Influence of three different sealants on root dentin demineralization in situ

PURPOSE: To evaluate in situ the onset of initial demineralization in human dentin pretreated either with two different dentin bonding agents or a desensitizer. METHODS: 28 freshly extracted human molars were included in this study. The root surfaces were thoroughly cleaned, thereby removing the cementum. From each tooth four root dentin specimens were prepared. The specimens were distributed among the following experimental groups: C: control group (untreated), S: Syntac Classic, X: Xeno III, and H: Hyposen. For each subject, one dentin specimen of each group was inserted into both buccal aspects of a bilateral intraoral mandibular appliance. The appliances were worn by 14 subjects for 5 weeks day and night. One side was brushed daily with fluoride-containing toothpaste (Aronal) (B). On the other side, plaque was allowed to grow (NB). Individual oral hygiene techniques were performed without any fluorides. During meals, the appliance was stored in 10% sucrose solution. After the in situ period, slabs (150 microm) were ground and studied using polarized light microscopy. RESULTS: For lesion depth, ANOVA revealed significant differences between brushed and unbrushed specimens. In the brushed groups, the following lesion depths were evaluated (mean values and standard deviation in microns): Group B-C: 74.1 (+/- 18.5), Group B-S: 27.6 (+/- 9.6); Group B-X: 28.7 (+/- 9.6), and Group B-H: 34.3 (+/- 20.6). The non-brushed specimens showed following lesion depths: Group NB-C: 101.7 (+/- 23.9), Group NB-S: 59.9 (+/- 13.1), Group NB-X: 52.5 (+/- 12.1), and Group NB-H: 72.9 (+/- 19.9). Compared to the non-brushed groups, lesion depths in the brushed group were significantly decreased (P < 0.05, Tukey's test). The reduction of lesion depths after application of the three agents was significant in both cases (brushed and non-brushed groups). Within the limitations of an in situ study it can be concluded that the demineralization of the root surface can be inhibited by application of dentin adhesives and desensitizers under different oral hygiene conditions.