Objectives: This in situ/ex vivo study aimed to analyse the impact of possible MMP-inhibitors (chlorhexidine and green tea extract) on dentin wear induced by erosion or erosion plus abrasion.
Methods: Twelve volunteers took part in this cross-over and double-blind study performed in 4 phases of each 5 days. Bovine dentin samples were worn in palatal appliances and subjected to extraoral erosion (4 times/day, Coca-Cola, 5 min) or erosion plus abrasion (2 times/day, fluoride-free toothpaste and electrical toothbrush, 15s/sample). Immediately after each erosion, the appliances were reinserted in the mouth and the oral cavity was rinsed for 60s with: 250 ppm F solution (SnF(2)/AmF, pH 4.5, Meridol-Gaba, Switzerland), 0.12% chlorhexidine digluconate (0.06% chlorhexidine, pH 6.0, Periogard-Colgate, Brazil), 0.61% green tea extract solution (OM24, 100% Camellia Sinensis leaf extract, catechin concentration: 30+/-3%, pH 7.0, Omnimedica, Switzerland) or deionized water (pH 6.0, control). Dentin loss was assessed by profilometry (microm). The data were analysed by two-way repeated measures ANOVA and Bonferroni post hoc test.
Results: There was a significant difference between the conditions (EroxEro+Abr, p<0.001) and among the solutions (p<0.001). All solutions (F: 1.42+/-0.34; 1.73+/-0.50, chlorhexidine: 1.15+/-0.26; 1.59+/-0.32, green tea: 1.06+/-0.30; 1.54+/-0.55) significantly reduced the dentin wear when compared to control (2.00+/-0.55; 2.41+/-0.83) for both conditions. There were not significant differences among green tea extract, chlorhexidine and F solutions.
Conclusions: Thus, the possible MMP-inhibitors tested in this study seem to be a promising preventive measure to reduce dentin erosion-abrasion, but their mechanism of action needs to be investigated in further studies.