Abstract
Introduction
The present study aimed to describe an in vitro study model to investigate root surface strain (RSS) and its correlation with the
initiation/propagation of microcracks during different endodontic procedures.
Methods
Four lower human incisors extracted microcrack free were selected by micro–computed
tomographic imaging. Two strain gauges were bonded to the root surface of each incisor.
Then, the teeth were prepared to reproduce the periodontal ligament artificially.
The gauges were attached to a data acquisition system. The RSS was recorded during
the entire endodontic procedure, which consisted of accessing the endodontic cavity,
cleaning, shaping preparation with an Mtwo rotary system (VDW, Munich, Germany), and
filling with a standardized technique. Each incisor was submitted to a different retreatment
protocol and supplementary cleaning method as follows: (1) Reciproc (RC, VDW) + Flatsonic
(FS; Helse, Santa Rosa de Viterbo, Brazil), (2) RC + XP-endo Finisher (XPF; FKG Dentaire,
La Chaux-de-Fonds, Switzerland), (3) Mtwo retreatment (MR) + FS, and (4) MR + XPF.
Finally, the teeth were rescanned to establish the postoperative microcrack formation
by 2 well-trained and blinded examiners.
Results
The maximum and minimum RSS values were −120 and 510 microstrains, respectively, for
all of the files. RC showed the highest RSS values during endodontic retreatment compared
with MR. FS demonstrated a higher variation between the minimum and maximum RSS than
XPF. No microcracks were observed in the specimens.
Conclusions
This preliminary study proposed an experimental model that would combine 2 methods
to evaluate the effects of endodontic systems on dentin. Although strain gauges would
provide data on the stresses created, the pre- and postoperative evaluation of micro−computed
tomographic images would enable microcrack formation to be determined.
Key Words
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Article info
Publication history
Published online: April 22, 2021
Identification
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© 2021 American Association of Endodontists.
