Fatigue resistance of teeth restored with cuspal-coverage composite restorations.

摘要: PURPOSE: This study assessed the influence of palatal cuspal coverage on in vitro fatigue resistance and failure mode Class II resin composite restorations including replacement buccal cusp premolars. MATERIALS AND METHODS: A master model was made a maxillary premolar with an MOD amalgam cavity simulated fracture from isthmus floor to CEJ. Using copy-milling machine, this preparation copied 20 extracted human premolars (group A). Subsequently, reduced by 1.5 mm; modified additional B). Direct were all teeth. Cyclic load (5 Hz) applied, starting 200 N (10,000 cycles), followed stages 400, 600, 800, 1,000 at maximum 50,000 cycles each. Samples loaded until or 210,000 cycles. RESULTS: Of restored group A, 20% withstood loading cycles; B, figure 55%. In 19% fractures ended below CEJ; 78% did. CONCLUSION: Palatal increased However, led more dramatic failures that restoration virtually impossible. suggests caution lowering remaining cusps for these adhesive clinical situation.