Dental composite restorative materials undergo shrinkage during their placement. When they are light-cured in a confined setting, the shrinkage they undergo generates stress at the bonded interface with the surrounding tooth structure. Often this stress is high enough to break the adhesive interface, causing a gap that leads to marginal staining, sensitivity and recurrent decay. This project will explore an alternative type of photo-initiator that can significantly reduce shrinkage stress. The new compound will be custom synthesized and its ability to initiate polymerization on a par with typical photo-initiator will be verified in a model composite using FTIR analysis. The polymerization stress of the model composite will be measured and compared with a composite containing typical photo-initiator. The in vitro wear resistance and fracture toughness of the composites containing novel initiator will be compared to composites containing typical initiator to ensure their clinical viability. Microleakage in class V restorations will be simulated in extracted human molars for the novel composites to demonstrate their superior marginal seal compared to a control composite. A composite that produces low polymerization stress would alleviate a long-standing problem in dentistry, with potential applications to other industries such as automobile and electronics manufacturing. ? ?
