Assessment of the Prevalence of Radix Entomolaris and Distolingual Canal in Mandibular First Molars in 15 Countries: A Multinational Cross-sectional Study with Meta-analysis

Detection of three-rooted mandibular first molars on panoramic radiographs using deep learning

This study aimed to develop a deep learning system for the detection of three-rooted mandibular first molars (MFMs) on panoramic radiographs and to assess its diagnostic performance. Panoramic radiographs, together with cone beam computed tomographic (CBCT) images of the same subjects, were retrospectively collected from 730 patients, encompassing a total of 1444 MFMs (367 teeth were three-rooted and the remaining 1077 teeth were two-rooted). Five convolutional neural network (CNN) models (ResNet-101 and - 50, DenseNet-201, MobileNet-v3 and Inception-v3) were employed to classify three- and two-rooted MFMs on the panoramic radiographs. The diagnostic performance of each model was evaluated using standard metrics, including accuracy, sensitivity, specificity, precision, negative predictive value, and F1 score. Receiver operating characteristic (ROC) curve analyses were performed, with the CBCT examination taken as the gold standard.Among the five CNN models evaluated, ResNet-101 demonstrated superior diagnostic performance, and the AUC value attained was 0.907, significantly higher than that of all other models (all P < 0.01). The accuracy, sensitivity, and specificity were 87.5%, 83.6%, and 88.9%, respectively. DenseNet-201, however, showed the lowest diagnostic performance among the five models (all P < 0.01), with an AUC value of 0.701 and an accuracy of 73.2%. Overall, the performance of the CNNs diminished when using image patches containing only the distal half of MFMs, with AUC values ranging between 0.680 and 0.800. In contrast, the diagnostic performance of the two clinicians was poorer, with AUC values of only 0.680 and 0.632, respectively. In conclusion, the CNN-based deep learning system exhibited a high level of accuracy in the detection of three-rooted MFMs on panoramic radiographs.

Relationship of incidence of radix entomolaris and C-shaped canal in mandibular molars using CBCT: A multi-centre study

This study aimed to evaluate the relationship of incidence between radix entomolaris (RE) in permanent mandibular first molars (FM) with C-shaped canal (CSC) in permanent mandibular second molars (SM). A total of 1015 cone-beam computed tomography (CBCT) images of permanent mandibular molars from Malaysian patients were collected retrospectively and analysed by researchers from seven dental schools in Malaysia trained in CBCT technology. The presence and absence of RE and CSC were scored as 'yes' or 'no'. The prevalence of FM with RE was 21.2% and SM with CSC was 37.9%. The co-occurrence of RE and CSC in the same quadrant was 6.5% (OR = 1.497, p = 0.014). Female, Chinese and samples from Eastern Peninsular Malaysia were associated with CSC in SM (p < 0.05). The increased appearance of CSC in SM when RE is present in FM makes it imperative for clinicians to be vigilant during examination and diagnosis to prevent potential endodontic mishaps.

Investigation of the furcation morphology of permanent mandibular first molars by using micro-computed tomography

BACKGROUND

To investigate the anatomic features of the root furcation of permanent mandibular first molars.

METHODS

A total of 50 extracted mandibular first molars (25 two-rooted and 25 three-rooted) were collected and scanned using micro-computed tomography. The digital models of teeth and root canal systems were reconstructed three-dimensionally. The tooth models were displayed in parallel projection mode from buccal and distal views. Screenshots were captured and subsequently analyzed using Image-Pro Plus 6.0 software after calibration. The furcation angle, root trunk length, maximum depth and level of distal root concaves of mesial roots, and length of enamel projections were measured, and the furcation types (classified into type V, type U and type W) were detected. Statistical analysis was performed using the Shapiro-Wilk's test, one-way analysis of variance, Student's t-test and Chi-square test.

RESULTS

The mean furcation angle between the distobuccal (DB) and distolingual (DL) roots (in distal view) was the greatest (59.2°), whereas the furcation angle between the mesial and DL roots (in buccal view) was the smallest (25.4°) among the four furcation angles (all p < 0.05). Regarding the furcation types, bucco-lingual root trunk length, maximum depth and site of the distal root concavities, and enamel projection length, no significant differences were detected between the three- and two-rooted molar groups (all p > 0.05). The frequency of type V was the highest (54.0%), followed by type U (26.0%), and type W had the lowest occurrence rate (20.0%). The mean length of distal root trunk in the three-rooted mandibular molars was significantly greater than that of the buccal/lingual one (3.7 mm vs. 3.0 mm, p < 0.01). The maximum depth of the distal concavities of the mesial roots was on average 0.66 ± 0.19 mm, and the site was located at an average of 2.8 ± 1.3 mm below furcation. The mean length of buccal enamel projections was significantly longer than that of lingual ones (3.1 mm vs. 0.7 mm, p < 0.01).

