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

OBJECTIVE

This study aimed to evaluate the effect of WaveOne Glider (WOGG) with Waveone Gold (WOG) primary reciprocation systems on root dentine microcrack formation and to know the effect of TruNatomy Glider (TRNG) with TruNatomy (TRN) prime rotary systems on root dentine microcrack formation.

METHODS

In this study, 40 extracted mandibular first molar roots were selected and divided randomly into four groups (n=10). Group MWOG: a manual glide path was performed + WOG primary. Group MTRN: manual glide path performed+TRN prime. Additionally, group WOGG: glide path preparation with WOGG+WOG primary. Finally, for group TRNG, the glide path preparation was performed with TRNG+TRN prime. Micro-CT was used for pre and post-instrumentation image analysis. Statistical analysis was performed using the Kruskal- Wallis test (p<0.05) with Two-way ANOVA.

RESULTS

The Kruskal-Wallis test showed no significant differences among all groups in all thirds for pre and post-instrumentation regarding the crack formation. The Two-way ANOVA showed no significant difference or interaction between the ways of glide path preparation, whether manual or reciprocal WOGG, or between the rotary TRNG and the motion used in root canal preparation (rotary TRN or reciprocal WOG) regarding the crack formation and propagation.

CONCLUSION

Microcrack formation and propagation occurred independently of using different glide path techniques (manual, rotary, or reciprocal).

Comparative Evaluation of the Incidence of Dentin Microcracks Following Biomechanical Preparation Using Four Different Nickel-Titanium Rotary File Systems: An In Vitro Study

INTRODUCTION

Biomechanical preparation has gotten easier over time with the development of nickel-titanium (NiTi) rotary instruments. Despite their benefits, research has shown that these files frequently result in microcracks in the root canal dentin, which can fracture the roots. Such mishaps should be prevented, as they compromise the integrity of the root and reduce the long-term survival of endodontically treated teeth.

MATERIALS AND METHODS

This study was conducted at Government Dental College and Hospital, Patiala, Punjab, India. Eighty permanent mandibular premolar teeth were included. All the roots were inspected for any pre-existing cracks or craze lines under a stereomicroscope. The teeth were decoronated and then divided into four groups (n = 20): Group I: TruNatomy, Group II: Neoendo Flex, Group III: ProTaper Gold, and Group IV: 2Shape. The samples were instrumented according to the group to which they belonged. The roots were then sectioned horizontally at 3 mm and 6 mm from the apex and examined under a stereomicroscope at 40x for the presence of microcracks.

RESULTS

The data were analyzed using the IBM SPSS Statistics for Windows, version 26 (released 2019; IBM Corp., Armonk, New York, United States). A chi-square test was applied, and the level of significance was set at p < 0.05. The highest incidence of microcracks was associated with ProTaper Gold (65%), followed by Neoendo Flex (45%), TruNatomy (20%), and 2Shape (20%).

CONCLUSION

 All rotary instruments resulted in dentinal damage. ProTaper Gold exhibited the highest frequency of dentin cracks. TruNatomy and 2Shape exhibited satisfactory results with minimal crack formation.

Comparative Evaluation of Dentinal Crack After Root Canal Preparation Using TruNatomy, Neoendo Flex, and Neoendo Neohybrid Files: An In Vitro Study

AIM

The objective of the study was to assess and compare the dentinal microcracks produced by TruNatomy, Neoendo Flex, and Neoendo Neohybrid files during root canal preparation.

MATERIAL AND METHODS

In this in vitro investigation, four groups of 25 samples each were assembled from 100 mandibular premolar teeth. Using TruNatomy, Neoendo Flex, and Neoendo Neohybrid files, or leaving the teeth unprepared (control), the teeth underwent root canal preparation. Horizontal sections were taken at different distances from the apex to analyze dentinal cracks. A stereomicroscope was used to assess the existence or lack of cracks, and chi-square tests were performed on the data.

RESULTS

In the control group, there were no cracks. TruNatomy files created fewer cracks compared to Neoendo Flex and Neoendo Neohybrid files.

CONCLUSIONS

This in vitro investigation demonstrates that the root surface might acquire dentinal cracks as a result of nickel-titanium instruments. Compared to Neoendo Flex and Neoendo Neohybrid files, TruNatomy showed a decreased incidence of cracks. However, it is important to note that these conclusions are limited to the scope of this study.

