evaluation the quality control, and estimate of clinical abrasiv- ity. Individual behavioral differences in toothbrushing affect the abrasivity of denti- frices19,20. Abrasion values of dentifrices can be measured using radioactive/relative dentin abrasion (RDA) and radioactive/relative enamel abrasion (REA), and prac- titioners should consider both values when recommending dentifrices to prevent tooth wear21. 3 Charamba et al. Braz J Oral Sci. 2024;23:e241390 Although there is evidence of acceptable results for wear and surface roughness of bulk-fill composites, comparable to conventional composites, when brushed with a non-whitening dentifrice, the brushing time and composition of the denti- frices used must be considered, since attrition and abfraction can affect the ser- vice life of restorations22. After toothbrushing, changes in surface color and rough- ness of composite resins are related to the interaction between the composition of bulk-fill resins and characteristics of the whitening dentifrice23. Furthermore, the increased surface roughness may contribute to bacterial adhesion and dental biofilm maturation24. The evaluation of the performance of different dentifrices has already demonstrated greater abrasiveness of whitening dentifrices compared to the conventional one25. Increased roughness has already been observed in both whitening and conventional dentifrices, and both had similar effects on tooth enamel color26. Therefore, this study aimed to evaluate the surface roughness and color stability of bulk-fill composites after simulated toothbrushing with whitening dentifrices. REA and RDA of dentifrices 3D White Perfection (containing polishing microparticles) and Black is White (containing activated carbon) were also assessed. The following null hypotheses were tested: 1) surface roughness of restorative composites is not differ- ent after simulated toothbrushing; 2) surface color is not different between compos- ites after simulated toothbrushing. Material and Methods Study design Sixty specimens were randomized into three groups according to the resin com- posite materials: Z100/positive control (3M ESPE, St. Paul, MN, EUA), Tetric N Ceram Bulk-Fill (TNCB) (Ivoclar ivadent, Schaan, Liechtenstein), and Filtek One Bulk- Fill (FOB) (3M ESPE, St. Paul, MN, EUA). Each group underwent simulated tooth- brushing with two types of whitening dentifrices (n=10): 3D Oral-B White Perfection (3DW) (Procter & Gamble Manufactura, Manaus, AM, Brazil) and Black is White (BW) (Curaprox, Curaden International AG, Kriens, Switzerland). Surface roughness and color stability were measured at baseline and after 10,000 toothbrushing cycles. In the study’s second phase, dentifrices were tested for REA and RDA (n=8) using the Hefferren abrasivity test27. Specimen preparation Twenty specimens of each composite were prepared using a cylindrical Teflon matrix (2mm thick and 6 mm in diameter) (Table 1). Single increments of restorative mate- rial filled the matrix, and then a polyester strip with a glass plate flattened the surface to avoid bubble formation. Specimens were polymerized using Emitter C equipment (SCHUSTER, Santa Maria, RS, Brazil), with light intensity above 800 mW/cm² accord- ing to an RD-7 radiometer reading (ECEL, Ribeirão Preto, SP, Brazil). Light-curing time was 20 seconds, according to the recommendations of the manufacturer. Subse- quently, specimens were immersed for 24 hours in distilled water. 4 Charamba et al. Braz J Oral Sci. 2024;23:e241390 Table 1. Manufacturer, trade name, and composition of restorative composites and whitening dentifrices used in the study. Manufacturer Composite Composition 3M ESPE/ St. Paul, MN, EUA Z100 Color A3 Treated silanized ceramic (80-90% by weight), TEGDMA, BisGMA, 2-Benzotriazolyl-4-methylphenol (0.1416-0.145% by weight). Average particle size: 0.6 µm. Ivoclar-Vivadent, Bendererstrasse Schaan, Germany Tetric N Ceram Bulk-fill Color A3 Bis-GMA, Bis-EMA e UDMA (19-21% by weight) and 75-77% by weight (53-55% by volume) inorganic particles (average: 0.6 µm). Filler consists of barium glass, prepolymer, ytterbium trifluoride, and mixed oxides. Inorganic fillers particles sized 0.04 to 3 μm. 3M ESPE/ St. Paul, MN, EUA Filtek One Bulk-fill Color A3 AUDMA, UDMA, and 1,12-dodecane-DMA. Zirconia (4-11 nm) and silica (20 nm) may be