Protective Impact of the Salivary Pellicle on Dental Erosion

Objective: This study aimed to investigate and compare the protective impact of the in situ formed salivary pellicle on enamel and dentine erosion caused by different acids at pH 2.6.

Methods: Bovine enamel and dentine samples were exposed for 120 min in the oral cavity of ten healthy volunteers. Subsequently, enamel and dentine pellicle-covered specimens were extraorally immersed in either 1 ml hydrochloric, citric or phosphoric acid (pH: 2.6, 60 s, each acid: n = 30 samples). Pellicle-free samples (each acid: n = 10) served as controls. Calcium release into the acid was determined by atomic absorption spectroscopy. The data were analysed by two-way ANOVA and Tukey`s test (p<0.05).

Results: Pellicle-covered samples showed significantly less calcium loss compared to pellicle-free samples in all acid groups. The overall pellicle protection (% reduction of calcium loss) was significantly better for enamel (mean ± SD: 60.9% ± 5.3) than for dentine samples (mean ± SD: 30.5% ± 5.0), but revealed no differences among the acids.

Conclusion: The in situ pellicle is effective to reduce enamel and dentine erosion, but the protection is approximately twofold better for enamel than for dentine. However, at pH 2.6, the protective capability of the pellicle is not dependent upon the acid applied.