Secondary caries adjacent to amalgam restorations lined with a fluoridated dentin desensitizer

To determine the in vitro effect of a fluoridated dentin desensitizer solution (DentinBloc) on (1) secondary caries formation, and (2) the interfacial adaptation when used as a cavity liner before amalgam (Dis-persalloy) placement.

24 macroscopically caries-free molars were selected. Class V cavity preparations on mesial and distal surfaces were placed along the cemento-enamel junction, providing an enamel margin and a root surface margin. DentinBloc was applied prior to alloy restoration in the experimental group for 60 s (the excess was removed with cotton pellets), while a copal cavity varnish (Copalite) was used before alloy restoration in the control group. Polarized light evaluation was performed on longitudinal sections (24 caries risk sites for enamel and dentin margins in each group). Alloy-tooth interfaces were evaluated by SEM.

Wall lesions 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 and by 18% at root margins in the experimental group when compared to the control group. Relatively small interface gaps between the alloy and tooth surfaces were seen in both groups, but these were less for the root surface margins (2-5 microns) than for the enamel margins (5-15 microns).