aggregated and agglomerated. Ytterbium trifluoride from agglomerated particles (100 nm); 76.5% by weight (58.4% by volume) (CURAPROX) Amlehnstrasse, Kriens, Switzerland Black is White Water, sorbitol, hydrated silica, glycerin, charcoal powder, flavor, decyl glucoside, cocamidopropyl betaine, sodium monofluorophosphate (950 ppm), tocopherol, xanthan gum, maltodextrin, mica, hydroxyapatite (nano), acesulfame potassium, titanium dioxide, microcrystalline cellulose, sodium chloride, potassium chloride, citrus lemon peel oil, sodium hydroxide, zea mays starch, amyloglucosidase, glucose oxidase, urtica dioica leaf extract, potassium thiocyanate, cetearyl alcohol, hydrogenated lecithin, mentyl lactate, methyl diisopropyl propionamide, ethyl menthane carboxamide, stearic acid, mannitol, sodium bisulfite, tin oxide, lactoperoxidase, and limonen. (P&G) Cincinnati, Ohio, EUA 3D White Perfection Oral-B Sodium fluoride (1100 ppm fluoride), glycerin, hydrated silica, sodium hexametaphosphate, water, PEG-6, flavor, trisodium phosphate, sodium lauryl sulfate, carrageenan, cocamidopropyl betaine, mica (CI 77019), sodium saccharin, PEG-20M, xanthan gum, titanium dioxide (CI 77891), sucralose, limonen, pigment blue 15 (CI 74160). TEGDMA: triethylene glycol dimethacrylate; Bis-GMA: bisphenol A glycidyl methacrylate; UDMA: urethane dimethacrylate; Bis-EMA: bisphenol A polyethylene glycol dimethacrylate; AUDMA: aromatic urethane dimethacrylate. Surface roughness Surface roughness (Ra, μm) was assessed using a roughness meter (Surftest SJ-301, Mitutoyo, Japan). Specimens were individually fixed on a glass plate with utility wax, and three random roughness readings were taken per sample, before and after the simulated toothbrushing. Mean roughness values were calculated and included in the data analysis. For surface roughness readings, Ra was adjusted to translate the absolute distances of the roughness profile from the centerline, within the Lm measurement (measure- ment limit). Equipment parameters were standardized using the following test condi- tions: Lc (cut-off/filtering, minimizing the interference of surface ripple) - 0.25 mm and speed of 0.5 mm/s. Readings considered the mean between peaks and valleys (Ra), covered in a trajectory performed by the mechanical probe (4.0 mm)28. Color Evaluations Color evaluations were performed using a digital spectrophotometer (Vita Easyshade, Vita Zahnfabrik, Bad Säckingen, Germany). Colors measurements were performed by positioning specimens on a white background to prevent potential absorption effects 5 Charamba et al. Braz J Oral Sci. 2024;23:e241390 on color parameters. Three measurements were performed per sample so that the active tip of the spectrophotometer reached the center of each specimen before (baseline) and after the simulated toothbrushing (10,000 cycles). Mean color values were calculated and included in data analysis28. The first color evaluation was based on the CIELAB system. For this, a color space system determines color in a three-dimensional space, where L* represents the lightness, a* measures red (positive) or green (negative) colors, and b* measures yellow (positive) or blue (negative) colors. Color differences (ΔEab) between coordi- nates were calculated by ΔEab = [(ΔL)2+ (Δa)2+ (Δb)2]1/2 to compare values before and after treatment29. To analyze the color differences perceived by the human eye, the ΔE00 (CIEDE2000) calculation was performed according to the equation: [(ΔL’/KLSL) 2 + (ΔC’/KCSC) 2 + (ΔH’/ KHSH) 2 + RT (ΔC’/ KCSC) (ΔH’/KHSH)]½. Where ΔL’, ΔC’, and ΔH’ are the differences in Lightness, Chroma, and Hue for a pair of specimens, and RT is a function that accounts for the interaction between Chroma and Hue differences in the blue region. Weighting functions SL, SC, and SH adjust the total color difference for variation in the location of the color difference pair, and KL, KC, and KH are empirical terms used for correcting (weight- ing) the metric differences to the CIEDE2000 differences for each coordinate30,31. The interpretation of color differences among tooth-colored materials through 50:50% perceptibility (PT) and 50:50% acceptability threshold (AT) was based on the results reported in References32,33 (Table 2). Table 2. 