Microleakage around a low-shrinkage composite cured with a high-performance light

To compare microleakage of Class V restorations filled with a novel low-shrinkage resin-based composite cured by a high intensity light and a combination of controls including a conventional composite cured by conventional and soft-start regimes. METHODS: Forty-two intact premolar and molar teeth were randomly assigned to seven groups and filled with a low-shrinkage composite or a conventional composite, bonded with one of two bonding materials (Excite or Prime&Bond NT) and cured with either a high intensity light, a soft-start regime or a conventional light regime. Cavities were cut in both the buccal and lingual aspects of each tooth with half of the preparation in enamel and half in dentin/cementum. The teeth were thermocycled and the restorations examined microscopically for leakage using Procion Brilliant Red as a marker. RESULTS: None of the groups showed microleakage at the enamel margins. All groups showed leakage at the gingival margins. At the gingival margins there was no significant difference between the low-shrinkage composite, bonded with the manufacturer's adhesive, and cured by high intensity regime, and the conventional composite bonded by the manufacture's adhesive and cured by one of two soft start regimes. Nor was there a significant difference between the low-shrinkage composite, bonded by the manufacturer's adhesive and cured by either the high intensity regime or one of two soft start regimes. The low-shrinkage material, bonded by the manufacturer's adhesive and cured by the high intensity regime showed significantly less microleakage than the conventional composite, bonded by the manufacturer's adhesive and cured with a conventional light source. CLINICAL SIGNIFICANCE: Gingival marginal microleakage is not prevented by the use of a low-shrinkage composite cured by a high intensity light. If time were an essential consideration, the low shrinkage composite cured by a high intensity regime may offer clinical advantages.