Effect of the lingual margin configuration on the fracture strength of class IV resin based composite restorations under static loading

Dentistry includes restoring teeth for both esthetics, and function. In cases of upper teeth chipping, the dentist offers different treatment options including the use of resin material that is bonded to the remaining tooth structure. In order to improve the retention of the material, a tooth preparation is required, including smoothing margins and beveling the edges. Little is known about the longevity of these restorations related to the different bevel preparations. This study compared the fracture strength among the four types of bevels that retained the resin composites on upper anterior teeth. One hundred teeth were selected and then divided into four experimental groups (twenty-five teeth per group). Teeth were subject to thermocycling and static forces until they broke. Fracture strength and failure mode were recorded and compared. There was no difference in fracture strength and failure mode among the four designs for bevels. This study concludes that the proposed margin configurations to restore upper human incisors with resin did not affect the fracture strength.