Effect of charcoal-based dentifrices on the surface integrity and gloss of lithium disilicate glass-ceramics.

Objectives: To evaluate the effects of commercially charcoal-based dentifrices on the surface roughness and gloss retention of glazed lithium disilicate glass-ceramics subjected to simulated toothbrushing.

Materials and methods: Seventy-two glazed lithium disilicate specimens (IPS e.max CAD) were randomly assigned to three dentifrice groups (n = 24): two charcoal-based (Carvvo (CVV), Curaprox Black is White (CBW)) and one conventional (Colgate Total 12 (C12)), the control. Toothbrushing simulations were performed for 5,000, 10,000, and 20,000 cycles. Roughness (Ra) and gloss (GU) were measured at baseline and after each cycle. Surface characterization was performed using three-dimensional profilometry and scanning electron microscopy (SEM), which also analyzed abrasive particles. Data were analyzed using two-way repeated measures ANOVA and Tukey's post-hoc test (α = 0.05).

Results: Roughness was affected only by dentifrice type (p = 0.004), with CVV producing higher mean values than C12, and CBW not differing from the others. Brushing cycle (p = 0.164) and interaction (p = 0.095) were non-significant. Gloss was affected by dentifrice (p < 0.001), brushing cycle (p < 0.001), and their interaction (p < 0.001). Charcoal-based dentifrices caused gloss reductions (CVV: 80.77GU baseline to 67.41GU at 20,000 cycles; CBW: 86.39GU baseline to 69.62GU at 20,000 cycles). In contrast, C12 increased gloss, reaching up to 95.97GU at 20,000 cycles.

Conclusions: Charcoal-based dentifrices significantly compromise the surface integrity of glazed lithium disilicate ceramics by increasing roughness and reducing gloss. Conventional dentifrices demonstrate no deleterious effect on ceramic surfaces and may even enhance gloss.

Clinical relevance: Routine use of charcoal-based dentifrices may accelerate surface wear and reduce optical properties of ceramic restorations, potentially compromising longevity and esthetic outcomes.