CONCLUSIONS

The furcation anatomy of the mandibular first molar is complex, and the presence of the DL root may further complicate its topography. A thorough understanding of these anatomic features is essential for successful periodontal treatment.

Prevalence of radix accesoria dentis in a northern Peruvian population evaluated by cone-beam tomography

Radix accessoria dentis are anatomical variations of the mandibular molars and identifying them radiographically can be challenging for the clinician, especially in specific areas such as endodontics. The objective this study was to determine the prevalence of radix accessoria dentis evaluated in cone-beam computed tomography in a northern Peruvian population. The study design was descriptive and cross-sectional. The sample consisted of 2640 permanent mandibular first and second molar teeth evaluated by cone beam tomography. Non-probabilistic convenience sampling was used. For the analysis of radix accesoria dentis, the axial and coronal views of the tomography were evaluated. Prevalence was evaluated according to sex and according to type of tooth and average length. The statistical analyses used were the chi-square test and Kruskal-Wallis H test to find the correlation of the variables. A prevalence of 2.5 % of radix accesoria dentis was determined. According to sex, radix accesoria dentis was present in 1.36 % in females and 1.14 % in males (p > 0.05). The tooth 4.6 obtained the highest prevalence with 1.33 % (p > 0.05) and the average length of radix accesoria dentis found was 9.27 mm (p > 0.05). The prevalence of the radix accesoria dentis evaluated in cone beam tomography in a northern Peruvian population is low. Sex does not influence its presentation. Mandibular first molars are the ones that present the greatest amount of this anatomical variation and the average length of the radix accesoria dentis is less than 10 mm.

Root canal morphology of anterior permanent teeth in Jordanian population using two classification systems: a cone-beam computed tomography study

BACKGROUND

Adequate knowledge of root canal morphology and its variation is essential for success of root canal treatment and to overcome treatemnt failure. The aim of this study was to investigate the root and canal morphology of mandibular anterior teeth using 2 classification systems.

METHODS

3342 lower anteriors were evaluated from 557 CBCT scans. The images were examined in sagittal, axial and coronal views using a CS 3D imaging software (V3.10.4, Carestream Dental). Demographic data recorded, the number of roots and canal's morphology were described according to Vertucci and Ahmed classifications.

RESULTS

Frequency of Type I configuration was significantly the highest in incisors and canines (76%, N = 2539), followed by Type III (20.6%, N = 687). Type II (1.1%, N = 37), IV (1.1%, N = 37), and V (0.3%, N = 11) were rarely encountered. 0.9% (N = 31) of the teeth could not be classified with the Vertucci System. The frequency of 2 roots (2MA in Ahmed classification) which has no correspondence in the Vertucci classification, was 1.1% (N = 38), it was significantly higher in canines and in females (35 canines and 3 laterals). A moderate correlation in root canal morpology was found between the left and right sides (V > 0.30). 80% (N = 2538) of the teeth did not exhibit any divergence/merging. The bifurcation level occurred mostly in the middle third of the root.

CONCLUSIONS

One fourth of anterior teeth had variation from the simple type I canal configuration and therefore requires attention during treatment. The new classification system offers a more accurate and simplified presentation of canal morphology.

CLINICAL RELEVANCE

The prevalence and mid root bifurcation of second canal in lower anteriors requires attention to ensure adequate quality root canal treatment without compromising the integrity of teeth.

The association of endodontic prognostic factors with the presence of periapical lesion, its volume, and bone characteristics in endodontically treated molars: a cross-sectional study

BACKGROUND

This study intended to evaluate the association between several endodontic prognostic factors with the presence of periapical lesions (PLs), their volume, and bone characteristics including cortical bone destruction (CBD) and buccal plate bone height (BPBH) in root-filled molar teeth using cone-beam computed tomography.

METHODS

A collection of 143 scans of endodontically treated maxillary/mandibular first or second molars recorded over 8 years, were obtained from a specialized radiology center. Data on prognostic factors including tooth number, gender, jaw type, the status and number of missed canals, obturation length, restoration type, presence of a separated instrument, presence of a post or screw in the canals, and presence of perforation were collected. The assessed outcomes included PL presence, PL volume, CBD, and BPBH. The association between prognostic factors and outcomes was evaluated using multiple logistic regression models with adjusted covariates and multifactorial ANOVA at a significance level of 0.05.

