Journal of EndodonticsVolume 39, Issue 1 , Pages 129-132, January 2013
Abstract
Introduction
The aim of this study was to
compare the incidence of apical root cracks and dentinal detachments
after canal preparation with hand and rotary files at different
instrumentation lengths.
Methods
Two hundred forty
mandibular incisors were mounted in resin blocks with simulated
periodontal ligaments, and the apex was exposed. The root canals were
instrumented with rotary and hand files, namely K3, ProTaper, and
nickel-titanium Flex K files to the major apical foramen (AF), short AF,
or beyond AF. Digital images of the apical surface of every tooth were
taken during the apical enlargement at each file change. Development of
dentinal defects was determined by comparing these images with the
baseline image. Multinomial logistic regression test was performed to
identify influencing factors.
Results
Apical crack
developed in 1 of 80 teeth (1.3%) with hand files and 31 of 160 teeth
(19.4%) with rotary files. Apical dentinal detachment developed in 2 of
80 teeth (2.5%) with hand files and 35 of 160 teeth (21.9%) with rotary
files. Instrumentation with rotary files terminated 2 mm short of AF and
did not cause any cracks. Significantly less cracks and detachments
occurred when instrumentation with rotary files was terminated short of
AF, as compared with that terminated at or beyond AF (
P <
.05). The AF deviated from the anatomic apex in 128 of 240 teeth (53%).
Significantly more apical dentinal detachments appeared in teeth with a
deviated AF (
P = .033).
Conclusions
Rotary
instruments caused more dentinal defects than hand instruments;
instrumentation short of AF reduced the risk of dentinal defects.
Comments