Abstract
Introduction
The aim of this study was to evaluate the effects of large apical preparations in
the danger zones of the mesial root canals of mandibular molars instrumented with
the Mtwo and Reciproc systems (VDW, Munich, Germany) until reaching apical diameters
of 0.25 and 0.40 mm.
Methods
Twelve mandibular molars, the mesial roots of which presented distinct foramens and
similar anatomies, were selected using micro–computed tomographic scanning. Mtwo and
Reciproc instruments were used to shape the mesiobuccal or mesiolingual canals. The
mesial canals were scanned before and after the use of 0.25- and 0.40-mm Mtwo and
Reciproc instruments. The analyzed parameters included the root canal volume and remaining
dentin thickness at 5 different levels. The obtained data were subjected to paired
analysis of variance and Tukey or Friedman and Dunn tests for intragroup analysis
and the Mann-Whitney U test for comparison between the mesial and distal walls.
Results
There were no significant differences between the mesial and distal dentin thickness
for the points analyzed with both instrumentation techniques (P > .05). The volumetric analysis revealed a significant difference (P < .05) among the initial volume and after the use of the 0.25- and 0.40-mm instruments
for both systems. The use of the 0.40-mm instrument increased the root canal volume
in comparison to the 0.25-mm instrument (P < .05).
Conclusions
Both systems performed similarly for the preparation of curved root canals with separate
apical foramens. The increase of the root canal preparation with the 0.40-mm instrument
significantly increased the root canal volume at the apical third without significantly
reducing the dentin thickness in the danger zone for both instrument systems.
Key Words
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Article info
Publication history
Published online: August 12, 2014
Identification
Copyright
© 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.
