Mathew, MNair, EKPKrishnan, K2017-03-102017-03-10200128 ,1;68-7710.1046/j.1365-2842.2001.00609.xhttps://dspace.sctimst.ac.in/handle/123456789/9387The marginal leakage at the dentine/composite interface in Class II composite restorations subjected to thermal cycling has been effectively evaluated using the silver staining technique. The presence of a bonding agent at the dentine/composite interface is found to improve adhesion. Scanning electron and optical microscopic observations of sectioned specimens reveal that applying a second coat of bonding agent on the dentinal surface helps in reducing microleakage compared to a single coat application, in all three radiopaque composite/bonding agent systems studied (Z1001Single Bond, Spectrum TPH/Prime & Bond 2.1 and Chitra/Chitrabond 1.0). Thermal cycling during in vitro studies was found to provide a more appropriate representation of the adhesive behaviour of the composite in clinical situations.Dentistry, Oral Surgery & Medicine