Molar root canal treatment performed by undergraduate dental students; an observational study of procedural errors and student perception.

BACKGROUND: Molar root canal treatment (RCT) is challenging and requires training and specific skills. Rotary instrumentation (RI) reduces the time needed for instrumentation but may increase the risk of certain procedural errors. The aims of this study were to evaluate the quality of molar RCTs provided by undergraduate students, to compare the prevalence of procedural errors following manual and RI, and to assess the students' self-perceived confidence to perform molar RCT without supervision and their preference for either manual or RI. METHODS: Molar RCTs performed by the final year students were evaluated radiographically according to predefined criteria (Appendix 1). The procedural errors, treatment details, and the students' self-perceived confidence to perform molar RCT and their preference for either manual or RI were recorded. Descriptive statistics were performed, and the Chi-squared test was used to detect any statistically significant differences. RESULTS: 60.4% of RCTs were insufficient. RI resulted in more sufficient treatments compared with MI (49% vs. 30.3% respectively. X2: 7.39, p = 0.007), required fewer visits to complete (2.9 vs. 4.6 respectively. X2: 67.23, p < 0.001) and was the preferred technique by 93.1% of students. The most common procedural errors were underextension of the root canal obturation (48.4%), insufficient obturation (45.5%), and improper coronal seal (35.2%) without a significant difference between the two techniques. 26.4% of the participating students reported that they did not feel confident to perform molar RCT without supervision. CONCLUSION: The quality of molar RCT provided by UG students was generally insufficient. RI partially improved the technical quality of RCT compared with MI. UG students need further endodontic training and experience before they can safely and confidently practise molar RCT.

Deep Margin Elevation - A Retrospective Clinical Study.

PURPOSE: The aim of this retrospective study was to assess the short- to mid-term restorative and periodontal outcome of deep margin elevation (DME) performed using resin composite. MATERIALS AND METHODS: Twenty-eight teeth treated with DME and indirect adhesive restorations were followed-up for a mean of 25.4 months (minimum: 12 months). Clinical and radiographic examination assessed the adaptation of the DME material and indirect restorations, presence of recurrent caries or discoloration, periodontal health at DME and non-DME sites, and periapical health. RESULTS: The overall success rate was 96.6%. One tooth showed signs and symptoms of apical pathology after 34 months following DME. No caries, discoloration, or periodontal pockets were detected in any of the treated teeth. DME had no detrimental effect on the gingival/periodontal health or plaque accumulation. There was no correlation between the distance from the DME material to the marginal bone level and pocket depth, gingival inflammation, and plaque accumulation (p > 0.05). CONCLUSION: Deep margin elevation might be considered a safe procedure for teeth with deep subgingival proximal caries in the short- and mid-term.

Prevalence and Configuration of the Second Mesiobuccal Canal in the Permanent Maxillary First Molar in Jordanian Population Sample.

Introduction: Missing a root canal during endodontic treatment implicates the persistence of microbial infection within the root canal system. This study aims to evaluate the incidence and morphology of the second mesiobuccal canal in the maxillary first molars in the Jordanian population. Methods and Materials: Consecutive cone-beam computed tomography (CBCT) scans taken at Jordan University Hospital were assessed in this retrospective study. A total of 200 scans that were examined, 111 were included in this study. The scans that were included had to have a full view of the maxilla with at least one permanent maxillary first molar. The following data were collected: the presence of a second mesiobuccal canal, the configuration of the mesiobuccal canals, the status of the apical area and the mesiobuccal inter-orifice distance, if applicable. The prevalence and morphology of the second mesiobuccal canal was determined and its association with biological sex and right or left sidedness was measured using the Chi-Square test. Results: The prevalence of the second mesiobuccal canal in our sample of the Jordanian population was 87%, with the most common canal configuration being Vertucci type II. The average inter-orifice distance between first and second mesiobuccal canals was 1.9 ± 0.4 mm. Conclusion: This retrospective study is the first in Jordan to document the prevalence of the second mesiobuccal canal using CBCT, and it shows that the vast majority of teeth have a second mesiobuccal canal. The proper location and negotiation of this canal is of dire importance for endodontic therapy.

Resistance to vertical fracture of MTA-filled roots.