50:50% perceptibility (PT) and 50:50% acceptability threshold. Threshold Rating and interpretation ΔE00 ΔEab ≤PT (5) Excellent match ≤0.8 ≤1.2 >PT, ≤AT (4) Acceptable match >0.8, ≤1.8 >1.2, ≤2.7 >AT, ≤AT × 2 (3) Mismatch type [a] >1.8, ≤3.6 >2.7, ≤5.4 >AT × 2, ≤AT × 3 (2) Mismatch type [b] >3.6, ≤5.4 >5.4, ≤8.1 >AT × 3 (1) Mismatch type [c] >5.4 >8.1 Mismatch types: [a] = moderately unacceptable; [b] = clearly unacceptable; and [c] = extremely unacceptable. The whitening index for dentistry (WID) was also calculated, with the parameters L*, a*, and b* being used in the equation30 WID = 0.511L* - 2.324a* - 1.100b*. The differences in WID between the initial and final measurements were analyzed to obtain the ΔWID, considering the perceptibility threshold and acceptability 0.72 and 2.60, respectively34. Simulated toothbrushing A toothbrushing machine (Biopdi, São Carlos, Brazil) composed of ten arms articu- lated by pulleys and with back-and-forth movements performed the simulated tooth- brushing. Sixty toothbrushes with straight soft bristles (Oral-B Indicator Plus 35 P&G Cincinnati, Ohio, USA; one/sample) were adapted to the equipment by sectioning handles at intermediary height, leaving the long axis of bristles perpendicular and in 6 Charamba et al. Braz J Oral Sci. 2024;23:e241390 contact with specimens embedded in acrylic resin. For the abrasivity test, 30 tooth- brushes were combined with each dentifrice (BW or 3DW). Dentifrices (Table 1) were suspended and diluted in distilled water (3:1 ratio) using a mechanical stirrer. Samples were subjected to 10,000 cycles at 4 Hz frequency (240 toothbrushing per minute) and an axial load of 200 g. After toothbrushing, specimens were removed, rinsed under running water, and immersed in distilled water. Abrasivity testing of dentifrices The abrasivity of dentifrices was verified using the Hefferren abrasivity test, recom- mended by the American Dental Association (ADA) and Organization for Standardiza- tion (ISO) 11609. ISO specifies a limited abrasivity from the standard reference mate- rial (Ca2P2O7) of 2.5x for dentin and 4x for enamel. Therefore, arbitrary values of 100 (limit of 250) and 10 (limit of 40) were assigned for dentin and enamel, respectively. The ratio between standard and tested materials was calculated. Samples of dentin and enamel from human teeth were subjected to neutron bom- bardment, resulting in radioactive phosphorus (32P) formation under controlled con- ditions described by ADA. Subsequently, samples were assembled in methyl methac- rylate and coupled to a V-8 cross-brushing machine. After exposition to solutions of standard reference material (10g) and 0.5% carboxymethyl cellulose (CMC) glycerin (50 mL), dentin samples were subjected to 1,500 toothbrushing cycles and enamel samples to 5,000 toothbrushing cycles, following a “sandwich design”. Bristles fol- lowed ADA specifications, with a load of 150 g. Each set of teeth was brushed with the standard reference material (10 g Ca2P2O7/ 50 mL at 0.5% CMC) before and after toothbrushing with the product under test (25 g product/40 mL water). This procedure was repeated to test products on all teeth, with modified Latin squares design to avoid interaction of factors. A scintillation cocktail of “Ultima Gold” (5 mL) was added to the weighted sample (1 mL). The sample was mixed and immediately placed in a liquid scintillation counter for radiation detection. After counting, liquid values per minute (CPM) were divided by sample weight to calculate liquid CPM/gram of dentifrice (CPM/g). Net CPM/g of anterior and posterior standard reference material for each dentifrice was calculated, and the mean value was used to calculate RDA and REA. Statistical Analysis Color evaluation and surface roughness values were compared using Kruskal-Wallis test pairwise comparison and the Wilcoxon test. Relative abrasion data were analyzed using one-way ANOVA (IBM statistics software SPSS, USA), and additional pairwise comparisons were performed using the Student-Newman-Keuls posthoc test. The significance level was set at 0.05 (2-sided). Results Surface roughness increased significantly in all composites after 3DW toothbrush- ing, but with no differences between composites. Regarding BW, all composites also 7 Charamba et al. Braz J Oral Sci. 2024;23:e241390 increased surface roughness after toothbrushing. However, surface roughness was significantly higher in FOB after toothbrushing (Table 3). Table 3. Mean and standard deviation of roughness (µm) before and after toothbrushing with 3DW (Oral B) and BW (Curaprox) dentifrices. 