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Objective: This randomised clinical study aimed to assess the influence of low-dose cone-beam computed tomography (CBCT) on the visibility of the mandibular canal (MC) and its proximity to mandibular third molars (M3Ms) as assessed by general dental practitioners (GPs) and oral-maxillofacial surgeons (OMFSs), as well as its impact on their clinical decisions, when compared to standard-dose CBCT. Methods: 154 impacted M3Ms from 90 patients were randomly assigned to three groups for two CBCT exposures using one standard-dose (333 mGy×cm2) and one of the three investigated low-dose (78–131 mGy×cm2) protocols. Blinded assessments of the MC visibility, M3M-MC proximity, surgical approach, crown/root sectioning, and referral decisions, were made by GPs and OMFSs on the images separately. Pairwise comparisons for MC visibility between paired scans were evaluated using Wilcoxon signed rank test, followed by a non-inferiority test with non-inferiority margin of 0.5 on a four-point scale. Differences in other variables between paired scans were evaluated using Wilcoxon signed-rank or McNemar tests. Results: The majority (78.5–99.3%) of MCs were clearly identified on standard-dose CBCT by all observers. Pairwise comparisons showed significant differences between paired scans only in MC visibility but not in the M3M-MC proximity or treatment decisions. The mean differences in MC visibility between paired scans ranged 0-0.22 with the upper bounds of the 95% confidence intervals (0.09–0.36) falling within the non-inferiority region. Conclusions: The investigated low-dose CBCT protocols could provide acceptable image quality for the evaluation of impacted M3Ms in most cases. When compared to standard-dose CBCT, these low-dose CBCT images did not significantly affect the assessments of the M3M-MC proximity, treatment strategies, and patient management decisions made by GPs and OMFSs. Clinical relevance: The low-dose protocols might be clinically acceptable for M3M management while greatly reducing radiation exposure. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the influence of combining levels of metal artifact reduction (MAR) tool with different filters and slice-thickness in the detection of mandibular canals perforated by implants on CBCT scans and to objectively assess the impact of the aforementioned combinations. Materials and methods: Implants were placed above (8 implants) and inside (10 implants) mandibular canals of dried-mandibles. CBCT scans were obtained with the Eagle 3D unit (85 kVp, 8 mA, 5 × 5 cm FOV, 130 μm voxel size, and off/medium/high MAR levels). Examiners evaluated the scans under each MAR level and across different conditions: no filter, Sharpen 1×, Sharpen 2×; 0 mm, 1 mm, and 2 mm slice-thickness. The gray values on axial reconstructions were assessed. Area under the receiver operating characteristic curve (AUC), sensitivity, specificity, mean and standard deviation (SD) for gray values were calculated and compared by multi-way Analysis of Variance. Results: Overall, the AUC and sensitivity decreased with high-level MAR (p < 0.0001), regardless other variables tested. Enabling MAR tool decreased mean gray values (p < 0.01) and increasing MAR levels reduced the SD values on scans with Sharpen 2× (p < 0.012). Conclusions: High-level MAR impairs the visualization of mandibular canals perforated by implants. Moreover, enabling MAR tool decreases the mean gray values. Clinical relevance: MAR tool, filters, and slice thickness influence the image quality of CBCT scans. Therefore, it is important to evaluate the impact of these parameters on the diagnosis of mandibular canals perforated by implants. [ABSTRACT FROM AUTHOR]

Given the high prevalence of skeletal and mandibular diseases in the Patagonian Huemul, comprehensive anatomical studies are essential to understand the impact of nutritional deficiencies and support conservation efforts. The aim of this study is to provide a detailed anatomical characterisation of three exhumed mandibles of Patagonian huemul (Hippocamelus bisulcus) through three‐dimensional reconstructions obtained from computed tomography data and semi‐automatic segmentation, documenting their distinctive features. The findings revealed distinctive features in the mandible, consistent with the browsing habits of herbivores, such as a robust coronoid process, a wide and deep pterygoid fossa, a significantly lower mandibular condyle compared to other deer species and a unique configuration of the mandibular canal with a curved caudal portion and a straight rostral portion. These anatomical adaptations are likely related to the species' feeding habits and behaviour. The study also addressed the challenges of researching an endangered species, given that access to biological material is restricted by strict regulations in Chile and Argentina. These restrictions limited the available sample size and hindered the acquisition of additional specimens, which could affect the generalisation of the results. Despite these limitations, the research provides valuable anatomical insights that are fundamental for the biology, clinical practice and management of specimens. In conclusion, the mandibles of both juvenile and adult Patagonian huemul demonstrate distinctive features characteristic of browsing herbivores. The findings can serve as a basis for future comparative studies on mandibular anatomy and function in this endangered deer species as well as in other herbivorous deer. [ABSTRACT FROM AUTHOR]

