In vitro evaluation of bond strength to primary tooth dentine and microleakage properties of silorane based composite resin

The aim of this in vitro study is to evaluate the microleakage properties and shear bond strength to primary and permanent tooth dentine of the low polymerization shrinkage silorane based composite resin and to compare the results with a methacrylate based composite resin.Shear bond strength test method was selected to evaluate the bond strength of the groups. Buccal dentine surfaces of primary and permanent molar teeth were used. For the test group silorane based composite resin and for the control group methacrylate based composite resin was used according to the manufacturer?s instructions. The composite resins were placed using 4 mm diameter, 5 mm height cylindrical plastic tubes. Shear force was applied to each specimen at a crosshead speed of 1mm/min until failure occurred. The surfaces of the broken samples were detected under stereomicroscope and were grouped as adhesive, cohesive and mix. Dye penetration method was selected for the microleakage test. Class V cavities were prepared on the buccal surfaces of primary and permanent molar teeth. The same materials and groups of the shear bond strength test method were used in the microleakage test. Thermal cycling was applied for 1000 times. After keeping them in a 0.5% methylene blue solution for 24 hours, teeth were cut along the center line in the bucco-lingual direction and the surfaces were examined under a stereomicroscope. Dye penetration levels were recorded in accordance with determined scores.Silorane based composite resin was showed lower shear bond strength for primary and permanent tooth dentine (p< 0.05). Primary tooth dentine were showed lower shear bond strengths for silorane based composite resin than permanent tooth dentine, whereas no significant difference was observed between primary and permanent tooth dentine for methacrylate based composite resin (p< 0.05). It was observed that most of the failures occurred in silorane based composite resin group, were adhesive type failures. According to the microleakage evaluation, teeth were restored with silorane based composite resin were showed least microleakage (p< 0.05). However, no different was found between primary and permanent teeth restored with the same composite resin (p< 0.05).