Evaluation of the centreing ability of the ProTaper Universal™ rotary system in curved roots in comparison to Nitiflex™ files

Abstract

The aim of the present study was to assess the centreing ability of the ProTaper Universal rotary system in curved roots in comparison to Nitiflex files, by means of preoperative and postoperative imaging of a cross-section of the apical third. Twenty mesiobuccal canals of human first mandibular molars with a degree of curvature ranging from 35 degrees to 60 degrees were divided into two groups of 10 specimens each: group 1, ProTaper Universal rotary system; group 2 (control), Nitiflex files. All instruments produced morphological alterations. The Student's t-test and Kruskal-Wallis test showed that the differences were not statistically significant, except for the specimens instrumented by Nitiflex file #30. The ProTaper Universal showed the capacity for producing centered preparations in curved and thin root canals with low proportions of apical deviation.