To Observe The Effect Of Different Dental Filling Technologies On The Microleakage Under Confocal Laser Scanning Microscope

Objective: The purpose of this study to evaluate the different filling technologies impact on the materials microleakage under confocal laser scanning microscope, so as to supply scientific data for selecting optimal filling technologies in clinic.Methods: 40 healthy extraced young human premolares were used for this study. A box cavity preparation was performed on occlusal surface (4.0mm×3.0mm×2.0mm).The teeth were randomly assigned to two groups(A and B),twenty in each. A group was randomly divided to two subgroups A1 and A2. B group was randomly divided to two subgroups, B1 and B2. A group filled with silver amalgam,A1 group adopted BAR; A2 filled with silver amalgam directly. B group filled with composite resin, B1 adopted self-etching adhesive system; B2 adopted totaletching adhesive system. After dying, all the specimen were dipped in 37℃physiological saline for 1d and were thermal cycle for 500 times at the same time. After, the apical foramen of each specimen was covered with self-curing rising followed and two layers of nail varnish were applied to all surfaces of the teeth leaving 1.0 mm away from the cavity margins. All the teeth were immersed in 0.1%Rhodamine B alcohol solution for 24 hours at 37℃and washing by distilled water. Using a slow speed diamond disk with water coolant, producing approximately 1.5mm wide samples and polished the samples. Finally, Laser Scanning Confocal Microscope was used to visualize the depths of dye penetrated and quantitate the microleakage depth.Results: The dye penetrations were observed in each group. In the silver amalgam group, the microleakage depth of A1 group was 20.54±5.38μm and A2 was 35.71±9.97μm , A1 and A2 had significant difference(P<0.05). In the composite resin group , the microleakage depth of B1 group was 60.03±7.83μm and B2 group was 46.78±10.28μm,B1 and B2 also had significant difference(P<0.05).Conclusions:1.Using Bonded Amalgam Restorations caused less microleakage than filling silver amalgam directly .2.Total-etching adhesive system caused less microleakage than self- etching.