OBJECTIVE: Various anatomical variations of the inferior alveolar canal increase the incidence of surgical complications; Therefore, this study aimed to evaluate the frequency and configuration of bifid and trifid mandibular canals using cone beam computed tomography (CBCT) in the Turkish subpopulation.
METHODS: The inferior alveolar canal was evaluated on 1014 hemi-mandibles in the CBCT (I-CAT 3D Imaging System) images of 513 patients. The frequency and configuration of the bifid and trifid mandibular canal (MC) were examined. The relationship between bifid MC configuration and dental status and age groups was analyzed. The distance of the accessory canal to the buccal and lingual walls and the alveolar crest was measured. The diameter of the main canal and accessory canal was measured and its relationship with dental status and age groups was evaluated.
RESULTS: Bifid MC was found in 266 hemi-mandibles (24.7%) and 212 (41.3%) of 513 patients. The most common type of bifid MC was the retromolar canal (87 sides), followed by the forward canal without confluence (41; 4%) and the dental canal (34; 3.4%). 10 of the dental canals were opening to the 1st molar, 14 of the 2nd molars, and 10 of the 3rd molars. The number of retromolar foramina was 1 on 56 sides, 2 on 15 sides, and 3 on 4 sides. Forward canal without confluence was more common in edentulous patients than in dentulous patients, while the dental canal was more common in dentulous patients. The main canal diameter was 3.53 ± 0.97 mm and the bifid MC diameter was 1.82 ± 0.70 mm. Distance of the bifid MC to the lingual wall was higher in the > 64 years group than in the 18-39 years group (p = 0.022). Distance of the bifid MC to the alveolar crest was lower in the > 64 years group compared to the 18-39 years group and 40-64 years group (p = 0.015). The main canal diameter was higher in the 40-64 years group than in the 18-39 years group (p = 0.012).
CONCLUSIONS: Bifid MC has a high prevalence, occurring in almost one in two patients. Dental and retromolar types, which are close to the teeth, are more common, and this increases the possibility of complications. CBCT is the most accurate imaging technique used to detect and define these variations.

This clinical report presents a unique and previously unreported case of anatomical variations in the mandible, specifically involving the main mental foramen (MF), the mandibular canal (MC), and genial tubercles (GTs). The case involves a 21-year-old male seeking dental implant rehabilitation. The patient exhibited an unusual lingual exit path of the main left MF through the lingual cortical bone, with the MC following an anterior lingual direction along a lingual groove before exiting through the labial cortical bone between the apexes of the left canine and first premolar. Additionally, the patient displayed excessive enlargement and rare shape of the GTs. These rare anatomical findings presented challenges in dental implant planning. This case report emphasizes the importance of advanced imaging techniques like cone-beam computed tomography (CBCT) in evaluating mandibular structures for precise treatment planning and highlights the significance of understanding anatomical variations to prevent complications in dental procedures.

OBJECTIVE: To assess the prevalence and configuration of bifid (BMC) and trifid (TMC) mandibular canals using computed tomography (CT), describing the anatomical characteristics of the accessory canals, especially of the retromolar type.
METHODS: CT scans of 123 patients were analysed. BMCs were identified and the patterns of bifurcation were classified, including trifid canals. The width of accessory canals was measured. Retromolar canals were further classified according to their course and morphology, while their position and width were evaluated using linear measurements on CT images.
RESULTS: The majority of patients (53.6%) presented at least one BMC or TMC. 36.2% of mandibular canals were bifid, while 4.5% were trifid. The forward canals (12.6%) and retromolar canals (10.2%) were the most common among BMCs. In relation to the retromolar canals, 60% were vertical and 40% curved, with a mean width of 1.03 ± 0.28mm.
CONCLUSIONS: BMCs and TMCs are common 3D radiographic findings, so that they should be considered as anatomical variations, not anomalies. Preoperative CT or CBCT evaluation should aid in identifying these variations and analysing their position and course in surgical planning.

