Influence of the digestive enzymes trypsin and pepsin in vitro on the progression of erosion in dentine

Objectives: In patients with eating disorders, gastric and pancreatic enzymes could possibly reach the oral cavity during vomiting and could perhaps degrade the organic matrix of eroded dentine. This in vitro study sought to investigate whether pepsin, trypsin or the combination of both, have an influence on erosive mineral loss in dentine and whether they are able to degrade the organic matrix. Methods: Sixty-four human dentine specimens were prepared and randomly divided into four groups. Specimens were cyclically de- and remineralised for six days. Demineralisation was performed with an HCl-solution (6x 5 min daily, pH 1.6) in groups 1 and 3; in groups 2 and 4 the demineralisation solution additionally contained pepsin (750 mu g/ml). After demineralisation, specimens of groups 3 and 4 were treated with a trypsin solution (6x 10 min daily, 2000 BAEE/ml). After each day, mineral content (mu m) was determined microradio-graphically, and the matrix degradation was determined by hydroxyproline analysis. Results: After six days, treatment with pepsin (group 2) or trypsin (group 3) had no significant influence on mineral loss. The combined impact of pepsin and trypsin led to significantly higher mineral loss (group 4: 202.5 +/- 37.4) compared to all other groups (group 1: 139.1 +/- 29.5, p <= 0.001; group 2: 108.8 +/- 34.7, p <= 0.001; group 3: 157.8 +/- 37.2, p <= 0.05). Hydroxyproline was found in all pepsin-solutions but in no trypsin- or HCl-solutions. Conclusion: The combined impact of pepsin and trypsin intensified dentine erosion progression in vitro. This could be one reason for the fast proceeding of dental erosion in patients with chronic vomiting. (C) 2010 Elsevier Ltd. All rights reserved.