No abstract

No abstract

Objectives: The aim of this study was to evaluate six files on the pericervical dentin (PCD) and the smallest dentin thickness zones (SDTZ) in mesial root canals of mandibular molars. Materials and Methods: Sixty mesial roots with 2 canals were scanned before and after instrumentation with WaveOne Gold (WG), Reciproc Blue (RB), TRUShape (TS), XP-endo Shaper (XP), iRace (IR), and TruNatomy (TN). Surface, volume, structure thickness, SMI, and centroids were evaluated at the PCD, and the changes in the SDTZ were quantified. The data obtained werecompared using Wilcoxon and ANOVA with a 5% significance level. Results: XP and TN were similar in all the parameters (P >.05) at the PCD, but TN showed significant differences from WG, RB, TS, and IR (P <.05), while XP showed significant differences from WG (P <.05) in volume, surface, and structure thickness. Regarding the changes in the SDTZ, the amount of dentin removed was similar between the groups in both canals at the middle 1/3, at the cervical 1/3 for MB canals, and in ML canals for RB, TS, XP, IR, and TN (P>.05). The action of WG was significantly different from that of XP and TN in the cervical 1/3 of the ML canal (P <.05). Conclusions: XP and TN maintained better the anatomy, with minor changes at the PCD and SDTZ, while WG produced the largest changes. Centering at the PCD was maintained with all the files, and their performances were safe without risk of perforation. Clinical Relevance: The choice of endodontic files is a relevant factor in the conservative performance of root canal treatments. Trial Registration: No clinical trials were indicated in this study

This study aimed to determine the incidence of dentinal microcracks after instrumenting the root canals of maxillary premolars using two novel rotary instrumentation systems. Micro-computed tomography (microCT) scans and images generated by sectioning and observation with a stereomicroscope were used to assess the specimens. Twenty-two freshly extracted maxillary premolars were collected and the specimens were divided into two groups of eleven. The tested radicular shaping systems were XP-Endo shaper and TRUShape (i.e., single file). The specimens were scanned with microCT pre- and post-instrumentation, and the newly formed microcracks were detected. The post-instrumentation scans were also compared with images obtained by sectioning method and stereomicroscope inspection, comparing the incidence of microcracks in either microCT scans or images. The results identified an overall incidence of 0.49% of newly formed microcracks, with no statistically significant differences (p = 0.689) between the shaping systems (0.11% for TRUShape and 0.87% for XP-Endo shaper). There were statistically significant differences (p < 0.001) between the microcracks incidence in microCT scans and the sectioning method (16.6% more for the latter). In conclusion, the results show that neither TRUShape nor XP-Endo shaper created dentinal microcracks during root canal instrumentation. The sectioning method with stereomicroscope evaluation overestimates the presence of microcracks with a statistically significant difference compared to microCT scans.