AIM: To investigate the effect of MTA root canal fillings on the resistance to vertical root fracture (VRF) over different time intervals. MATERIAL AND METHODS: Freshly extracted anterior human teeth with single canals and minimal curvatures were decoronated, instrumented to size 50/.05 ProTaper file, irrigated with 1%NaOCl and randomly allocated to one of three groups (n = 36): (i) filled with MTA, (ii) filled with gutta-percha and sealer and (iii) unfilled roots used as a negative control. Each group was subdivided into three subgroups (n = 12) according to the storage time of 48 h, 1 and 6 months at 37°C in synthetic tissue fluid (STF). Following the storage periods, filled roots were mounted in acrylic supports, and the periodontal ligament was simulated using elastomeric impression material. Vertical loading was carried out with a ball-ended steel cylinder fitted on a universal testing machine at 1 mm/min crosshead speed. The maximum force at fracture (F-max) and the fracture mode were recorded for each root. RESULTS: Data were statistically analysed using two-way anova and Bonferroni post hoc tests. The mean F-max was significantly higher in the MTA subgroups after 1 and 6 months compared with all other subgroups. Two modes of fracture were identified: split and comminuted. The mean F-max values recorded with the latter were significantly higher compared with the former (P < 0.001). In all groups, split fracture was the most dominant mode apart from the MTA/1 month and MTA/6 month groups. CONCLUSION: MTA increases the resistance to VRF of endodontically treated teeth and influences the mode of fracture after 1 and 6 month of storage in STF compared with gutta-percha and sealer.

The effect of smear layer on the push-out bond strength of root canal calcium silicate cements.

INTRODUCTION: The aim of this study was to evaluate the effect of smear layer removal on the push-out bond strength between radicular dentin and three calcium silicate cements (CSC) in comparison with gutta percha and sealer. METHODS: Eighty human anterior extracted teeth were decoronated, cleaned and shaped to size 50/0.05 apically and randomly divided into 2 major groups: (A) smear layer preserved, and (B) smear layer removed using irrigation with 17% EDTA. Roots within each major group were further divided into 4 subgroups according to the obturation material used: (1) ProRoot MTA, (2) Biodentine, (3) Harvard MTA, (4) Gutta percha and AH-plus sealer. Obturated roots were stored in synthetic tissue fluid for 7 days to allow maximum setting of the root filling materials. Three 2-mm-thick slices were obtained from each root at different section levels (coronal, middle, apical). The canal diameters and slice thickness were measured, and the adhesion surface area for each slice was calculated. Push-out bond strength test was carried out using a universal testing machine. The bond failure mode was assessed under an optical microscope at 40×. RESULTS: The mean push-out bond strength in groups 1A, 2A and 3A were 7.54 (±1.11), 7.64 (±1.08) and 8.79 (±1.55)MPa respectively, while those for groups 1B, 2B and 3B were 6.58 (±1.13), 6.47 (±1.08), 7.71 (±1.81)MPa, respectively. In the gutta percha and sealer groups the push-out bond strength means were: 1.98 (±0.48) and 2.09 (±0.51)MPa in the preserved and removed smear layer groups respectively. The push-out strength values were significantly reduced when the smear layer was removed in the CSC groups (P<0.05) while no significant difference was detected in the gutta percha and sealer groups. CONCLUSIONS: Based on the conditions of this ex vivo study, it can be concluded that smear layer removal is detrimental to the bond strength between calcium silicate cements and dentin.

A micro-computed tomography evaluation of mineral trioxide aggregate root canal fillings.

INTRODUCTION: The aim of this study was to assess the effect of indirect ultrasonic activation on the incidence of voids within mineral trioxide aggregate (MTA) root canal fillings and at their interface with the canal walls by using a nondestructive 3-dimensional (3D) micro-computed tomography (micro-CT) analysis. METHODS: Extracted human teeth with single canals and minimal curvatures were decoronated, instrumented to size 50/05 apically, and randomly allocated into 4 groups (n = 12). MTA was compacted manually by using hand pluggers in group A (MC). Indirect ultrasonic activation was applied to each increment of manually compacted MTA for 1 second in group B (1 sec-UC), 5 seconds in group C (5 sec-UC), and 10 seconds in group D (10 sec-UC). Filled roots were scanned with a micro-CT device, and 3D analysis of void incidence was carried out by using the SkyScan software. RESULTS: Statistical analysis showed a significantly lower incidence of voids (P < .05) in the manual compaction (MC) group (0.7%) compared with the ultrasonic activation for 1 second (3.8%), 5 seconds (1.7%), and 10 seconds (1.6%) groups. CONCLUSIONS: Manual compaction produced significantly denser root fillings than those achieved with ultrasonic activation.