Evaluation of custom occlusal matrix technique for posterior light-cured composites

Posterior composite restorations are difficult to contour and polish due to their occlusal anatomy and opposing occlusion. Recently a new technique utilizing a clear custom occlusal matrix showed promise in reducing the chair time necessary to place posterior composite restorations. Sixty specially molded plastic mandibular right second molar teeth with a mesio-occlusal composite preparation were restored with a light-cured composite in a typodont, using either the custom occlusal matrix (experimental) or the standard technique (control) as taught at the University of Michigan School of Dentistry. The times necessary to complete the procedures were recorded. The teeth were evaluated in a blind manner by two evaluators using a modified Ryge criteria. The times to place and finish the control and experimental restorations were subjected to a t-test. The evaluations of surface smoothness, margin adaptation, occlusal anatomy, and axial form were compared using a Fisher exact test. The custom occlusal matrix significantly reduced placement and finishing time and improved surface smoothness of mesio-occlusal posterior composite restorations placed in vitro. Due to the time needed to construct the custom occlusal matrix, there was no significant difference in total mean time of the two procedures.