Residual Dentin Thickness in Bifurcated Maxillary Premolars after Cervical Preflaring Preparation: A CBCT Analysis

Objective: This study evaluated the residual dentin thickness (RDT) of maxillary premolars after the use of different cervical preflaring (PF) drills by using cone-beam computed tomography (CBCT). Methods: Eighty bifurcated maxillary premolars were accessed and randomly divided into 5 groups (n=16). PF was performed with Gates-Glidden #1, #2, and #3 (group 1), Largo #1 and #2 (group 2), and LA Axxess #20/.06 (group 3), #35/.06 (group 4), and #45/.06 (group 5). CBCT images were acquired before (preoperative) and after (postoperative) PF. Initial and final cervical dentin thickness was measured at the buccal, palatal, mesial, and distal aspects, 0.5 mm coronally to the furcation, on both buccal and palatal roots, using CBCT’s image analysis software. The percentage of removed dentin after PF preparation was also calculated. Data were analyzed using ANOVA followed by Tukey’s test at a significance level of P < 0.05. Results: No statistically significant differences were found among the groups for preoperative or postoperative RDT (P > 0.05). LA Axxess #20/.06 (group 3) removed significantly less cervical dentin at all root canal aspects on both buccal and palatal roots. The mesial aspect of the buccal root and distal aspect of the palatal root were significantly reduced after the use of LA Axxess #45/.06 (group 5) and Largo #1 and #2 drills (group 2), respectively (P < 0.05). Conclusion: PF in bifurcated maxillary premolars should be performed with LA Axxess instrument #20/.06. The use of Gates-Glidden #1, #2, and #3, Largo #1 and #2, and LA Axxess #45/.06 drills should be done with caution.

Prevalence of complex root canal morphology in the mandibular first and second premolars in Thai population: CBCT analysis

Background Mandibular premolars demonstrate high variability in root canal morphology, especially mandibular first premolars. The purposes of this study were to determine the prevalence of root canal configurations of mandibular premolars according to Vertucci classification in a Thai population. Methods Total of 1159 CBCT images of Thai patients who received radiographic imaging at the Department of Radiology, Faculty of Dentistry, Chulalongkorn University in 2017–2018 was evaluated. The data were reported using descriptive statistics and the relationship between the prevalence of the root canal complexities and sex was analyzed using the chi-squared test. Results The most common root canal configuration was Vertucci type I, with a 63.1% and 98% prevalence in the mandibular first and second premolars, respectively. More than 98% of mandibular premolars had a single root. The prevalence of a bifurcation was 28.5% and 1.5% in the mandibular first and second premolars, respectively. The prevalence of a trifurcation was 3.2% in the mandibular first premolar. A C-shaped root canal was observed at 23.7% and 0.7% in the mandibular first and second premolars, respectively. The level of branching was mostly found at the middle 1/3 of the root. Bilateral appearance of the same root canal configuration was identified in 80.3% and 95.9% in the mandibular first and second premolars, respectively. There was no relationship between sex and the prevalence of a bifurcation, trifurcation, or C-shaped root canal. Conclusion Mandibular first premolars have more root canal complexities than mandibular second premolars. Horizontal tube shift x-ray technique, CBCT, dental operating microscope, and knowledge of root canal configurations have an important role in root canal identification in mandibular premolar with suspected complex root canal morphology.

Influence of Root Canal Fillings on Alveolar Bone Crest Level—An Observational Cross Sectional CBCT Analysis

The aim of this study was to compare the alveolar bone crest (ABC) level of root canal filled (RCF) teeth without apical periodontitis with corresponding non-filled teeth in the same individual using three-dimensionally cone-beam computed tomography (CBCT) data. Two hundred and thirty-five matching pairs of RCF teeth and corresponding teeth without RCF were selected from a pool of 580 random CBCT-images (voxel size 160–200 µm). Teeth with apical periodontitis, perio-endodontic lesions or surgical endodontic treatment were excluded. The distance between the cemento–enamel-junction (CEJ) and the ABC was assessed centrally mesial, distal, palatal/lingual and buccal at each tooth (∑1880 measuring points) in a standardized manner. Topographic, gender, and age-related relationships were also noted. Data were analyzed using the Kruskal–Wallis-test. The ABC-level between RCF teeth (2.64 ± 1.25 mm) and teeth without RCF (2.61 ± 1.16 mm) did not differ significantly (p > 0.05). No differences concerning localization (maxilla/mandible, tooth type) and gender (p > 0.05) occurred. Overall, ABC-level in the maxilla (2.74 ± 1.48 mm) was significantly lower (p < 0.001) compared to mandibular teeth (2.50 ± 1.41 mm). Patients >41 years had significantly lower ABC-levels than younger patients (p < 0.05). Men showed a reduced bone level compared to women (p < 0.05). In conclusion, RCF teeth are identical to their non-RCF counterparts, at least in terms of crestal bone level, regardless of the location or type of tooth and the gender of the patient. Thus, root canal treatment is an essential pillar for long-term tooth preservation.

