INTRODUCTION: The aim of this study was to assess the occurrence of apical root transportation after the use of ProTaper Universal rotary files sizes 3 (F3) and 4 (F4). METHODS: Instruments were worked to the apex of the original canal, always by the same operator. Digital subtraction radiography images were produced in buccolingual and mesiodistal projections. A total of 25 radiographs were taken from root canals of human maxillary first molars with curvatures varying from 23-31 degrees. Quantitative data were analyzed by intraclass correlation coefficient and Wilcoxon nonparametric test (P = .05). RESULTS: Buccolingual images revealed a significantly higher degree of apical transportation associated with F4 instruments when compared with F3 instruments in relation to the original canal (Wilcoxon test, P = .007). No significant difference was observed in mesiodistal images (P = .492). CONCLUSIONS: F3 instruments should be used with care in curved canals, and F4 instruments should be avoided in apical third preparation of curved canals. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.
INTRODUCTION: The aim of this study was to assess the occurrence of apical root transportation after the use of ProTaper Universal rotary files sizes 3 (F3) and 4 (F4). METHODS: Instruments were worked to the apex of the original canal, always by the same operator. Digital subtraction radiography images were produced in buccolingual and mesiodistal projections. A total of 25 radiographs were taken from root canals of human maxillary first molars with curvatures varying from 23-31 degrees. Quantitative data were analyzed by intraclass correlation coefficient and Wilcoxon nonparametric test (P = .05). RESULTS: Buccolingual images revealed a significantly higher degree of apical transportation associated with F4 instruments when compared with F3 instruments in relation to the original canal (Wilcoxon test, P = .007). No significant difference was observed in mesiodistal images (P = .492). CONCLUSIONS: F3 instruments should be used with care in curved canals, and F4 instruments should be avoided in apical third preparation of curved canals. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.