Composite occlusal bite blocks bonded without liquid resin

Abstract

AIM: Liquid resin in bonding composite has been identified as a major irritant in human cell culture. However, liquid resin is assumed to play a critical role in composite adhesion to enamel by forming resin tags to mechanically interlock with acidetched enamel prisms. By bonding occlusal bite blocks to enamel surfaces without the use of liquid resin, mechanical interlocking between the liquid resin tags and acid-etched enamel prisms should not exist to enable the bite blocks to resist heavy functional occlusal forces. Survival analysis of a case series of composite bite blocks bonded without liquid resin will demonstrate if mechanical interlocking is critical in the mechanism of enamel adhesion. The aim of this study was to evaluate the role of mechanical interlocking in the mechanism of enamel adhesion of composite resin in vivo. SUBJECTS AND METHOD: Twenty-three patients had bilateral occlusal bite blocks bonded on the posterior teeth to raise the bite during fixed orthodontic therapy. Depending on the individual clinical situation and enamel quality, the choice of the occlusal surfaces of teeth for the bite blocks bonded without liquid resin included 55 and 65 (1 case), 17 and 27 (1 case), 16 and 26 (14 cases), 35 and 45 (1 case) and 36 and 46 (6 cases). The service durations of the occlusal bite blocks recorded were analyzed using the Kaplan Meier product limit method. RESULTS: Twenty-two of the 23 patients (95.7%) experienced no failure of the bilateral occlusal bite blocks. Forty-five of 46 (97.8%) occlusal bite blocks lasted up to the end of their intended treatment purposes. They remained on average for 27.8 months (range 1.5 to 29.0 months), and the only failure occurred at 1.5 month. The failed bite block was replaced to finish the treatment (additional 3.1 months). CONCLUSION: This clinical trial demonstrates that mechanical interlocking does not seem to have a critical role in the mechanism of enamel adhesion in vivo.