Morphological Assessment of TMJ Spaces, Mandibular Condyle, and Glenoid Fossa Using Cone Beam Computed Tomography (CBCT): A Retrospective Analysis

Background The temporomandibular joint (TMJ) is included in the category of ginglymoarthrodial synovial joints. The mandibular condyle plays a vital part in the development of the craniofacial complex. Hence, the evaluation and assessment of the condylar volume and its morphology are of utmost importance. Aim The aim of this research was to use cone beam computed tomography (CBCT) imaging modality to evaluate the morphology of the mandibular condyle and glenoid fossa in a selected population and document any morphometric changes. Setting and Design It is an observational study. Materials and Methods A retrospective CBCT analysis was performed on 119 patients. The length, width, height, linear measurements of the joint spaces (anterior, posterior, and superior), volume of the condyle, and roof of glenoid fossa thickness were evaluated on both the left and right sides in both males and females. Results The height, width, and length of mandibular condyle were significantly increased in males on both sides. Except for the left anterior space, all other spaces were significantly larger in males. Overall, the volume of the condyles in males was significantly increased on both sides. Conclusion CBCT can be a valuable diagnostic aid in the evaluation of various dimensions, joint spaces, and condylar volume in different planes and thus, can be a useful predictor in the assessment of treatment outcomes of disorders affecting the TMJ.

Prevalence and Morphology of C-Shaped Canals: A CBCT Analysis in a Korean Population

This retrospective study of roots with C-shaped canals investigated their prevalence, configuration type, and lingual wall thickness, as well as the panoramic radiographic features of roots in permanent mandibular second molars confirmed to have C-shaped canals on cone-beam computed tomography (CBCT) in a Korean population. In total, 1884 CBCT images of mandibular second molars were examined by two endodontists to analyze the presence of C-shaped canals according to age and sex. The bilateral occurrence of C-shaped roots and their morphology on panoramic radiography were assessed and statistically analyzed using the chi-square test. The classification of Fan et al. was applied to categorize the configurations of C-shaped canals. The lingual wall thickness was calculated in the mesial, middle, and distal areas at the orifice and at 5 mm from the apex. The Mann–Whitney U test was used to analyze the mean difference of lingual wall thickness between the apex and orifice level. A P value of 0.05 was considered to indicate statistical significance in the statistical analyses. Of 2508 mandibular second molars, 924 (36.8%) had C-shaped root canals. The prevalence was significantly lower in the over 61 age group (24.08%) than in the 21–30-year age group (40.02%) and was higher in women (42.32%). Most cases were bilateral (85.9%). The C1 type was the most common (35.3%). The prevalence of C1 type canals decreased, while that of C3b type canals increased with age. In 75.2% of teeth having C-shaped root canals on CBCT, fused roots were observed on panoramic views. The difference in the lingual wall thickness at the orifice and 5 mm from the apex was significant in the middle area in all configurations of C-shaped root canals. When performing nonsurgical or surgical endodontic procedures of the mandibular second molars, clinicians should consider age, sex, ethnicity, and anatomical variations.

Comparison of CGRP distributions in the maxillary sinus and trigeminal ganglion between elderly dentulous and edentulous humans

Thickening of the Schneiderian membrane (SM, mucosa of the maxillary sinus) appears in the paranasal sinus. Information on SM thickening is available for patients receiving sinus lift treatments, which is a risk factor for SM excretory dysfunction. However, more information is needed on the structure of the SM and the relationship between the maxilla sinus and palatine with the alveolar bone and the SM for dental implant treatment in the human maxilla. One hundred twenty-six sides of the maxilla from 71 cadavers were subjected to cone-beam CT (CBCT) analysis and macroscopic and immunohistochemical observations in this study. A thickened SM was mainly observed in the middle region of the basal layer of the maxillary sinus (MS). Strong calcitonin gene-related peptide (CGRP)-positive reactions were observed in the alveolar bone, oral mucosa, mucosa of the maxillary sinus, and trigeminal ganglion (TG) cells in dentulous samples compared with edentulous samples. TG cells play important roles in delivering CGRP through axons to the mucosal gland and in regulating the maxilla-related thickening of the SM. These data could help determine CGRP functions in the mucosal gland and bone formation between dentulous and edentulous samples and indicate that CGRP may pass from the TG to the maxillary sinus glands.

Quality of Endodontic Treatment and Prevalence of Apical Radiolucencies in a Bulgarian Subpopulation: a CBCT Analysis

Introduction: The advent of Cone Beam Computed Tomography (CBCT) in endodontics has enhanced the diagnosis of periapical radiolucencies and the assessment of endodontically treated teeth.&nbsp; Aim: The purpose of this study was to assess the prevalence of periapical radiolucencies in a Bulgarian subpopulation and the quality of previous endodontic treatment using CBCT scans. Materials and methods: This study included 2795 roots from 160 Large FOV CBCT which were evaluated by two independent examiners using two scoring systems: CBCT-PAI and PESS.&nbsp; Results: The inter-examiner agreement spanned from strong to almost perfect (0.892 and 0.983). The prevalence of periapical lesions according to the two scoring systems was 23.1% and 12.9 %, respectively. The prevalence of endodontically treated teeth was high (34.1%). Sixty-five percent of them presented with signs of periapical radiolucencies, while only 1.4% of all non-treated roots had a periapical lesion. A significant association between periapical disease, poor quality of the root canal filling and inadequate coronal seal was found (p<0.001).&nbsp; Conclusions: The prevalence of periapical disease in endodontically-treated teeth in the Bulgarian subpopulation was high. Poor qual-ity of the root canal filling and inadequate coronal seal were assessed as prognostic determinants of treatment failure. CBCT techniques can augment conventional diagnostic techniques in the field of endodontics.&nbsp;