Methods: Nine desensitizers, Shield Force (SF), G-Guard (GG), MS Coat (MS), Gluma Desensitizer (GD), Super Seal (SS), Sumart Protect (SP), NanoSeal NS), VivaSense (VS), and Clinpro XT Vernish (CL) were used. The specimens were prepared by cutting dentin of bovine madibular teeth into blocks (4x4x1-mm), and wet ground with #2,000-grid SiC paper to expose dentin surface. Then specimens were placed in an ultrasonocator filled with distilled water for 30 min to remove any debris including smear plugs. The desensitizing agents were applied on the dentin surfaces according to each manufacturer’s instruction. Specimens were dehydrated and coated with a thin film of gold, then observed using SEM at an accelerating voltage of 10 kV. The treated dentin surfaces were scanned and their micromorphology was evaluated for each desensitizer (n=3). Additionally, the presence of any dentinal surface alteration, precipitation, or debris was noted and described. The degree of partially and/or fully occluded tubules was calculated for each representative micrograph. Statistical analysis was accomplished (ANOVA and Tukey's test). The surfaces of the worn specimens were observed by laser scanning electron microscopy.
Results: The desensitizing agents produced occlusion of the dentinal tubules. However, the appearance of the precipitates, the level of coverage, and the degree of dentinal occlusion varied among the tested products. For GG and CL, dentin surfaces were totally covered and no dentinal tubules evident. SF, MS, GD, SS, and NS were found to have significantly higher percentages of partially or fully occluded tubules (81.9 to 97.8 %) than did SP and VS (33.0 to 41.9 %).
Conclusions: Based on the results of this study, occlusion and/or narrowing of the open dentinal tubules have been successfully achieved with desensitizers used.