Scanning Electron Microscopic Analysis of Deformation of TruNatomy File Systems: An Ex-vivo Study

Aim The aim of the study was to assess the instrument deformation following the usage of the TruNatomy (Dentsply Sirona, USA) file system in extracted premolars using Scanning Electron Microscopy (SEM). Materials and Methods For the present study, 84 extracted mandibular bicuspids were selected. The teeth were divided into two groups: Group 1, TruNatomy (n=42), and Group 2, Hero Shaper (Micro Mega, France) (n=42). The samples were shaped with 0.03 taper to size 36 with TruNatomy instruments and 0.04 taper to size 30 with Hero Shaper instruments. 5 ml of 5.25% Sodium Hypochlorite (NaOCl) and 2 ml of 17% ethylenediaminetetraacetic acid (EDTA) were used for the final irrigation of root canals. The master apical file was used to instrument seven teeth samples for assessing the safety of the instruments after multiple uses and autoclaving. So, a total of six files per group was used for the analysis of any distortions, cracks or micro-fractures after instrumentation of 42 teeth, at the tip (D0) and 5 mm from the tip (D5) of the rotary file under SEM at 500x magnification. Statistical analysis To determine the significance between the groups, the Mann-Whitney U-test was applied. Results The mean surface wear of the instruments, at the tip (D0) in Group 1 was 1.2857 and in Group 2 was 1.4762. The mean spiral distortion of the instruments, at the tip (D0) in Group 1 was 1.1905 and in Group 2 was 1.4286. A statistically significant difference (P<0.05) was observed between the groups for surface wear and spiral distortion at the tip of the file (D0). There was no significant difference between groups for surface wear and spiral distortion values of the instruments at 5 mm from the tip (D5) (P>0.05). Conclusion The instrument distortion of the rotary file systems analysed was minimal following the biomechanical preparation of seven mandibular bicuspids without root curvature, using a single file. Therefore, both rotary file systems can be considered safe.

Comparative Evaluation of Debris Extrusion, Remaining Dentin Thickness and Fracture Resistance of Endodontically Treated Teeth Using Rotary and Reciprocating Endodontic File Systems: An In Vitro Study

BACKGROUND

Preventing the apical extrusion of debris during instrumentation is of paramount importance to reduce the occurrence of flare-ups in endodontically treated teeth. Furthermore, an essential requirement for the longevity and strength of an endodontically treated tooth and its ability to resist fracture is the preservation of residual dentin thickness during instrumentation. The aim of this study was to compare the amount of debris extrusion, remaining dentin thickness at the coronal third, middle third, apical third, and the fracture resistance of the teeth using rotary (TruNatomy; Dentsply Sirona, Charlotte, NC) and reciprocating (WaveOne Gold; Dentsply Sirona) endodontic file systems.

METHODS

An in vitro study included 52 single-rooted, oval canal shaped teeth that underwent exploration and initial cleaning with a no. 15 K-file. The prepared canals were then randomly assigned to two groups: Group I, with instrumentation with the TruNatomy rotary file (n=26) and Group II, with instrumentation with the WaveOne Gold reciprocating file. Parameters like debris extrusion, remaining dentin thickness, and fracture resistance were evaluated in both the groups. Analysis was performed using a paired t-test for the assessment of difference between groups and one-way ANOVA test followed by the post-hoc Tukey test for difference between the coronal, middle and apical third for each study group.

RESULTS

The results revealed no significant difference (t=0.454, p=0.652) between the TruNatomy rotary file and WaveOne Gold reciprocating file in apical extrusion of debris after their use in root canal therapy. For the remaining dentin thickness, a significant difference was present between the TruNatomy rotary file and WaveOne Gold reciprocating rotary file at the coronal (t=5.766, p<0.0001) and middle (t=3.690, p=0.001) levels. The mean fracture resistance was significantly more (t=15.877, p<0.0001) with the TruNatomy rotary file compared to the WaveOne Gold reciprocating rotary file.

CONCLUSION

The TruNatomy rotary file system outperformed the WaveOne Gold reciprocating file system in terms of maintaining the remaining dentin thickness and providing improved fracture resistance. Nevertheless, debris extruded apically was comparable between the TruNatomy rotary file system and the WaveOne Gold reciprocating file system.