3DW Z100 TNCB FOB BEFORE 0.10 (0.01)Aa 0.10 (0.01)Aa 0.11 (0.01)Aa AFTER 0.19 (0.01)Ba 0.22 (0.04)Ba 0.20 (0.02)Ba BW Z100 TNCB FOB BEFORE 0.10 (0.02)Aa 0.10 (0.01)Aa 0.11 (0.01)Aa AFTER 0.19 (0.02)Ba 0.15 (0.01)Ba 0.24 (0.03)Bb Different uppercase letters in the same column indicate statistically significant differences before and after within the same group. Different lowercase letters in the same row indicate statistically significant differences between groups. Table 4 and Table 5 show the color parameters of composites brushed with 3DW and BW respectively. The L* color parameters decreased in almost all groups, except in FOB (3DW). The b* color parameters decreased or remained stable in 2 dentifrices. The color varied among composites, TNCB presented the highest ΔEab and ΔE00 (Figure 1) for both dentifrices, although no difference from Z100 (BW). Table 4. Mean ±standard deviation L*, a*, and b* values of specimens before and after toothbrushing with Oral B (3DW) and Curaprox (BW) dentifrices. Color dimension Oral B dentifrice (3DW) Resin composite BEFORE AFTER L* Z100 82.11 (1.32)Aa 80.64 (1.16)Ab TNCB 87.72 (1.42)Ba 87.47 (1.38)Bb FOB 85.48 (1.62)Ba 87.16 (1.40)Bb a* Z100 2.95 (0.19)Aa 2.89 (0.11)Aa TNCB -0.77 (0.21)Ba -0.57 (0.18)Bb FOB 1.80 (0.13)Ca 1.65 (0.12)Cb b* Z100 26.33 (0.68)Aa 25.71 (0.62)Ab TNCB 17.81 (0.73)Ba 14.82 (0.57)Bb FOB 25.81 (0.51)Aa 25.75 (0.40)Aa Color dimension Curaprox dentifrice (BW) Resin composite BEFORE AFTER L* Z100 81.69 (0.86)Aa 76.78 (1.14)Ab TNCB 86.52 (1.46)Ba 81.08 (1.71)Bb FOB 84.39 (1.44)Ba 83.69(1.37)Bb Continue 8 Charamba et al. Braz J Oral Sci. 2024;23:e241390 Continuation a* Z100 2.84 (0.10)Aa 2.79 (0.10)Aa TNCB -0.75 (0.30)Ba -0.19 (0.32)Bb FOB 2.03 (0.13)Ca 1.94 (0.12)Ca b* Z100 25.83 (0.47)Aa 25.66 (0.53)Aa TNCB 18.15 (0.81)Ba 14.93 (0.32)Bb FOB 26.77 (0.52)Aa 25.12 (0.49)Ab Different uppercase letters in the same column indicate statistically significant differences between groups. Different lowercase letters in the same row indicate statistically significant differences before and after within the same group. Table 5. Mean ± standard deviation color variation (ΔEab, ΔE00, WID). Color variation Oral B dentifrice (3DW) Z100 TNCB FOB ΔEab 1.66 (0.66)a 3.02 (0.36)b 1.76 (0.31)a ΔE00 1.07 (0.42)a 1.76 (0.19)b 1.12 (0.24)a ΔWID 0.05 (0.79)a 2.68 (0.65)b 1.26 (0.56)a Color variation Curaprox dentifrice (BW) Z100 TNCB FOB ΔEab 4.91 (0.82)a 6.37 (0.57)a 1.82 (0.29)b ΔE00 3.42 (0.59)a 4.12 (0.40)a 0.91 (0.16)b ΔWID -2.17 (0.62)a -0.55 (0.59)b 1.66 (0.38)c Different lowercase letters in the same row indicate statistically significant differences between groups. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Z100 CI ED E 20 00 (∆ E0 0) 3DW BW PT AT FOBTNCB Figure 1. Mean and standard deviation values of ΔE00 between different groups. 9 Charamba et al. Braz J Oral Sci. 2024;23:e241390 The interpretation of color differences among tooth-colored materials through 50:50% perceptibility (PT) and 50:50% acceptability threshold (AT) for the Oral B (3DW) denti- frice was: ΔEab: Z100 and FOB was classified as an acceptable match; for TNCB was mismatch type (moderately unacceptable); ΔE00: was classified acceptable match for three materials. For Curaprox (BW) dentifrice was ΔEab: Z100 was mismatch type (moderately unacceptable); FOB was classified as an acceptable match; TNCB was mismatch type (clearly unacceptable); ΔE00: Z100 was mismatch type (moderately unacceptable); FOB was classified acceptable match; TNCB was mismatch type (clearly unacceptable). As for the whiteness index, considering the classification of 50:50% whiteness percep- tibility threshold (WPT), TNCB and FOB showed a noticeable color change with Oral B dentifrice (3DW), and Z100 and FOB showed a noticeable color change with Curaprox (BW). Still, considering the classification of 50:50% whiteness acceptability threshold (WAT), with Oral B dentifrice (3DW), the TNCB result was clinically unacceptable and with Curaprox (BW), Z100 and TNCB showed a tendency to darken (ΔWID negative). Table 6 shows RDA and REA values, where mean values (± standard deviation) are listed in descending order (high mean values