Micro-Computed Tomographic Evaluation of Shaping Ability and Dentinal Microcracks Formation After Using New Heat-Treated Nickel-Titanium Systems
Introduction: This ex vivo study aims to evaluate the shaping ability and dentine microcracks formation after using four different heat-treated files, EdgeTaper PlatinumTM, ProTaper GoldTM, Reciproc® Blue, and EdgeOne FireTM Files.
Methods: Forty extracted mandibular premolars were randomly selected. Samples were decoronated at 17mm from the apex with water cooling. Bruker© Skyscanner scanned the canal before and after instrumentation.
For each group (DataViewer program version 126.96.36.199, Bruker©micro-CT), the manufacturer's evaluation software calculated the percentage rate and morphometric measurements of the percentage of walls untreated.
Results: 65% continuous and 60% reciprocating files showed Type II defect in the apical third. The reciprocating motion files (Reciproc®Blue and EdgeOne FireTM) produced significantly fewer dentin microcracks than continuous motion files (E.T.P and PTG). In addition, Reciproc®Blue shows more removal of tooth structure than other files. Statistically, no significant difference detected when comparing all systems together regarding shaping ability, pre-shaping (p=0.427), after shaping (p=0.865), and dentin microcracks at coronal 3rd, middle third, and apical third (all p>0.05), thus proving the null hypothesis.
Conclusions: All the newer NiTi rotary instrumentation systems studied resulted in dentine damage in varying degrees and dentinal cracks resulting from the preparation procedures.