RESULTS

A total of 282 molars from 82 women and 50 men with a mean age of 40.6 ± 12.27 were included. Among those, 139 teeth presented PL with a mean volume of 18.68 mm3. CBD was prevalent in 137 teeth and the mean BPBH appeared to be 9.45 mm. The presence of a missed canal (OR = 10.022, P < .05), underfilled canal (OR = 3.725, P < .05), overfilled canal (OR = 15.859, P = .018), and perforation (OR = 15.261, P = .013) was significantly associated with PLs. None of the prognostic factors could considerably contribute to the CBD (P > .05). The presence of a missed canal was positively associated with the PL volume (P < .05). Similarly, missed canals (P < .05), perforation (P < .05), and separated instruments (P = .004) were associated with a significantly reduced BPBH.

CONCLUSIONS

Overfillings, perforations, missed canals, and underfillings were identified as remarkable predictors of PL, arranged in descending order of their respective impact. The only factor capable of significantly increasing the PL volume was the missed canal. In brief, obturation length errors, perforations, missed canals, and separated instruments were robustly correlated with endodontic failure, which highlights the importance of mitigating the potential for errors by following the fundamentals of endodontics.

Locating and Treating Three Calcified Canals in a Mandibular First Molar With Radix Entomolaris and Five Canals: A Case Report

The success of root canal treatment is highly contingent on the comprehensive shaping, cleaning, and filling of the entire root canal system. Failure to address one or more canals often results in an increased likelihood of post-treatment apical periodontitis. Typically, mandibular first molars feature two roots and three canals, but they may also exhibit anatomical variations, such as a mesial middle canal or radix entomolaris (RE). This article presents a case where three calcified canals in a mandibular first molar with RE and five canals were successfully located and treated.

A Cone Beam Computed Tomography-Based Investigation of the Frequency and Pattern of Radix Entomolaris in the Saudi Arabian Population

Background and Objectives: An understanding of the anatomical complexity of teeth is a significant factor for a successful endodontic treatment outcome. The aim of this study was to explore the frequency and pattern of distribution of radix entomolaris (RE) in mandibular first molars (MFMs) of a Saudi Arabian subpopulation using CBCT scans. Materials and Methods: This study was conducted at dental clinics of Qassim University from February to May 2023 by evaluating CBCT scans that were previously obtained for diagnostic purposes. Scans of Saudi national patients with bilaterally present MFMs and fully formed root apices were included. Conversely, scans with one/or two missing MFMs, MFMs with incomplete root apices, full- or partial-coverage prosthesis, endodontic treatment, and associated radicular resorption were excluded from study. A total of 303 CBCT scans with 606 bilateral MFMs were analyzed by two calibrated evaluators for the presence of, and type according to Song's typolgy of RE. The data were analyzed using SPPS-24. The descriptive variables were documented as frequencies and percentages. The chi-square test was used to determine the association between the prevalence of RE with the gender, jaw side and age group. Both inter-rater and intra-rater agreements were estimated for detecting and classifying RE using Cohen's kappa test. Results: The sample had 63.7% males and 36.3% females. The prevalence of RE was 6.6%, with Song's type III (57.5%) as the most common variant. Absolute agreement was noted between the raters about the presence of RE and very strong agreement was noted for the classification of the RE. Conclusions: RE is an uncommon finding among the mandibular first molars of the Saudi population without any gender and quadrant predilection. The clinicians' knowledge of the presence and Song's type of RE may contribute towards the enhancement of endodontic treatment outcomes.

Prevalence of Radix Entomolaris in Mandibular Permanent Molars Analyzed by Cone-Beam CT in the Saudi Population of Ha'il Province

BACKGROUND

The present study aimed to examine the prevalence of radix entomolaris (RE) in the mandibular permanent molar within a specific sub-population in Saudi Arabia.

METHODS

A comprehensive analysis was conducted on 499 cone-beam computed tomography (CBCT) scans of a mandibular molar from a sample of Saudi patients aged between 18 and 65. The primary objective of this study was to investigate the anatomical characteristics of mandibular permanent molars, specifically focusing on the number of roots present. The chi-square test was employed to examine the relationship between various variables.

RESULTS

In the case of mandibular first molars, it was observed that 95.3% of these molars exhibited a bifurcated root structure. In comparison, the remaining 4.7% displayed a triradicular configuration within the sample population under investigation. Although there were some variations, no significant differences in the number of roots were observed between males and females or left and right sides (p > 0.05). In the case of mandibular second molars, it was observed that 96.9% of them exhibited a bifurcated root structure, whereas 2.5% displayed a trifurcated root configuration, and a mere 0.6% possessed a single root. There were no statistically significant variations in the number of roots between males and females or left and right sides (p > 0.05).

CONCLUSIONS

The identification of RE was observed in the mandibular molars. Moreover, the discovered RE roots were predominantly found in the mandibular first molar, displaying a tendency for bilateral occurrence in both male and female individuals.