Stereomicroscopic Evaluation of Microcrack Formation in Dentin by ProTaper Next, Revo S, and WaveOne Gold File System

Abstract

Background: During the biomechanical preparation of the root canal by rotary file systems, stress is generated within the canal, which leads to dentinal microcrack formation. Such defects are evaluated only under the microscope. Aim: The present study aimed to evaluate dentinal microcrack formation after instrumentation with ProTaper Next (M-wire), Revo S (conventional NiTi), and WaveOne Gold (Gold-wire) file systems under the stereomicroscope. Materials and Methods: Forty single-rooted teeth free from any defect were selected and divided into four groups (Control, PTN, RS, and WOG). Experimental groups were instrumented with file system used in the study, and the control group were left unprepared. Samples were further decoronated and sectioned at 3 mm, 6 mm, and 9 mm from the apex perpendicular to the long axis and examined under a stereomicroscope at ×25 for different types of microcracks (no fracture, complete fracture, partial fracture, and other fracture). Statistical Analysis Used: Data analysis was done by the Chi-square test using the SPSS version 17.0 software. A two-sided (α = 2) P < 0.05 (P < 0.05) was considered statistically significant. Results: The null hypothesis was rejected. There was a statistically significant difference between the groups. All file systems created microcracks in the root dentin. WOG group showed an incidence of 66.7% for no fracture, PTN group had 40% for other fracture, and RS group had 60% for complete fracture. Conclusion: Single file system WOG with gold wire technology proves to be the best choice for canal preparation among the tested groups in terms of least dentinal crack formation.

Influence of Different Glide Path Techniques on Microcrack Formation after Two Different Root Canal Preparation Treatments: Micro Computed Tomography Analysis

“…There was a high level of newly formed microcracks in group MWOG, especially in the middle third (20.41%). This result contrasts a previous study, which found less crack formation occurred with WOG ( 20 ). This discrepancy may be due to the previously mentioned study being conducted on single-rooted teeth ( 20 ); hence, there would have been less contact between the instrument and root surface, resulting in minimal stress and less crack formation.…”

A comparative evaluation of dentinal defects after root canal preparation with different rotary and reciprocal systems

“…De-Deus et al 33 reported that the microcracks in the root dentin were caused by the extracted teeth, so the results of the studies reporting the presence of microcracks were flawed. Although it is not possible to exclude the possibility that these factors may also cause microcracks in root dentin (34), it is a strong evidence that no cracks were observed in the non-instrumented but sectioned control groups in several stereomicroscope studies (5)(6)(7)11,19,22,(35)(36)(37). Hereby, the aforementioned factors are unlikely to affect the findings (34).…”

Does Low-Taper Root Canal Shaping Decrease the Risk of Root Fracture? A Systematic Review

“…The differences in the results of the studies included in this revision are, therefore, attributable to many factors and are not related to the taper of the instrumentation used, but instead are probably related to: The difference in the preparation motion [ 48 , 55 , 56 ]; The cross-sectional profile and blade design [ 10 , 63 , 64 ]; The type of alloy of the instrument used [ 54 , 64 , 65 , 66 ]. …”