A randomized clinical trial of cusp-replacing resin composite restorations: efficiency and short-term effectiveness.

PURPOSE: This study aimed to assess the efficacy and short-term effectiveness of the morphology and function of direct and indirect cusp-replacing resin composite restorations. MATERIALS AND METHODS: In 94 patients, 106 cusp-replacing restorations for maxillary premolars were fabricated to restore Class II caries lesions with 1 cusp missing. Fifty-four direct (Clearfil AP-X) and 52 indirect (Estenia) resin composite restorations were placed following a strict protocol. The treatment technique and operator were assigned randomly. Treatment time was recorded for all restorations. One-month postoperative evaluation included assessment of postoperative sensitivity and presence of occlusal and proximal contacts. RESULTS: Treatment time for the indirect technique (68 +/- 17 min) was longer than for the direct technique (45 +/- 13 min). Regression analysis revealed that the restorative method, operator, and location of the preparation outline had a statistically significant effect on the total treatment time. Occlusal contacts were observed in 94% of the direct restorations and in 98% of the indirect restorations (chi-square, P>.05). Mesial proximal contacts were present in 98% of the direct and in 97% of the indirect restorations (chi-square, P > .05). Distal contacts were present in 100% of the restorations for both techniques. Postoperative sensitivity within 1 week posttreatment was reported for 11% of the direct restorations and for 13% of the indirect restorations, but decreased to 4% and 6%, respectively, after 1 month (chi-square, P > .05). CONCLUSION: The results of this study suggest that in the short term, both direct and indirect adhesive techniques are adequate to restore the morphology and function of premolars presenting with Class II caries lesions and a missing cusp.