of RDA and REA represent high abra- sivity). The 3DW dentifrice was significantly more abrasive than BW dentifrice on enamel and dentin. Table 6. Mean and standard deviation of abrasivity on dentin and enamel. Dentifrices Sample size (n=8) RDA REA Oral-B 3D White Perfection 8 189.82 (3.66)A 9.68 (0.69)A CURAPROX Black is White Frest Lime-mint 8 116.30 (2.39)B 3.14 (0.34)B Different uppercase letters in the same column indicate statistically significant differences (p<0.05) between dentifrices. Discussion This study evaluated the surface roughness and color stability of bulk-fill composites after simulated toothbrushing with whitening dentifrices (3D Oral-B White Perfection and CURAPROX Black is White). Our hypotheses were rejected once surface rough- ness and color changed after abrasion. Evaluated composites showed an increase in surface roughness after simulated brushing, thus rejecting the first null hypothesis. This effect was already expected for both conventional and bulk-fill composites13,35-37 due to toothbrushing movements, which compromise the finishing and polishing of surface layers by wearing and alter- ing surface topography38. The Ra values after brushing with 3DW were not different between composites. However, FOB presented the most pronounceable increase in surface roughness after brushing with BW, differing from Z100 (conventional com- posite). This may be related to the fact that the FOB resin is nanohybrid, and contains a mixture of nanoparticles and larger irregular particles, a fact that can cause greater irregularity before wear35. Nevertheless, surface roughness was not clinically relevant 10 Charamba et al. Braz J Oral Sci. 2024;23:e241390 in the present study, since alterations ranged between 0.10 and 0.24 µm. Roughness values higher than 0.2 µm would increase biofilm accumulation, secondary caries, and periodontal inflammation38. Some authors also consider changes in roughness from 0.22 to 0.24 µm as clinically irrelevant39. The use of CIEDE2000 for the study of color stability is recommended due to its greater agreement (95%) with visual findings, that is, it can better represent the human perception of color change33. Regarding color parameters, L* indicates the luminosity of an object (zero being total black or 100 total white), a* indicates the red (+a) and green (-a) axis, and b* indicates the yellow (+b) and blue (-b) axis37. Values of a* and b* close to zero represent white or gray colors, while the opposite occurs with saturated colors, in which values are high40. When color is evaluated after whitening, L* values are expected to increase and b* values decrease41. The latter parameter is probably more affected by whitening effects than L* values41. Our findings revealed that b* val- ues decreased or remained stable It was observed that the L* values decreased more when BW than 3DW dentifrice was used. This may be justified by the fact that the 3DW toothpaste proved to be more abrasive than BW, according to the RDA and REA values found in this study. The literature shows a relationship between the degree of abrasiveness of whiten- ing dentifrices and the ability to polish the surface and improve brightness (>*L)42. Another hypothesis is that the dark color of the BW toothpaste may have stained the restorative materials tested.  Torso et al.43 (2021), concluded that color change and surface wear shown by charcoal dentifrices may compromise the longevity of restorations. This study showed that charcoal-based dentifrices resulted in greater color change than conventional dentifrices. The charcoal made the composite resin darker in color. The perceptibility threshold (PT) is related to the smallest color difference that can be detected by an observer. The 50:50% perceptibility threshold is equivalent to a situa- tion in which 50% of the evaluators notice a difference in color between the two eval- uated objects (eg dental restorations) while the other 50% do not notice a difference. Thus, the color difference that is acceptable for 50% of the observers corresponds to the 50:50% acceptability threshold (AT)33. According to Paravina et al.32 (2015), it is possible to correlate the visual thresholds with the findings of laboratory and clinical studies, as shown in Table 2. The present study revealed that the ΔEab value of the TNCB resin brushed