ASSESSMENT OF CANAL WALLS AFTER BIOMECHANICAL PREPARATION OF ROOT CANALS INSTRUMENTED WITH PROTAPER UNIVERSAL™ ROTARY SYSTEM

OBJECTIVE: The aim of this study was to examine the instrumented walls of root canals prepared with the ProTaper Universal™ rotary system. MATERIAL AND METHODS: Twenty mesiobuccal canals of human first mandibular molars were divided into 2 groups of 10 specimens each and embedded in a muffle system. The root canals were transversely sectioned 3 mm short of the apex before preparation and remounted in their molds. All root canals were prepared with ProTaper Universal™ rotary system or with Nitiflex™ files. The pre and postoperative images of the apical thirds viewed with a stereoscopic magnifier (×45) were captured digitally for further analysis. Data were analyzed statistically by Fisher's exact test and Chi-square test at 5% significance level. RESULTS: The differences observed between the instrumented and the noninstrumented walls were not statistically significant (p<0.05). CONCLUSIONS: The Nitiflex™ files and the ProTaper Universal™ rotary system failed to instrument all the root canal walls.