Biomimetic and protective effects of bioactive toothpastes on eroded enamel surfaces

This study aimed to evaluate the effectiveness of bioactive toothpastes in remineralizing eroded enamel surfaces in vitro. Bovine enamel blocks (n = 48) were obtained and classified into untreated, demineralized, and treated areas. Specimens were randomly classified into six groups (n = 8 each): fluoride-free toothpaste (NCT), Colgate Total 12 (PCT), Sensodyne Repair and Protect (SRP), Sensodyne Pronamel (SPE), Regenerador + Sensitive (RGS), and RGS/calcium booster (RCB). The specimens were subjected to erosive pH cycling for 5 days for 4 times/day (90 s) and treated with toothpaste slurries (1:3) for 1 min. The Vickers hardness (50 g/10 s) and percentage surface hardness recovery (%SMHR) were calculated. Furthermore, the topography and roughness (Ra) of the enamel surface were evaluated using a 3D non-contact optical profilometer, along with the tooth surface loss (TSL). Data were statistically analyzed using analysis of variance or Tukey's test (significance: 5%). The %SMHR of the SRP and NCT groups were significantly lower than those of the other groups (p < 0.05). Ra was higher when the eroded area was treated with SRP and SPE (p < 0.05). Treatment with RGS, PCT, and SPE favored the recovery of the enamel surface compared with the NCT group (p < 0.05). The best TSL results were obtained with treatment with RGS, followed by PCT and SPE (p < 0.05). The RCB group showed statistically equivalent results for surface hardness recovery and TSL (p > 0.05). Conclusively, PCT and RGS toothpastes were more effective in remineralizing the enamel surface.