with the 3DW dentifrice corresponded to a moderately acceptable classification, while the ΔE00 was considered an acceptable correspondence. When brushed with the BW dentifrice, the TNCB resin, both ΔEab, and ΔE00 were classified as clearly unacceptable. The ΔEab and ΔE00 values of the Z100 resin brushed with the BW dentifrice were moderately unacceptable. Torso et al.43 (2021) reported that BW dentifrice caused a noticeable change in the color of the Z350 resin after 417 brushing cycles and a change outside the acceptable range after 5004 brushing cycles. The organic phase and low amount of filler particles of TNCB may increase pigment incorporation (evidenced by worst ΔEab)44. According to Trevisan et al.44, the TNCB resin showed the worst color stability probably because of the volumetric distribution 11 Charamba et al. Braz J Oral Sci. 2024;23:e241390 between the organic and inorganic phases; however, it is unknown whether this pig- mentation occurs clinically due to limitations of in vitro studies. Color stability is related to the hydrophilic capacity of the resin matrix. When evaluat- ing the composition of the tested resins, it is possible to observe that the TNCB resin has in its formulation the Bis-GMA known to have a greater affinity for water than the AUDMA45 present in the FOB composite resin. This fact may explain the lower color stability of this composite resin in the present study after brushing with 3DW and BW dentifrices. It was reported that the Bis-GMA‐based resin matrix has higher water sorption due to its hydrophilicity which is leading to less stain resistance compared to other methacrylate monomers46,47. However, the Z100 resin after brushing with the BW dentifrice showed a moderate incompatibility, these differences are probably related to the organic matrix composition since TEGDMA and Bis-GMA are hydrophilic monomers, which are more susceptible to pigment incorporation48. Furthermore, increasing the amount of TEGDMA in the resin matrix from 0 to 1% resulted in the increased water uptake of Bis-GMA‐based resins46. Barutcugil et al.49 reported that bulk-fill resin composite containing Bis-GMA and TEGDMA monomers, presented the highest color change after immersion in beverages when compared to nanohybrid resin composites49. Mada and other authors50 (2018), reported that color alterations in hybrids resins composites can be measured by evaluating the whiteness index. Considering the values obtained by applying the index, the FOB composite presented a perceptible color change after treatment with the two dentifrices (Oral B 3DW and Curaprox BW). In the study by Backes et al.48 (2020), when evaluating the performance of con- ventional Filtek and bulk-fill resins in terms of color stability, it was concluded that the conventional composite showed greater color alterations when a darkening test was used. In the present study, Z100 (conventional) and TNCB were the only com- posites that showed negative ΔWID values after brushing with Curaprox BW, indi- cating a lower bleaching index in the post-treatment evaluation, representing the darkening of the sample51. High dentin abrasivity in whitening dentifrices was already expected21. The 3DW dentifrice showed higher RDA and REA values than BW; according to RDA values, high abrasivity values range from 151 to 250, 3DW showed approximately 189 RDA value, and medium abrasivity from 70 to 150, 3DW showed approximately 116 RDA value21, respectively. Machla et al.52 also classified the charcoal-based denti- frice as medium abrasive and Koc et al.26 found no change in the surface roughness after brushing with BW dentifrice. Hamza et al.53 observed the same cleaning efficacy between BW and conventional abrasive dentifrices, but less dentin wear. Therefore, the need for a higher level of abrasivity is questioned since low and high abrasivity pre- sented similar cleaning efficacy. Highly abrasive dentifrice can lead to wear in regions affected by incipient caries, especially when brushing frequency is increased54 Philpotts et al.55 investigated the in vitro enamel and dentin wear by dentifrices with different levels of abrasivity. The relationship between REA and enamel wear was not determined due to the limited abrasiveness of the products tested, but a good cor- relation between dentin wear and RDA was