Protective Coating and Marginal Integrity of Class II Restorations

In the past, amalgam and direct gold fillings were the options for dental practitioners to use as posterior restorative material. The demand for better esthetics, possible mercury toxicity from amalgam has changed the perspective. Improvements in resin composite materials have made composite restorations a popular alternative to amalgam restorations in posterior teeth. How ever there are problems associated with using resin composite restorations including, marginal leakage, postoperative sensitivity and secondary caries. It is believed that the gap formed because of polymerization shrinkage leads to ingress of cariogenic bacteria, leading to secondary caries. Microleakage can be reduced by several factors as, using low shrinkage monomer, low intensity curing, incremental technique, introducing a low modulus material at the resin-dentin interface which will penetrate contiguously to envelop exposed collagen fibrils & to encapsulate the hydroxyapatite of underlying dentin.