Comparison of microcomputed tomography, cone beam tomography, stereomicroscopy, and scanning electron microscopy techniques for detection of microcracks on root dentin and effect of different apical sizes on microcrack formation

Abstract

The aim of the study was to compare different imaging methods in the diagnosis of microcracks on root dentin and to evaluate the frequency of dentinal microcracks observed after root canal preparation using the ProTaper Universal (PTU) system of different sizes. A total of 30 mandibular molars' mesial roots were scanned with microcomputed tomography (micro‐CT) and cone beam computed tomography (CBCT) imaging methods before instrumentation. Root canal instrumentation was performed up to PTU F2 and F4 files. After instrumentation stages, the roots were scanned again with micro‐CT and then with CBCT in same parameters. All roots were sectioned horizontally at 2, 4, 6, 8, and 10 mm from the apices of the specimens. The sections were imaged under a stereomicroscope. Finally, imaging of the sections was done by scanning electron microscopy (SEM). Statistical data analysis of instrumentation steps was performed using Friedman and Wilcoxon tests, and the data of imaging methods were analyzed using Kruskal–Wallis and Mann–Whitney U tests (p = .05). Instrumentation with the PTU system up to F2 and F4 files significantly increased the number of microcracks compared with preoperative samples according to micro‐CT imaging (p < .05). For detecting microcracks on the root dentin, there were no statistically significant differences between micro‐CT (43.9%) and stereomicroscopy (45.8%) (p < .05). SEM showed significantly higher percentage of microcracks (88.3%) (p > .05). No microcrack was observed using the CBCT method. There were no statistically differences between micro‐CT and stereomicroscopy. SEM showed more dentinal microcracks while no microcrack was observed with CBCT.

Influence of voxel size on dentinal microcrack detection by micro-CT after root canal preparation

“…Micro-CT analysis allows visualization of preexisting and post-operative microcracks, thereby allowing each specimen to act as its own control. 40 However, the greater presence of preexisting microcracks may have induced a greater formation of microcracks during the preparation by HF-EDM. Therefore, within the limitations of this ex vivo study, it can be concluded that the voxel size should be considered as a potential factor for detecting microcracks when assessing micro-CT images.…”

Dentinal Microcracks after Root Canal Instrumentation Using Instruments Manufactured with Different NiTi Alloys and the SAF System: A Systematic Review

“…The main aim of endodontic therapy is to clean and fill the RCS in order to preserve or regain the integrity of the periapical tissues [45]. Despite continuous developments in instruments to improve RCS cleaning [46], dentin microcracks continue to be a source of concern for clinicians and researchers [47,48] as they often contribute to the instrumented tooth fracturing and extraction [49][50][51]. Although, there are multiple factors that contribute to dentinal crack formation like the design of the file, flexibility of file, and stress on the tooth surface used during instrumentation.…”

INCIDENCE OF DENTINAL DEFECTS AFTER ROOT CANAL PREPARATION USING HYFLEX EDM and MPRO FILES

“…Although these systems have different sequences (single files and multiple files) and configuration designs, they have one property in common; being made of memorized Ni-Ti alloys resulting from specific heat treatments. The external root surfaces were examined under a stereomicroscope to exclude the possibility of preexisting dentinal defects as it could lead to false results during microscopic evaluation owing to the propagation of these defects whether cracks or craze lines during the sectioning procedure itself as described by Çapar et al, (2019) (23). In addition, roots were surrounded with elastomeric impression material and embedded in acrylic resin mold to simulate the periodontal ligament during root canal preparation as explained by Ashwinkumar et al, (2014) ( 24) and Algarni et al, (2019) (25).…”

“…On the other hand, it has the following limitations; it permits examination of usually three or four specific levels with the chance of missing defects that might be related to other levels as described by Ustun et al,(2015) (29) and Rödig et al, (2019) (16). Also, this technique does not allow comparing pre and post-operative images of the same root, thus pre-operative micro-cracks might not be observed (23).…”