found. Although in vitro studies control 12 Charamba et al. Braz J Oral Sci. 2024;23:e241390 exposure time, temperature and acidity of the environment, and type of agent and substrate, only trends and indications on wear extension are obtained once biological variations of the oral environment cannot be fully replicated56. Few studies regarding the color stability and surface roughness of bulk-fill compos- ites evaluated whitening dentifrices with activated carbon. The present in vitro study provides new knowledge regarding the abrasivity potential of whitening dentifrices and their effects on the optical and surface properties of bulk-fill composites. How- ever, further in vitro and in vivo studies are advised to consolidate our results, confirm changes, and evaluate the longevity and efficacy of bulk-fill composites against tooth- brushing with whitening dentifrices. Also, the comparison of whitening and no-whit- ening dentifrices is advised. Conclusion The roughness of all composites increased to acceptable levels after brushing with 3DW and BW dentifrices. The Tetric N Ceram Bulk-fill resin showed greater color change after simulated tooth- brushing, with a classification of clearly unacceptable when BW dentifrice was used; the Z100 resin composite associated with the BW dentifrice resulted in moderately unacceptable changes. Both showed a tendency to darken. The 3D White Perfection dentifrice was more abrasive on dentin and enamel than Black is White. Conflict of interests None. Data availability Datasets related to this article will be available upon request to the corresponding author. Authors Contribution Caroline de Farias Charamba: Substantial contributions to the conception and design of the work; Acquisition, analysis and interpretation of data for the work; Drafting the work and revising it critically for important intellectual content; Final approval of the version to be published; Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. Mariana Melani Alexandrino Costa: Acquisition of data for the work; Drafting the work; Final approval of the version to be published; Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. Renally Bezerra Wanderley e Lima: Analysis and interpretation of data for the work; Drafting the work and revising it critically for important intellectual content; Final 13 Charamba et al. Braz J Oral Sci. 2024;23:e241390 approval of the version to be published; Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. Rosângela Marques Duarte: Substantial contributions to the conception and design of the work; Analysis and interpretation of data for the work; Revising the work criti- cally for important intellectual content; Final approval of the version to be published; Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investi- gated and resolved. Marcos Antônio Japiassú Resende Montes: Substantial contributions to the concep- tion and design of the work; Analysis and interpretation of data for the work; Revising the work critically for important intellectual content; Final approval of the version to be published; Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. André Ulisses Dantas Batista: Substantial contributions to the conception and design of the work; Analysis and interpretation of data for the work; Revising the work criti- cally for important intellectual content; Final approval of the version to be published; Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investi- gated and resolved. Ana Karina Maciel de Andrade: Substantial contributions to the conception and design of the work; Analysis and interpretation of data for the work; Drafting the work and revising it critically for important intellectual content; Final approval of the version to be published; Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropri- ately investigated and resolved. References 1. Pizzolotto L, Moraes RR. Resin Composites in Posterior Teeth: Clinical Performance and Direct Restorative Techniques. Dent J (Basel). 2022 Nov;10(12):222. doi: 10.3390/dj10120222. 2. Chandrasekhar V, Rudrapati L, Badami V, Tummala M. Incremental techniques in direct composite restoration. J Conserv Dent. 2017 Nov-Dec;20(6):386-91. doi: 10.4103/JCD.JCD_157_16. 3. Kaisarly D, El Gezawi M, Keßler A, Rösch P, Kunzelmann KH. 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