Comparison of postoperative sensitivity of Bulk Fill composite using a two step technique with incrementally layered Nanocomposite in class 1 cavities and selective etch method: A Randomized Controlled Single Blind Trial

Restorative dentistry deals with the treatment of tooth defects and restores the function without compromising the biology. Poor adaptation can lead to postoperative sensitivity and failure of restoration. There are problems associated with using resin composite in posterior restorations, most important of which is shrinkage that occurs on setting, and causes postoperative sensitivity. Incremental filling technique reduces polymerization shrinkage by reducing the C-factor, but it has some drawbacks, like incorporation of voids between layers or contamination. These drawbacks have led some manufacturers to introduce composite resins for bulk filling techniques.  The bulk fill composite resins have low volumetric shrinkage, but studies have reported that placement of thick increments may increase the stress at the adhesive interface, which may increase postoperative sensitivity. Studies have however reported that the filling technique has no influence on polymerization shrinkage at adhesive interface. Despite the presence of various placement techniques and developments in the technology of resin composites clinical failures of composite restorations are still present. To the best of our knowledge, incidence of postoperative sensitivity using 3M Filtek Z350XT Nanofill composite and 3M Filtek Bulk fill composite has not been evaluated yet.  Hence this study is designed to compare and evaluate the postoperative sensitivity of Nanocomposite [3M Z350XT] using incremental layering technique and Bulk fill composite [3M Bulk fill] using a 2 step technique in class 1 cavities.