Clinical Evaluation of Bioactive Injectable Resin Composite in Posterior Restorations

Statement of the problem: Marginal defects of composite fillings are often thought to be caused by poor adaptation of the restorative material to the cavity wall. To avoid these defects, particularly in posterior teeth, the use of flowable composites has been advocated because of their ability to 'wet' and adapt well to cavity margins and walls. However, flowable composites have a lower filler content and usually weaker mechanical properties than conventional composites. The continued development of resin composites has led to formulations designed to further simplify the filling procedure, provide better mechanical properties, reduce the effect of polymerization shrinkage stresses and improve aesthetics. Recently, a new type of highly filled flowable composite has been developed. It is characterized by its high viscosity and is claimed to have improved mechanical properties not dissimilar from conventional composite restorative materials. This composite contains nano-sized filler particles, and due to its consistency, the material has been referred to as an 'injectable composite'. Rationale for carrying out the trial: The rationale of this study is to evaluate the mechanical performance of injectable composite resin against nanohybrid composites, because of its easy handling, time-saving, better margin adaptation, and the gain of extra mechanical properties at the same time.