Evaluation of Threshold Values for Root Canal Filling Voids in Micro-CT and Nano-CT Images

While several materials and techniques have been used to assess the quality of root canal fillings in micro-CT images, the lack of standardization in scanning protocols has produced conflicting results. Hence, the aim of this study was to determine a cutoff voxel size value for the assessment of root canal filling voids in micro-CT and nano-CT images. Twenty freshly extracted mandibular central incisors were used. Root canals were prepared with nickel titanium files to an ISO size 40/0.06 taper and then filled with a single cone (40/0.06 taper) and AH Plus sealer. The teeth were scanned with different voxel sizes with either micro-CT (5.2, 8.1, 11.2, and 16.73 μm) or nano-CT (1.5 and 5.0 μm) equipment. Images were reconstructed and analyzed with the NRecon and CTAn software. Void proportion and void volume were calculated for each tooth in the apical, middle, and coronal thirds of the root canal. Kruskal-Wallis and post hoc Mann–Whitney U tests were performed with a significance level of 5%. In micro-CT images, significantly different results were detected among the tested voxel sizes for void proportion and void volume, whereas no such differences were found in nano-CT images (p>0.05). Micro-CT images showed higher void numbers over the entire root length, with statistically significant differences between the voxel size of 16.73 μm and the other sizes (p<0.05). The values of the different nano-CT voxel sizes did not significantly differ from those of the micro-CT (5.2, 8.1, and 11.2 μm), except for the voxel size of 16.73 μm (p<0.05). All tested voxel sizes enabled the detection of root canal filling voids except for the voxel size of 16.73 μm. Bearing in mind the limitations of this study, it seems that a voxel size of 11.2 μm can be used as a reliable cutoff value for the assessment of root canal filling voids in micro-CT imaging.Publisher's Versio

Impact of Virtual Reality Simulation in Endodontics on the Learning Experiences of Undergraduate Dental Students

Abstract: We aimed to evaluate the impact of Virtual Reality Dental Simulators (VRDS) on preclinical training in endodontics for undergraduate dental students. Purposive sampling technique was used to target undergraduate dental students at two dental schools: in Qatar and Turkey. After training on endodontic access cavity preparation on upper anterior teeth using acrylic teeth on dental mannequins and virtual reality haptic dental simulator, a questionnaire based on a combination of open- and closed-ended items was distributed to the participants. The sample included 60 dental undergraduate students. The participants reported positive experiences with VRDS and 76% considered it to be helpful in improving their fine motor skills. Endodontic access cavity preparation on VRDS was perceived to be similar to natural and acrylic teeth by 73.34% and 53% of participants, respectively. Overall, 85% of participants supported the use of VRDS training to supplement conventional training on dental mannequins but also recommended the need for improvements in VRDS training in endodontics. The findings of this study underscore the benefits of VRDS in endodontics. Future research involving larger samples from multiple institutions may help to optimize VRDS in undergraduate dental education

Micro-CT Evaluation of Centering Ability and Canal Transportation of Protaper Ultimate and RevoS+ Rotary File Systems in Simulated Curved Canals

Purpose A successful root canal preparation is to remove infected dentin and pulp tissue and to obturate the canal three-dimensionally. This study aimed to compare the centering ability of Protaper Ultimate and RevoS+ rotary file systems in curved canals of printed mandibular first molars by using micro-computed tomography (micro-CT). Materials and Methods In this in-vitro study, 16 mandibular molar teeth were printed from resin with 45° mesial root curvature. Root canal preparation was performed according to the specified groups, either Protaper Ultimate or RevoS+. The pre-and post-preparation images were repositioned in all three spatial planes by DataViewer. All images were imported into the CTAn software for the calculation of the centering ability and transportation values. Results The results showed no significant differences between the Protaper Ultimate and RevoS+ groups in terms of the centering ratio in the most inclined part of the canal. There were also no significant differences between the groups in canal transportation. (p>0.05) Conclusions Protaper Ultimate and RevoS+ rotary file systems showed similar ability in centering ratio and canal transportation in curved canals from printed mandibular molars

Resistance to Fracture of Dental Roots Obturated with Different Materials

The aim of this study was to compare the vertical fracture resistance of roots obturated with different root canal filling materials and sealers. Crowns of 55 extracted mandibular premolar teeth were removed to provide root lengths of 13 mm. Five roots were saved as negative control group (canals unprepared and unfilled). Fifty root canals were instrumented and then five roots were saved as positive control group (canals prepared but unfilled). The remaining 45 roots were randomly divided into three experimental groups ( = 15 root/group) and obturated with the following procedures: in group 1, glass ionomer-based sealer and cone (ActiV GP obturation system); in group 2, bioceramic sealer and cone (EndoSequence BC obturation system); and in group 3, roots were filled with bioceramic sealer and cone (Smartpaste bio obturation system). All specimens were tested in a universal testing machine for measuring fracture resistance. For each root, the force at the time of fracture was recorded in Newtons. The statistical analysis was performed by using Kruskal-Wallis and post hoc test. There were no significant differences between the three experimental groups. The fracture values of three experimental and negative control groups were significantly higher than the positive control group. Within the limitations of this study, all materials increased the fracture resistance of instrumented roots

