EVALUATION FOR CRACKS ASSOCIATED WITH ULTRASONIC ROOT-END PREPARATIONOF GUTTA-PERCHA FILLED CANALS

Many clinicians use ultrasonics for root-end preparations. The purpose of this study was to evaluate resected root-end surfaces of bilateral ly matched human teeth for cracks before and after ultrasonic root-end preparation. Twenty matched pairs of extracted single rooted teeth we re divided into two experimental groups. In group 1, root-end resectio n was performed on uninstrumented teeth. in group 2, root-end resectio n was performed after the canals were instrumented and filled with gut ta-percha. All teeth in both groups received root-end preparations usi ng ultrasonic instrumentation at low power. Two examiners evaluated th e root-ends after root-end resection and again after root-end preparat ion using zoom magnification of 20x to 63x. The number, types, and loc ation of cracks were mapped. There were no significant differences whe n gutta-percha filled roots were compared to uninstrumented roots with regard to the number or type of cracks after root-end resection or ro ot-end preparation. In addition, there were no significant differences in the number or type of cracks following root resection and ultrason ic root-end preparation when compared to teeth with root resection alo ne.