Bioactive varnishes as preventive and therapeutic agents for dentin under in vitro erosive challenges

Objectives: Erosive Tooth Wear (ETW) can cause dentin hypersensitivity and tissue loss. Besides the management of patient-related lifestyle, local strategies for prevention and control become essential to alleviate discomfort and avoid its progression. The aim of this study was to assess the ability of different biotechnologies on the impact of erosive scenarios through surface properties, as the surface microhardness (SM) and wettability (W). Methods: 120 molars (n = 10) were randomized into 3 groups based on dentin conditions: S: Sound, EE (extrinsic erosion): orange juice (3x/5 min/5 days - pH 3.2), and IE (intrinsic erosion): 0.01 M hydrochloric acid (4x/20 s/5 days - pH 2.3). Specimens were further subdivided by material: D: Duraphat (fluoride), G: Gluma Desensitizer (HEMA/glutaraldehyde), and B: PRG Barrier Coat (S-PRG). SM (KHN, 10 g/10 s/5x) and W were performed at three times: initial (I), after application (AA) and final (F). Data were subjected to normality and three-way repeated measures ANOVA tests (p < 0.05). Results: For SM, EE determined more aggressive changes even no differences were detected at final time, while the materials performed similarly. Regarding W, B and G reached greater values respectively after EE and IE conditions. No significant differences were seen among groups at final time. Conclusions: Surface properties are altered by different erosive challenges, while the varnishes were able to prevent/control the erosive effect distinctively. Clinical significance: Resin-based varnishes consisted by bioactive agents are able to minimize the erosive alteration on dentin surface.