Resistance to Fracture of Dental Roots Obturated with Different Materials

The aim of this study was to compare the vertical fracture resistance of roots obturated with different root canal filling materials and sealers. Crowns of 55 extracted mandibular premolar teeth were removed to provide root lengths of 13mm. Five roots were saved as negative control group (canals unprepared and unfilled). Fifty root canals were instrumented and then five roots were saved as positive control group (canals prepared but unfilled). The remaining 45 roots were randomly divided into three experimental groups (n = 15 root/group) and obturated with the following procedures: in group 1, glass ionomer-based sealer and cone (ActiV GP obturation system); in group 2, bioceramic sealer and cone (EndoSequence BC obturation system); and in group 3, roots were filled with bioceramic sealer and cone (Smartpaste bio obturation system). All specimens were tested in a universal testing machine for measuring fracture resistance. For each root, the force at the time of fracture was recorded in Newtons. The statistical analysis was performed by using Kruskal-Wallis and post hoc test. There were no significant differences between the three experimental groups. The fracture values of three experimental and negative control groups were significantly higher than the positive control group. Within the limitations of this study, all materials increased the fracture resistance of instrumented roots

Effect of Traditional and Conservative Endodontic Access Cavities on Instrumentation Efficacy of Two Different Ni–Ti Systems: A Micro-CT Study

This study aims to compare the shaping efficiency of the nickel–titanium instrument systems, One Reci and ProTaper Ultimate, using micro-CT (micro-computed tomography) in traditional and conservative endodontic access cavities. The experimental groups were formed according to the type of access cavity and Ni–Ti file system to be used. Sixty mandibular molar teeth were randomly divided into two main groups, the conservative access cavity (CAC) group and the traditional access cavity (TAC) group, and randomly divided into two subgroups according to the file system. The groups were compared with a two-way ANOVA analysis in terms of volume change, surface area, non-instrumented area transportation, and thickness of the dentin in the danger zone area after root canal preparation. The groups showed no statistically significant differences in terms of volume change, surface area, or the thickness of the dentin in the danger zone area after root canal preparation (p > 0.05). However, in the percentage of non-instrumented areas post-instrumentation between groups, the percentage of non-instrumented areas was statistically higher in specimens with CAC compared to TAC (p p < 0.05). Within the limitations of this study, CAC can also be used with some precautions as an alternative to TAC

The Implication of Virtual Reality Haptic Simulators on Cavity Preparation Proficiency in Dental Preclinical Education: A Systematic Review

Purpose: Preclinical education is an essential part of the dentistry curriculum. The purpose of this systematic review was to evaluate the contribution of the virtual reality haptic simulator to the improvement of cavity preparation skills in preclinical education. Materials and Methods: In this study, the effect of virtual reality was evaluated on the improvement of cavity preparation skills of preclinical students. Three separate databases were searched, and Endnote 20 software was used to duplicate, track, and manage the selection process. Results: After removing duplicate records, a total of 622 articles were initially retrieved in this study. All records were scanned, and 98 articles were evaluated for eligibility. Articles that did not meet the eligibility criteria of our study were excluded. 24 full-text articles were approved for review. Conclusion: Including virtual reality, haptic simulators in the curriculum can be a beneficial tool for students' manual dexterity and improvement of clinical practice

Multidisciplinary Approach for the Treatment of Horizontal Root-Fractured Maxillary Anterior Teeth

Dental trauma can lead to a wide range of injuries of which crown and root fractures are examples. Crown-root fractures often need complex treatment planning. This case report describes the use of MTA in the multidisciplinary management of a patient with a horizontally fractured central incisor and luxation in a different central incisor. A 42-year-old female patient presented within 1 h of receiving direct trauma to her maxillary area. Clinical examination revealed that the right and left maxillary central incisors presented mobility and sensitivity to percussion and palpation but no sensitivity to thermal stimulations. Occlusal displacement with extrusion in the left maxillary central incisor and luxation in the right maxillary central incisor was observed. Radiographic examination revealed horizontal root fracture at the apical third of the left maxillary central incisor. Root fracture in the right maxillary incisor was not observed. Endodontic and aesthetic restorative treatments were completed. MTA showed a good long-term outcome when used in root-fractured and luxated teeth. In addition, composite resin restoration provided satisfactory aesthetic results even after 15 months