Influence of Root Canal Preparation on Formation of Dentinal Microcracks: A Systematic Review

Abstract

The effect of root canal preparation technique on microcrack initiation is a controversial issue. This systematic review aimed to assess the role of root canal preparation techniques with different kinematics (manual, rotary, reciprocating, adaptive, self-adjusting file) on microcrack initiation. In vitro and in situ studies comparing the influence of at least two different root canal preparation techniques on the initiation of dentin microcracks were searched in PubMed/MEDLINE and SCOPUS up to June 5, 2018 without language and period restriction. Two authors independently reviewed all identified titles and abstracts for eligibility. Tables were generated to summarize the included studies, and the included studies were assessed for bias. Fifty-four (n=54) articles met the eligibility criteria. The results were classified according to the method used for microcrack evaluation, and most studies that used micro-computed tomography showed no formation of new cracks after root canal preparation. In general, the instrumentation techniques induced microcrack formation when the methods were destructive, irrespective of kinematics. In relation to the apex region, when the preparation working length was set as the root canal length subtracted of 1 mm, the risk of microcrack initiation reduces. The majority of the included studies had low risk of bias for all assessed domains. Our results seem to indicate that the various root canal preparation techniques considered in this study will not cause damage to the dental structure when adequately employed and the proper methodology is applied.

Micro-computed tomography assessment of dentinal microcracks after the preparation of curved root canals with rotary and reciprocal systems

“…A recently published systematic review indicated that in all root canal preparation techniques, a proper working length (1 mm short of the apex) is required to prevent microcrack formation. 23 This was not the case in the studies by Li et al 18 and Bayram et al, 3 and might be the possible reason for the development of dentinal microcracks in their studies.…”

“…This finding is in agreement with the results of the majority of previous studies that used micro-CT for the assessment of microcrack formation after root canal instrumentation. 9,10,12,[19][20][21][22][23][24][25] A study conducted in 2014 used micro-CT for the first time and showed no cause-and-effect relationship between dentinal microcrack formation and root canal instrumentation. 10 After that, many micro-CT studies confirmed this finding.…”

The effectiveness of the supplementary use of the XP-endo Finisher on bacteria content reduction: a systematic review and meta-analysis

“…Regarding the analysis of bias, there are no well-defined criteria to assess the risk of bias in in-vitro studies, and the studies included in the present systematic review were analyzed by adapting prior criteria adopted in other reviews that evaluated in vitro studies [ 19 20 21 ]. Therefore, some methodological features with the potential to introduce some bias to the results were defined a priori.…”

“…The risk of bias of the included studies was assessed by using adapted criteria for systematic reviews of in vitro studies [ 19 20 21 ]. Therefore, the following criteria were analyzed: similarity of specimens, specimen randomization, accordance with manufacturers' directions, standardization of inoculum, and blinding of outcome assessment.…”

The Influence of Root Canal Preparation with ProTaper Next, WaveOne Gold, and Twisted Files on Dentine Crack Formation

“…Chronologically, as reciprocal instruments were introduced to the market, some research groups suggested their use may be more detrimental to root canal dentine than rotary files [9,10]. However, observations made later did not confirm this phenomenon, and the issue seems unresolved, as the values achieved by different, unrelated teams seem to be similar [11,12].…”