暂无摘要。

Background: This study evaluates the diagnostic accuracy of an AI-assisted tool in assessing the proximity of the mandibular canal (MC) to the root apices (RAs) of mandibular teeth using computed tomography (CT). Methods: This study involved 57 patients aged 18-30 whose CT scans were analyzed by both AI and human experts. The primary aim was to measure the closest distance between the MC and RAs and to assess the AI tool\'s diagnostic performance. The results indicated significant variability in RA-MC distances, with third molars showing the smallest mean distances and first molars the greatest. Diagnostic accuracy metrics for the AI tool were assessed at three thresholds (0 mm, 0.5 mm, and 1 mm). Results: The AI demonstrated high specificity but generally low diagnostic accuracy, with the highest metrics at the 0.5 mm threshold with 40.91% sensitivity and 97.06% specificity. Conclusions: This study underscores the limited potential of tested AI programs in reducing iatrogenic damage to the inferior alveolar nerve (IAN) during dental procedures. Significant differences in RA-MC distances between evaluated teeth were found.

OBJECTIVE: This study aims to develop a deep learning framework for the automatic detection of the position relationship between the mandibular third molar (M3) and the mandibular canal (MC) on panoramic radiographs (PRs), to assist doctors in assessing and planning appropriate surgical interventions.
METHODS: Datasets D1 and D2 were obtained by collecting 253 PRs from a hospitals and 197 PRs from online platforms. The RPIFormer model proposed in this study was trained and validated on D1 to create a segmentation model. The CycleGAN model was trained and validated on both D1 and D2 to develop an image enhancement model. Ultimately, the segmentation and enhancement models were integrated with an object detection model to create a fully automated framework for M3 and MC detection in PRs. Experimental evaluation included calculating Dice coefficient, IoU, Recall, and Precision during the process.
RESULTS: The RPIFormer model proposed in this study achieved an average Dice coefficient of 92.56 % for segmenting M3 and MC, representing a 3.06 % improvement over the previous best study. The deep learning framework developed in this research enables automatic detection of M3 and MC in PRs without manual cropping, demonstrating superior detection accuracy and generalization capability.
CONCLUSIONS: The framework developed in this study can be applied to PRs captured in different hospitals without the need for model fine-tuning. This feature is significant for aiding doctors in accurately assessing the spatial relationship between M3 and MC, thereby determining the optimal treatment plan to ensure patients\' oral health and surgical safety.

OBJECTIVE: Violations of the mandibular canal (MC) and mental foramen (MF) and subsequent injuries to their neurovascular bundle have been reported after surgical and nonsurgical dental procedures. Besides using advanced technologies such as cone-beam computed tomography (CBCT), clinicians should be aware of the anatomy and location of MC and MF in different populations. This study aims to describe the morphologic characteristics of the MF, MC, and its intrabony location in relation to the apices of mandibular posterior teeth in an Emirati subpopulation using CBCT.
METHODS: A total of 3700 CBCT scans were screened, and 154 scans that met the inclusion and exclusion criteria were randomly selected. The scans were assessed using 3-dimensional multiplanar imaging for the following structures: the location of MF and the MC course, its intrabony location, and its relationship to the apices of the mandibular posterior teeth. The data were analysed statistically using SPSS software.
RESULTS: The MC ran lingually and inferiorly at the posterior region and became more buccal and superior towards the MF. The distal root of the mandibular second molar was found to be the closest root to the MC (2.06 ± 1.83 mm). Moreover, the most common location of the MF was distal to the contact area between the 2 premolars (0.83 ± 1.84 mm) with a significant negative correlation to age (with and increase in age, the MF moves distally). The distance between the root apices and the MC was statistically significantly affected by age (positive correlation) and gender (male patients had a greater distance).
CONCLUSIONS: The common course of the MC is lingual and inferior posteriorly and becomes more buccal and superior towards the MF, which is located mostly between the mandibular first and second premolars. Furthermore, the distal root of the mandibular second molar is the closest to the MC and has a positive relationship with age.