The mandibular canal rarely penetrates the apically fused tooth roots. In this report, we describe three cases of patients in whom the mandibular canal ran between the roots of embedded mandibular teeth with apical fusion. Case 1: A 43-year-old man presented with a completely embedded left mandibular first molar and a swollen gingiva. Cone beam computed tomography revealed apical root fusion and a mandibular canal penetrating the root. Case 2: Cone-beam computed tomography of a 39-year-old female revealed root apical fusion and a mandibular canal between the roots. Case 3: Cone-beam computed tomography of a 30-year-old female with a fully erupted left mandibular third molar revealed a ring of diverging roots fused to the root apex. The mandibular canal runs between the mandibular roots. All three patients were treated under general anesthesia and developed postoperative inferior alveolar nerve palsy; however, their sensory function recovered over time. The prognosis was good in all patients, none of whom experienced any other complications. [ABSTRACT FROM AUTHOR]

CONTEXT: The mandibular canal (MC) is an essential landmark that should be considered before any surgeries. Therefore, accurately assessing the location and characteristics of the MC in cone beam computed tomography (CBCT) imaging is very important. AIMS: To determine the characteristics of the MC in relation to adjacent anatomical structures in CBCT projections. SETTINGS AND DESIGN: The convenience sampling method. METHODS AND MATERIAL: This was a retrospective study of 112 CBCT images of Vietnamese patients aged 18 to 69 years, taken for clinical indications between 2018 and 2023. The evaluation was carried out by comparing and arranging the anatomical structures of different planes in three-dimensional space to assess and measure relevant dimensions. STATISTICAL ANALYSIS USED: Independent samples T-test. RESULTS: The average diameter of the MC from the apex of the second premolar to the distal apex of the second molar, if there were no missing teeth in this segment, was 2.58 ± 0.52 mm (right) and 2.55 ± 0.54 mm (left). If there were a missing tooth in this segment, the measurements were 2.51 ± 0.79 mm (right) and 2.47 ± 0.45 mm (left). The difference between the two sides regarding the presence or absence of a missing tooth was not statistically significant. CONCLUSIONS: The precise localization of the MC related to the tooth apex and the diameter of the MC can vary in each person. CBCT indications should be considered when establishing treatment planning to avoid damaging the inferior alveolar nerve in the MC. [ABSTRACT FROM AUTHOR]

Purpose: 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). Conclusion: 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. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the positions of the mandibular foramen (MF) and mandibular canal (MC) between different skeletal classes to highlight the implications for bilateral sagittal split osteotomy (BSSO). Methods: A cross-sectional study was performed using cone-beam computed tomography on 90 patients classified into classes I, II and III. Linear measurements were performed on multiplanar reconstructions as follows: from the MF to the edge of the mandibular ramus (1), to the mandibular notch (2), to the ramus width (3) and to the occlusal plane (4); and from the MC to the alveolar crest (A), to the lower border of the mandible (B) and to the mandibular buccal cortical bone (C). Mandibular thickness (D), width (E) and height (F) of the MC were measured. Intra-class correlation coefficient (ICC) checked the reliability. Two-way ANOVA and Tukey's test were used to compare measurements and classes. Results: Linear measurements 2 presented a statistically significant difference between classes I and II. There was no statistically significant difference between the classes and measurements B, C, D, E and F. Linear measurements A were shorter in class III than in class II. Conclusions: Although most measurements suggest that the BSSO technique does not need to be modified for each skeletal class, measurements from the MF to the mandibular notch in class II and from the MC to the alveolar crest on distal of the second molars in class III could help surgeons to recognize critical regions. [ABSTRACT FROM AUTHOR]

