بررسي آزمايشگاهي مقاومت شكست ترميمهاي كامپوزيتي باند شده

RESISTANCE OF BONDED COMPOSITE RESTORATIONS ON FRACTURES OF ENDODONTICALLY TREATED TEETH

Introduction: This study was performed to evaluate the effect of dentine bonding agents and Glass Ionomer cement beneath composite restorations and its resistance on fractures of endodontically treated teeth. Material and Methods: Forty sound maxillary teeth were select ed; ten of them for positive control, and on the rest, RCT and MOD cavity preparations were done with standard methods. Then, the teeth were divided to four groups: l -Sound teeth for positive control. 2-Prepared without any restoration for negative control . 3-Prepared and restored with Vitrabond(3M, USA), Single bond(3M, USA) and Z100(3M, USA) resin composite. 4-Prepared and restored by Single bond and Z100 resin composite. Specimens were subjected to compressive load by Instron 8502 until fracture occurre d. Results: Group 1 showed the highest resistance to compressive forces followed by group 4,3&2 respectively. ANOVA, t test and Chi-square tests indicated significant difference between all the groups. Conclusion: Use of dentine bonding agents and resin composite increases resistance of endodontically treated teeth to fractures more than teeth restored with sandwich of glass ionomer cements, dentine bonding agents and resin composite.