Secondary caries adjacent to amalgam restorations lined with a fluoridateddentin desensitizer

Purpose: To determine the in vitro effect of a fluoridated dentin desensiti zer solution (DentinBloc) on (1) secondary caries formation, and (2) the in terfacial adaptation when used as a cavity liner before amalgam (Dispersall oy) placement. Materials and Methods: 24 macroscopically caries-free molars were selected. Class V cavity preparations on mesial and distal surfaces w ere placed along the cemento-enamel junction, providing an enamel margin an d a root surface margin. DentinBloc was applied prior to alloy restoration in the experimental group for 60 s (the excess was removed with cotton pell ets), while a copal cavity varnish (Copalite) was used before alloy restora tion in the control group. Polarized light evaluation was performed on long itudinal sections (24 caries risk sites for enamel and dentin margins in ea ch group). Alloy-tooth interfaces were evaluated by SEM. Results: Wall lesi ons were present in 100% of caries-risk sites for the control group, while 58% of enamel risk sites and 50% of root risk sites had wall lesions in the DentinBloc group. Surface lesion depth was reduced 13% at enamel margins a nd by 18% at root margins in the experimental group when compared to the co ntrol group. Relatively small interface gaps between the alloy and tooth su rfaces were seen in both groups, but these were less for the root surface m argins (2-5 mu m) than for the enamel margins (5-15 mu m).