Abstract Objectives This study aimed to assess the accuracy of a two-stage deep learning (DL) model for (1) detecting mandibular third molars (MTMs) and the mandibular canal (MC), and (2) classifying the anatomical relationship between these structures (contact/no contact) on panoramic radiographs. Method MTMs and MCs were labeled on panoramic radiographs by a calibrated examiner using bounding boxes. Each bounding box contained MTM and MC on one side. The relationship of MTMs with the MC was assessed on CBCT scans by two independent examiners without the knowledge of the condition of MTM and MC on the corresponding panoramic image, and dichotomized as contact/no contact. Data were split into training, validation, and testing sets with a ratio of 80:10:10. Faster R-CNN was used for detecting MTMs and MCs and ResNeXt for classifying their relationship. AP50 and AP75 were used as outcomes for detecting MTMs and MCs, and accuracy, precision, recall, F1-score, and the area-under-the-receiver-operating-characteristics curve (AUROC) were used to assess classification performance. The training and validation of the models were conducted using the Python programming language with the PyTorch framework. Results Three hundred eighty-seven panoramic radiographs were evaluated. MTMs were present bilaterally on 232 and unilaterally on 155 radiographs. In total, 619 images were collected which included MTMs and MCs. AP50 and AP75 indicating accuracy for detecting MTMs and MCs were 0.99 and 0.90 respectively. Classification accuracy, recall, specificity, F1-score, precision, and AUROC values were 0.85, 0.85, 0.93, 0.84, 0.86, and 0.91, respectively. Conclusion DL can detect MTMs and MCs and accurately assess their anatomical relationship on panoramic radiographs.

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.

The inferior alveolar nerve (IAN), contained within the mandibular canal (MC), is a structure prone to damage in clinical and surgical procedures on the mandible. This study aimed to analyze the MC morphology and its anatomical variants in a Chilean subpopulation using cone beam computed tomography (CBCT). In total, 342 images from patients with the following parameters were observed: 120 kV, 9 mA, field of view 12 × 9 MC, and voxel size 0.12 mm. The average length of the MC recorded a mean value of 70.493 ± 4.987 mm on the right side and 70.805 ± 5.177 mm on the left side. The location of the mental foramen (MF) was most frequently found between the mandibular first and second premolar. The greatest bone thickness was found at the level of the basilar border of the 2MPM. The root closest to the MC was distal from the mandibular second molar. The lowest thickness was in the lingual area at 1MM. The prevalence of the anterior loop (AL) (61.5%) and the retromolar canal (RC) (17.5%) showed no significant differences between men and women. The results obtained showed that the morphology of the MC in the Chilean subpopulation can vary. [ABSTRACT FROM AUTHOR]

Anatomy was initially developed out of necessity to decrease surgery complications. Over time, anatomists and surgeons have sometimes used different terms for the same anatomical structures, thus resulting in numerous discrepancies in terminology between anatomy and surgery. To avoid any confusion or misunderstanding and to better elucidate the oral anatomy terms, the Federative International Programme for Anatomical Terminology (FIPAT) organized a group of specialists on oral anatomy, Terminologia Oroanatomica (ToA) working group, composed of dentists, anatomy researchers, anatomy educators, oral and maxillofacial surgeons, and oral and maxillofacial radiologists. Within the ToA working group, major anatomical structures in the mandible, such as the mandibular canal, were focused and discussed to determine the most appropriate term, i.e., inferior alveolar canal. Although yet to be approved by the International Federation of Associations of Anatomists (IFAA), this article will preview some changes suggested by the ToA. [ABSTRACT FROM AUTHOR]

Background: The Union for International Cancer Control and American Joint Committee on Cancer tumor staging system is used globally for treatment planning. As it may be insufficient for tumor staging of lower gingival carcinomas, we proposed the mandibular canal tumor staging system. In this study, we aimed to compare the two systems for such tumor staging and to identify prognostic markers. Methods: This multicenter, retrospective study included patients with lower gingival squamous cell carcinoma who underwent radical surgery during 2001–2018. We compared survival rates (Kaplan–Meier estimator) and patient stratification according to the two systems. Results: The proposed system yielded more balanced patient stratification than the existing system. Progression in the tumor grade according to the proposed system was associated with a poorer prognosis. The 5-year overall and disease-specific survival rates for the entire cohort were 74.9% and 81.8%, respectively. Independent factors affecting overall survival were tumor stage according to the proposed system, excision margins, and number of positive nodes, whereas those affecting disease-specific survival were excision margins and number of positive nodes. Conclusions: Subsite-specific tumor classification should be used for patients with oral cancer, and our results suggest that mandibular canal tumor classification may be effective for patients with lower gingival carcinoma. [ABSTRACT FROM AUTHOR]

Purpose: 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). Conclusion: 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. [ABSTRACT FROM AUTHOR]

The article focuses on the use of diagnostic imaging in veterinary dental practice, specifically for diagnosing an impacted supernumerary tooth in a canine. Topics include the role of cone beam computed tomography (CBCT) in identifying dental abnormalities, the process of tooth extraction and surgical planning, and the importance of imaging in detecting conditions like impacted teeth and dentigerous cysts.

