Thickness of acquired salivary pellicle as a determinant of the sites of dental erosion

Dental erosion shows a typical distribution pattern within the dental arche s. Tooth protection from erosion by salivary pellicle has been shown in vit ro, but the hypothesis that pellicle may differ quantitatively at sites of erosion has not been investigated. This study aimed to determine the thickn ess of acquired salivary pellicle within the dental arches, investigate the possible relationship of this thickness to the distribution and severity o f erosion within the arches, and confirm the protective effect of pellicle against dental erosion. Eight enamel blocks were produced from each of 5 bo vine incisors assigned to five volunteers. Each block was further cut into 2 slabs, producing control and experimental slabs. Pellicle developed on ex perimental slabs located on 8 intra-oral sites after 1 hr of exposure was s tained by "sheep anti-human IgGAM-FITC". Slabs were then visualized, and pe llicle thickness measured, by confocal laser scanning microscopy. Eroded en amel lesions were produced in experimental and control slabs by means of pu re orange juice. The degree of erosion was quantified by transverse microra diography. Pellicle thickness varied significantly within the dental arches and among individuals. An inverse relationship (r = -0.96, p < 0.001) was observed between the degree of erosion and pellicle thickness. Significant differences in erosion were observed between slabs with and those without p ellicle. This study has shown that the thickness of acquired salivary pelli cle varies within the dental arches, which may be responsible for the site- specificity of dental erosion, and that pellicle does protect the teeth fro m erosion.