A comparison of Profile, Hero 642, and K3 instrumentation systems in teeth using digital imaging analysis

Objective. To evaluate the changes in cross-sectional area morphology of curved canals after instrumentation with Profile(R), Hero 642(R), and K3(R) using digital imaging analysis. Study design. Thirty mesial mandibular curved canals were used (25-40degrees). The molars were embedded in resin and the roots were sectioned transversely at three levels: apical, middle, and coronal. The canals were randomly distributed into 3 groups for instrumentation using Profile .04 and .06, Hero 642, and K3. The pre- and postinstrumentation sections were digitized and areas corresponding to the canals were measured with image-processing software. Results. Hero eliminated significantly more dentine than K3 and Profile in all 3 sections (P < .01, ANOVA test), with no differences observed between the latter 2 systems (P > .05, Student-Newman-Keuls test). All 3 systems yielded a rounded canal morphology in the coronal, middle, and apical thirds. Conclusion. Hero rotary instruments produced more changes in cross-sectional area of the root canal.