Aim of the study: to evaluate a reliable and user-friendly index to predict the surgical difficulty of the extractions of mesioangular impacted mandibular third molars. Material and method: Our retrospective study included 237 patients aged 16 to 40 years, with an average of 27.3. The patients were categorized into three different age groups, under 20 years, between 20 and 30 years, and between 30 and 40 years. Depending on the values of the angle of the long axis of the lower third molar with the axis of the mandibular canal we divided the cases into three groups: the first with an angle of 0°-30°, the second with an angle between 30°-60° and the last with values between 60°-90°. Another studied parameter was the operating time. Results: There were 67 patients under 20 years old (28.3%), 113 between 20 and 30 (47.7%), and (24%) between 30 and 40. 35% of the group were men, while 65% were women. The chi-square test showed a negative correlation between the duration of the surgical intervention and the molar angulation (p=0.049). There was no statistically significant correlation between the duration of the extraction and the age of the patients (p=0.941).Conclusion: Based on the results of our study, we can propose a larger one to confirm the findings of your research.

Background Dental radiology has significantly benefited from cone-beam computed tomography (CBCT) because of its compact size and low radiation exposure. Canal tracking is an important application of CBCT for determining the relationship between the inferior alveolar nerve and third molar. Usually, canal tacking is performed manually, which takes a lot of time. This study aimed to develop an artificial intelligence (AI) model to automate classification of the mandibular canal in relation to the third molar. Methods This retrospective study was conducted using 434 CBCT images. 3D slicer software was used to annotate and classify the data into lingual, buccal, and inferior categories. Two convolution neural network models, AlexNet and ResNet50, were developed to classify this relationship. The study included 262 images for training and 172 images for testing, with the model performance evaluated by sensitivity, precision, and F1 score. Results The performance of the two models was evaluated using a 3 × 3 confusion matrix, with the data categorized into 3 clases: lingual, buccal, and inferior. The mandibular canal and third molar have a close anatomical relationship, highlighting the need for precise imaging in dental and surgical settings. To accurately classify the mandibular canal in relation to the third molar, both AlexNet and ResNet50 demonstrated high accuracy, with F1 scores ranging from 0.64 to 0.92 for different classes, with accuracy of 81% and 83%, respectively, for accurately classifying the mandibular canal in relation to the third molar. Conclusion The present study developed and evaluated AI models to accurately classify and establish the relationship between the mandibular canal and third molars using CBCT images with a higher accuracy rate.

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. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to evaluate the position of the mandibular lingula (ML) in adult patients (aged between 18 and 35 years old) with different skeletal and growth patterns using cone‐beam computed tomography (CBCT). Design: Cross‐sectional. Setting: Dentistry department of University. Subjects: Subjects comprised CBCT images of 150 adult patients, including 300 rami. Methods and Materials: In total, 150 CBCT aged between 18 and 35 were selected and divided into three main groups of 50 samples based on their skeletal relationships (classes I, II and III). Patients were subdivided based on their growth pattern (vertical vs. horizontal), resulting in 25 samples per subgroup. Distances between the mandibular lingula and occlusal plane (ML‐OP), sigmoid notch (ML‐SN), external oblique ridge (ML‐EOR), internal oblique ridge (ML‐IOR), posterior border of the ramus (ML‐PBR), inferior border of the ramus (ML‐IBR), and horizontal and vertical distances to the mandibular foramen (ML‐hMF and ML‐vMF). One‐way ANOVA variance analysis was employed to compare different angle classifications, and Bonferroni analysis was used for multiple comparisons. The Student's t‐test was also used to compare growth patterns within each main group and genders within the subgroup. Results: The study revealed statistically significant differences in the position of the mandibular lingula between different angle classifications, growth patterns, and genders. Class II samples showed a more anterior position of the ML, whereas Class III samples displayed a more posterior position of the ML. Patients with horizontal growth patterns and Angle Class III had a more posteriorly positioned ML. Gender differences were observed, particularly in Class I and Class III classifications, suggesting that gender may influence the variability of ML position in these specific classifications. Conclusion: The position of the mandibular lingula showed high variability among individuals with different angle classifications, growth patterns and genders. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. 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. 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. 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. 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. [ABSTRACT FROM AUTHOR]

