Search

Aim: To determine the minimum dentin thickness in the mesial and distal walls of the mesiobuccal (MB) and mesiolingual (ML) canals of the mandibular first molars using cone-beam computed tomography (CBCT)., Materials and Methods: CBCT examinations of 624 mandibular first molars from an Indian subpopulation were analyzed. The mesial and distal minimum dentin thickness was evaluated in 1 mm intervals apical to the furcation area. Independent t -test was used to analyze the data ( α  = 0.05). Using Cohen's kappa coefficient, the interexaminer and intraexaminer reliability was evaluated., Results: The mesial dentin thickness was significantly higher than the distal dentin thickness for MB and ML canals ( P =0.01). The average dentin thickness in the distal and mesial plane of the MB canal was 1.15 ± 0.15 mm and 1.52 ± 0.19 mm at the 1 mm level and 0.83 ± 0.13 and 1.08 ± 0.18 at the 5 mm level, respectively. For the ML canal, the average dentin thickness in the distal plane and the mesial plane was 1.24 ± 0.18 mm and 1.44 ± 0.21 at the 1 mm level and 0.91 ± 0.16 and 1.01 ± 0.17 at the 5 mm level, respectively. Statistical analysis between the MB and ML canals showed significant differences in the dentin thickness at 4 and 5 mm levels in both the distal and the mesial planes ( P =0.01). In more than 85% of the cases, the minimum dentin thickness was seen at the 5 mm level in both the distal and mesial planes in MB and ML canals., Conclusion: The distal planes of the mesiolingual and mesiobuccal canals were thinner in most cases, making the distal surface more prone to iatrogenic perforations. Considerably, at 4 and 5 mm from the furcation, the distal wall was significantly thinner than the mesial walls. Understanding the anatomy of the danger zone in the mesial roots of the mandibular first molars may serve to minimize the risk of endodontic mishaps such as strip perforations., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2024 Sahil Choudhari et al.)

Objective: Computational fluid dynamic analysis (CFD) is claimed to be a reliable tool for analysing the fluid flow and the generated apical pressures in the simulated root canal. The current study aimed to analyse the apical pressures in extracted teeth with single and joining canals., Methods: Forty-six freshly extracted teeth were collected for the present study. The power was set at 95%, with an effect size of 0.55 (1-β=95%, α=0.05). Once the root canal anatomy was confirmed with cone-beam computed tomography (CBCT), they were divided into two groups: group I: mandibular second premolars with Vertucci type-I (n=23), and group II: maxillary second premolars with Vertucci type-II (n=23). The instrumentation of the specimens was carried out to a 0.04-taper using rotary instruments. A post-instrumentation CBCT was obtained, and computer-aided design models were obtained. The CFD simulations were then con- ducted with simulated 30-gauge side vented needles at 25, 50, and 75% short of the working length (WL)., Results: Group I recorded significantly (p<0.05) higher apical pressures at needle positions 25% short of the WL. However, no significant differences were elicited in the groups at other needle positions., Conclusion: Single canal specimens recorded higher apical pressures at needle positions 25% short of the WL. However, no differences were elicited between single and joining canals at higher needle positions.

Aim The present study aims to compare the antibacterial efficacy of a novel automated endodontic irrigation device with that of a manual irrigation technique. Materials and methods The present study considered 45 extracted single-rooted teeth. After sectioning the teeth, the specimens were inoculated with Enterococcus faecalis ( E. faecalis ) bacteria for three weeks. Instrumentation was done using ProTaper Gold rotary files to size 50 and 5% taper. Based on the irrigation protocol, the experimental samples were divided into Group I: control (normal saline irrigation) (n = 15); Group II: conventional needle irrigation (n = 15); and Group III: automated irrigation (n = 15). The irrigation in Group III was done using the automated irrigation device. After the experimental irrigation, the pre-weighted dentinal shaving was collected in Eppendorf tubes, diluted 10 times, and incubated in the Petri dish with tryptone soy agar (TSA) for 48 hours. Finally, the colony-forming unit (CFU) counts were assessed. IBM SPSS Statistics for Windows version 23.0 (Armonk, NY, USA, IBM Corp.) was used for data analysis. Intergroup comparisons were made using the non-parametric Kruskal-Wallis test. Results The mean CFU count (CFU/ml) for the groups was: Group 1 (normal saline irrigation): 3.67x10 1 ; Group 2 (manual irrigation): 2.69× 10 1 ; Group 3 (automated irrigation): 1.57× 10 1 . A statistically significant reduction in E. faecalis CFU count was seen among the groups assessed (p<0.01). The automated irrigation group exhibited the most substantial reduction in E. faecalis CFU count. Group 2 showed a significant difference compared to Group 1 (p<0.05). Conclusions The novel automated endodontic irrigation device was superior to manual irrigation in reducing E. faecalis CFU counts. This indicates that the automated irrigation device has the potential to enhance bacterial elimination efficacy during endodontic treatment., Competing Interests: Automated Irrigation Device (Indian Patent Copyright Application Number: 201941037185), (Copyright © 2023, Choudhari et al.)

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., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Selvaraj et al.)