Chlorhexidine and green tea extract reduce dentin erosion and abrasion in situ

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, 15 s/sample). Immediately after each erosion, the appliances were reinserted in the mouth and the oral cavity was rinsed for 60 s with: 250 ppm F solution (SnF2/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 (R), 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 (mu m). The data were analysed by two-way repeated measures ANOVA and Bonferroni post hoc test. Results: There was a significant difference between the conditions (Ero x Ero + 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. (C) 2009 Elsevier Ltd. All rights reserved.