This article from the Romanian Journal of Oral Rehabilitation discusses the challenges of extracting impacted mandibular third molars. The researchers conducted a study to determine a reliable and user-friendly index for predicting the surgical difficulty of these extractions. They categorized patients into different age groups and measured the angle of the impacted molars with the mandibular canal. The study found a correlation between the duration of the surgical intervention and the molar angulation, but no significant correlation between extraction duration and patient age. The article emphasizes the importance of removing wisdom teeth as a preventative measure and highlights potential complications due to dentists' lack of knowledge about anatomical variations. It also provides information on different types of mandibular canals and their relationship to the inferior alveolar nerve, as well as statistics on the incidence of impacted wisdom teeth in different populations and varying rates between genders. The authors recommend further research to confirm their findings. [Extracted from the article]

Background: The application of AI algorithms for the detection of the mandibular canal in Cone Beam Computed Tomography (CBCT) holds immense promise in dentistry. Aim: This review aimed to identify the semi and fully automated algorithm to localize the mandibular canal. An extensive search was conducted and, out of which 12 articles are considered for review. The result revealed using various AI algorithms achieved better accuracy in localizing the mandibular canal with reporting sensitivity and specificity above 90 %. In conclusion, it is noted that the application of AI algorithms in dentistry can provide significant benefits like improving the accuracy of reporting.

Introduction: Impacted mandibular third molars pose challenges in dental practice, often requiring surgical intervention. This retrospective study aims to analyze the demographics, impaction patterns, and anatomical relationships of impacted mandibular third molars among Saudi patients. Methodology: Data from 722 patients visiting the Department of Maxillofacial Surgery and Diagnostic Sciences at Jizan University were retrospectively analyzed. Parameters including gender distribution, impaction types, relationship with the mandibular canal, and age demographics were evaluated based on panoramic radiographs. Results: Bilateral impaction predominated (57.59%), with mesioangular impaction being the most common (46.51%). Gender differences were noted in impaction types and relationships with the mandibular canal. Interruption of white lines of the canal was more frequent in males (70.00%). Early adulthood (20-25 years) exhibited the highest prevalence of impaction. Conclusion: The study provides insights into the demographics and characteristics of impacted mandibular third molars among Saudi patients. Gender-specific variations and age distribution underscore the importance of tailored treatment approaches and early intervention.

Background: Mandibular third molar is prone to impaction, resulting in its inability to erupt into the oral cavity. The radiographic examination is required to support the odontectomy of impacted teeth. The use of computer-aided diagnosis based on deep learning is emerging in the field of medical and dentistry with the advancement of artificial intelligence (AI) technology. This review describes the performance and prospects of deep learning for the detection, classification, and evaluation of third molar-mandibular canal relationships on panoramic radiographs. Methods: This work was conducted using three databases: PubMed, Google Scholar, and Science Direct. Following the literature selection, 49 articles were reviewed, with the 12 main articles discussed in this review. Results: Several models of deep learning are currently used for segmentation and classification of third molar impaction with or without the combination of other techniques. Deep learning has demonstrated significant diagnostic performance in identifying mandibular impacted third molars (ITM) on panoramic radiographs, with an accuracy range of 78.91% to 90.23%. Meanwhile, the accuracy of deep learning in determining the relationship between ITM and the mandibular canal (MC) ranges from 72.32% to 99%. Conclusion: Deep learning-based AI with high performance for the detection, classification, and evaluation of the relationship of ITM to the MC using panoramic radiographs has been developed over the past decade. However, deep learning must be improved using large datasets, and the evaluation of diagnostic performance for deep learning models should be aligned with medical diagnostic test protocols. Future studies involving collaboration among oral radiologists, clinicians, and computer scientists are required to identify appropriate AI development models that are accurate, efficient, and applicable to clinical services.

