Efficacy of Topical Strategies to Prevent the Onset of Root Caries Lesions, In vitro.

Preventive fluoride-based topical products, such as silver diamine fluoride (SDF) and others with chlorhexidine have been widely used as a strategy for preventing dental caries lesions, at all ages. Whether they are effective against root caries is less clear. Aim: To evaluate the efficacy of various dental products in preventing root caries lesions, using a biological model of root caries. Methodology: An experimental in vitro study was devised using a validated model with biofilms of Streptococcus mutans formed on bovine root dentin slabs. Slabs were divided into 5 experimental groups: (1) 1% chlorhexidine gel, (2) 22,600 ppm fluoride varnish, (3) 5000 ppm fluoride toothpaste, (4) 38% SDF and (5) negative control (0.9% NaCl). After the experimental phases, biofilms were detached from the dentin slabs to assess biomass and the number of viable cells (CFU). Demineralization of dentin slabs was evaluated by laser fluorescence and surface Knoop microhardness loss. Results: Dentin slabs treated with SDF did not significantly differ in surface microhardness loss compared to those treated with 1% chlorhexidine gel (p>0.05). However, both materials showed significantly lower surface demineralization than the rest of the groups. SDF had a higher impact on the properties of Streptococcus mutans biofilms. Conclusion: SDF seems more effective than other materials in preventing root caries lesions in a highly cariogenic environment.