OBJECTIVE: To assess the presence of mandibular canal bifurcation (BMC) and classify these variations by correlating findings with sex, age and facial skeletal pattern, measurements were made, including height, width, and distance from bifurcation to anatomical cortical bones.
METHODS: BMC was identified in cone beam CT exams of 301 patients and classified according to its origin, location, direction, configuration and ending. The height and width of the MC before and after the bifurcation; height and width of the BMC; and distance from BMC to alveolar (C1), buccal (C2), lingual (C3) and basal (C4) bone cortices were measured. All data were correlated with sex, age, and facial skeletal pattern (class I, II, III). The significance level was 5%.
RESULTS: 67 BMC (22.26%) were identified in 55 patients (18.28%). Bifurcations were more prevalent in females (p = 0.57), aged 18-39 years (p = 0.40), class I (p = 0.77). Single bifurcations, located in the posterior region of the mandible, originating in the MC, with a superior direction and ending in the retromolar foramen were more prevalent (p > 0.05). Mean cortical measurements were higher in male individuals, with significant differences only at C1 (p = 0.03). The mean height and width of BMC were 2.24 (± 0.62) and 1.75 (± 0.45) mm. There was no association between BMC classification and the variables studied (p > 0.05).
CONCLUSIONS: Approximately 1/5 of the population studied had BMC. There were no associations of BMC presence or characteristics with sex, age, and facial skeletal pattern. The distance from bifurcation to alveolar (superior) cortical bone is greater in male individuals.

UNASSIGNED: This study aims to compare differences in mandibular canal (MC) location between dentate and edentulous ridges, in the second premolar region as well as the first, second, and third molar regions using cone beam computed tomography (CBCT) of Arabic and Kurdish Iraqi populations.
UNASSIGNED: CBCT images of 400 subjects (200 Arabs, 200 Kurds) were collected from radiological archives. RadiAnt DICOM software (Medixant, Poland) was used for image analyses. Measurements were performed from MC to buccal and lingual alveolar crests and to buccal, lingual, and inferior aspect of the mandible for both dentate and edentulous ridges. Additionally, distance to the most superior aspect of residual edentulous ridge were performed. Independent t-test and Mann-Whitney U Test were performed utilising SPSS v.26.
UNASSIGNED: Distances from MC to buccal and lingual alveolar crests were consistently lower in edentulous ridge compared to dentate ridge across all teeth regions. Distances to lingual and inferior border of the mandible were higher in edentulous ridge compared to dentate ridge of all teeth regions. Distances to buccal surface of the mandible varies with fluctuations of dentate and edentulous ridges displaying higher measurements. Distance to superior aspect of residual edentulous ridge revealed mean values in the range of 13.45 to 15.69 mm in Arabs and 13.96 to 16.37 mm in Kurds.
UNASSIGNED: Discrepancy in vertical position of MC was observed between dentate and edentulous ridges within Arab and Kurd populations. Horizontal position of MC was unaffected by tooth loss and found to be closer to lingual surface of all molars. The residual alveolar ridge was sufficient to accommodate the common length and width of dental implants.
UNASSIGNED: The findings could play a crucial role in planning surgical interventions of the mandible, helping to prevent complications that might arise due to inadequate preoperative assessments.

A prospective cross-sectional study was conducted to correlate clinically, radiologically, and pathologically the mandibular invasion in carcinoma bucco-alveolar complex. All biopsy-proven oral cavity cancer cases (64 patients) were assessed clinically and radiologically for involvement of the mandible. Preoperative clinicoradiological findings were compared with postoperative histopathological findings. In our study, oral cancer was 4 times more prevalent in males as compared to females and clinical evaluation was found to be highly sensitive in predicting mandibular invasion. Orthopantomogram showed sensitivity of 66.6% and specificity of 100%. CT scan showed sensitivity of 100% and specificity of 46% whereas MRI showed sensitivity of 54.5% and a specificity of 96%. MRI correlates well with final histopathology in predicting size of tumor. Prevalence of bony invasion in carcinoma oral cavity was 18%. We noted an inverse relation with tumor differentiation and mandibular invasion, and none of the verrucous carcinoma lesions showed mandibular invasion. Association of clinical T and N staging with postoperative histopathology was found to be statistically significant. Despite recent advances in molecular biology, radiological techniques, and newer modalities like visual surgical planning, exact measurement of bone invasion is still challenging. At present, CT scan and MRI along with clinical evaluation are widely used to evaluate mandibular invasion in carcinoma oral cavity, and all these are complementary to each other. The recent progress in tissue engineering technologies and stem cell biology has significantly promoted the development of regenerative reconstruction of jawbone defects.