Abstract
BackgroundTo evaluate the incidence of dentinal microcracks formation after root canal shaping procedures with HyFlex EDM and Vortex Blue rotary systems comparing with that of hand instrumentation using micro-computed tomography.Material and MethodsMandibular first molar teeth (n=60) having 50 to 200mesial root curvature were scanned using high resolution micro-CT imaging before root canal preparation to identify the presence of dentinal defects. Post-instrumentation cross-sectional images were taken and increased number and type of root defects were assessed and recorded. The data was statistically analysed by using chi-square test and McNemar’s test at a significance level of 5%.ResultsHyFlex EDM has shown greater increase in post instrumentation dentinal defects. Both rotary systems exhibited increased dentinal defects formation at coronal, middle regions which is statistically significant (P=0.042) when compared to apical region.ConclusionsHyFlex EDM has shown greater increase in post instrumentation dentinal defects followed by Vortex Blue rotary system and hand instrumentation resulted minimal defects. Key words:Craze lines, dentinal microcracks, micro–computed tomography, nickel-titanium files, root canal preparation.
Highlights
Successful endodontic treatment requires predictably shaped root canals to facilitate three dimensional obturation
Root canal shaping procedures and rotary instrumentation have been claimed as potential causes to induce formation of root dentinal cracks which can be extended as vertical root fracture(VRF) under functional load [2,3]
The percentage of pre-instrumentation dentinal defects observed in all the groups were ranged between 15% to 22% (Table 1)
Summary
Successful endodontic treatment requires predictably shaped root canals to facilitate three dimensional obturation. The Vortex Blue rotary system (DenTsply Tulsa Dental speciality, USA) uses a new proprietary method during NiTi wire processing and produces a distinctive “blue colour” titanium oxide surface layer These instruments produced by complex heating and cooling procedures, exhibit greater fatigue resistance and improved flexibility with controlled shape memory [9]. Most of the previous studies reported that instrumentation with hand files produced no or minimal dentinal defects [2,10,11], but one recent study claimed that manual instrumentation caused more dentinal defects than protaper rotary system [12] Because of these inconsistent reports about their biomechanical impact on root dentin, the objective of the study was to evaluate and compare the incidence of dentinal microcracks formation in moderately curved root canals, after performing shaping procedures with HyFlex EDM or Vortex Blue systems comparing with that of hand NiTi instrumentation, using micro-computed tomography. Conclusions: HyFlex EDM has shown greater increase in post instrumentation dentinal defects followed by Vortex Blue rotary system and hand instrumentation resulted minimal defects
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