Influence of threaded intra-radicular retainer design on the formation of micro cracks in the

Abstract

The purpose of this research was to evaluate the formation of microcracks in the root during preparation of the thread for placement of threaded intra-radicular retainers
of the Screw Post and Flexi Post Systems, considering the differences in design between the two systems, and the force of the threading movement. The methodology used for evaluation was Optical Microscopy evaluation. Twenty-eigth mandibular human endodontically treated incisors were used, divided into 4 groups, two groups being for manual movement until resistance was encountered, and 2 for use of an implant dentistry torque meter calibrated to 10N. The images obtained after the cleavage of the specimens were observed by 2 blind evaluators, and demonstrated that there was no crack formation in the root during thread preparation for the two systems, both with manual movement and with movement calibrated at 10N. It was concluded that the use of both Flexi-Post and Screw-Post is safe as regards the formation of microcracks during thread preparation.