Resin Composite Wear by Charcoal Dentifrice at 6-Months Simulated Brushing

Objectives: The present study aimed to investigate the wear potential of charcoal toothpastes over resin composite.
Methods: Sixty maxillary and mandibular molars were embedded in epoxy resin (Epoxicure 2, Buehler). A 4x4x2mm preparation on the facial surface was performed and later restored with resin composite (Adhese Universal, Ivoclar; Tetric Evo-Ceram, Ivoclar). The resin composite surfaces were scanned with a laser microscope (VK-250, Keyence) at 20X with roughness values (Ra) recorded (baseline). Samples were divided in three groups (n=20) according to the toothpaste; control group with no toothpaste slurry (CG); charcoal toothpaste group (CT) (Hello Charcoal, Hello Products); regular toothpaste group (RT) (Crest Pro-Health, Procter & Gamble). Specimens were placed in a custom toothbrush simulator (MEV4T 10XY, Odeme) with a soft toothbrush (Indicator, Oral-B) applying 200 g-force to the specimen surface. Simulated toothbrushing was accomplished at 120 cycles per minute for a total of 5000 cycles, equivalent to six months of normal toothbrush use. Dentifrice slurry was prepared with deionized water (1-1). At the end of cyclic testing, the specimens were rinsed, dried, and scanned. Normality and variance were evaluated using the Shapiro-Wilk and Bartlett’s tests respectively. Kruskal-Wallis test with Dunn’s post hoc analysis were used to compare values between groups. Wilcoxon matched-pairs signed rank test was used for preoperative and postoperative comparison within each group. All analysis was accomplished at a 95% level of confidence.
Results: No statistically significant difference was observed between groups in the baseline (p=0.62). CT presented significantly greater Ra (p=0.03) when compared to CG and RT. When intragroup analysis was assessed, there were no significant differences within CG (p=0.58) and RT (p=0.59), while a significant difference (p=0.014) was identified in the CT group.
Conclusions: It could be concluded that the charcoal toothpaste increased the roughness of the resin composite.