Evaluation of the working length after rotary instrumentation

Abstract

The aim of this study was to analyze the working length after rotary instrumentation in upper molars. Forty-two upper molars were used, which were shaped by crown down technique using Protaper rotary system. The working length was performed after cervical and medium thirds shaping, and after apical shaping, the working length was evaluated visually again by a gutta percha master cone. The results showed that 23% of the molars do not have correct working length, principally the palatal root canal. Thus, it can conclude that rotary instrumentation can result on teeth shaped incorrectly, and morphologic position of root canal can influence in the final result of working length.