Fracture resistance of mollars with MOD cavities restored with different materials

Restoring teeth with second class cavities is a challenge in dentistry. Both the carious process and the preparation of the cavity for the dental restoration reduces the tooth resistance to the masticatory forces. It has been shown that modern aesthetic materials using an adhesive system improve the stress resistance of the restored teeth. There is a series of studies that attempted to determine the type of optimal material that would provide increased resistance to occlusal demands. In the present study we tried to determine the fracture resistance of molars with second class cavities restored with different categories of aesthetic materials. Thus, forty intact molars were divided into five groups of 8 teeth, MOD cavities were prepared and the teeth were restored with three types of materials: nanofilled composite, mycrohibrid composite and ormocer. The teeth of the first group were left unprepared, and those belonging to the second group were subjected to the preparation of MOD cavities but were not filled. Samples were subjected to compression using an Universal Loading Machine (Lloyd Instruments) and the value of the force they failed was recorded. Intact teeth showed the highest resistance to compression and those with MOD cavities prepared but not filled showed the smallest. Of the groups that benefited from restoration with filling material, the teeth restored with ormocer had the highest resistance, followed by those restored with nanofilled composite, and finally by those restored with mycrohibrid composite.