The effect of mouthwashes containing biguanides on the progression of erosion in dentin

Background: Dental erosion is caused by frequent exposure to acids without the involvement of microorganism. This study analyzed the effect of biguanides (polyhexamethylene biguanide - PHMB and chlorhexidine - CHX) on dentin erosion due to their possible influence on the enzymatic degradation of the demineralized organic matrix. Method: Sixty bovine dentin specimens were prepared. On both sides of their surface, nail varnish was applied to maintain the reference surfaces for the determination of dentin loss. Samples were cyclically de-and remineralized for 6 days. Demineralization was performed with a 0.87 M citric acid solution (6x5 min daily). Thereafter, samples were treated with distilled water (negative control), 0.12% CHX (positive control), 0.07% PHMB, Sanifill Perio Premium (TM) (0.07% PHMB plus 0.05% NaF), or F solution (0.05% NaF) for 1 min and then subjected to enzymatic challenge for 10 min using a bacterial collagenase (Clostridium hystoliticum, 100 mu g/ml). Dentin loss was assessed using profilometry (mu m) daily. Data were analyzed using 2-way repeated measures-ANOVA and Bonferroni's test (p < 0.05). Results: Dentin loss progressed significantly for all groups during the 6 days. After the 3rd day, Sanifill Premium T, CHX, and PHMB significantly reduced dentin erosion compared to control. On the 6th day, the lowest mean (+/- SD) dentin loss was observed for Sanifill Perio Premium (TM) (94.4 +/- 3.9 mu m). PHMB and CHX led to intermediate dentin loss (129.9 +/- 41.2 and 135.3 +/- 33.5 mu m, respectively) that was significantly lower than those found for negative control (168.2 +/- 6.2 mu m). F (157.4 +/- 6.1 mu m) did not significantly differ from negative control. Conclusions: Sanifill Perio Premium (TM) mouthwash has a good potential to reduce dentin loss, which might be associated with the presence of PHMB.