Background/Aim: The mandibular canal including the inferior alveolar nerve (IAN) is important in the extraction of the mandibular third molar tooth, which is one of the most frequently performed dentoalveolar surgical procedures in the mandible, and IAN paralysis is the biggest complication during this procedure. Today, deep learning, a subset of artificial intelligence, is in rapid development and has achieved significant success in the field of dentistry. Employing deep learning algorithms on CBCT images, a rare but invaluable resource, for precise mandibular canal identification heralds a significant leap forward in the success of mandibular third molar extractions, marking a promising evolution in dental practices. Material and Methods: The CBCT images of 300 patients were obtained. Labeling the mandibular canal was done and the data sets were divided into two parts: training (n=270) and test data (n=30) sets. Using the nnU-Netv2 architecture, training and validation data sets were applied to estimate and generate appropriate algorithm weight factors. The success of the model was checked with the test data set, and the obtained DICE score gave information about the success of the model. Results: DICE score indicates the overlap between labeled and predicted regions, expresses how effective the overlap area is in an entire combination. In our study, the DICE score found to accurately predict the mandibular canal was 0.768 and showed outstanding success. Conclusions: Segmentation and detection of the mandibular canal on CBCT images allows new approaches applied in dentistry and help practitioners with the diagnostic preoperative and postoperative process.

Several recent studies in dentistry and maxillofacial imaging have concentrated on the Mandibular Canal (MC) segmentation in digital dental radiographs. In this research domain, deep learning approaches have demonstrated promising outcomes. This systematic literature review (SLR) aims to comprehensively analyze and synthesize the recent advancements in applying deep learning techniques for MC segmentation in digital dental radiographs. This review encompasses studies published between 2018 and 2023, sourced from reputable databases, including PubMed, ScienceDirect, IEEE Xplore, Google Scholar, and SpringerLink. This study identified 30 primary research papers focusing on MC segmentation in digital dental radiographs. The review categorizes papers into two groups based on the digital dental radiograph type. The first group uses a 2D digital dental radiograph from a panoramic radiograph and 2D Cone Beam Computed Tomography (CBCT) scans. The second group uses 3D datasets from volumetric data from CBCT scans. The synthesized knowledge from this review is intended to guide researchers, dentists, and oral surgeons in leveraging deep learning advancements in MC segmentation for oral and maxillofacial surgery. Prior studies have faced challenges, including limited public datasets, variations in MC anatomy, time consumption and observer variability in MC annotation, complexities in deep learning models, and lack of practical implementation. To overcome these challenges, it is suggested that more public datasets be collaboratively created and shared within the research community, focusing on handling anatomy variability, improving digital dental radiograph quality, streamlining annotation processes through automated tools, and simplifying deep learning models for practical implementation.

Mandibular incisive canal (MIC) and related mental foramen (MF) and anterior loop (AL) morphometrics are important landmarks in medical and dental clinical applications. The main aim of this retrospective study to determine the morphometry of the mandibular incisive canal (MIC) in a Jordanian population and to propose a new shape-pattern classification of the MIC. In addition, MF and AL morphometrics were determined. Carestream 3D imaging software was used on 100 Cone-Beam Computed Tomography (CBCT) of a Jordanian population to determine the MF, AL and MIC morphometrics. The detection prevalence of the MIC was 96 %. The right and left MIC showed four distinct line patterns, proposed for the first time in this paper. The line-patterns were angular (L-line), straight (I-line), curved (V-line) and wavy (W-line), with a prevalence of 41 %, 19 %, 25.5 %, and 10.5 %, respectively. MF was detected in all mandibles with a round shape in 58 % of the images. The most common horizontal and vertical positions of the MF were H4 and H3 (73.5 %) and V3 and V2 (95 %), respectively. An accessory MF was detected in 14.5 % of the samples and was more prevalent in males and on the right side. AL was detected in 92.5 % of the samples and exhibited a pattern prevalence of 25.5 %, 40 % and 27 % for types I, II and III, respectively. Results revealed that asymmetry and gender differences between right and left MIC, MF, AL and AMF was seen in patient's mandibles. In conclusion, this is the first study to propose and show that Mandibular incisive canal exhibits four potential line patterns (L, I, V and W lines patterns). Gender and ethnic variations of the mandibular canal landmarks morphometrics of both right and left hemi-mandible are important to be acknowledged in learning anatomy and when planning or performing dental and medical procedures. [ABSTRACT FROM AUTHOR]

Mandibular third molar is prone to impaction, resulting in its inability to erupt into the oral cavity. The radiographic examination is required to support the odontectomy of impacted teeth. The use of computer-aided diagnosis based on deep learning is emerging in the field of medical and dentistry with the advancement of artificial intelligence (AI) technology. This review describes the performance and prospects of deep learning for the detection, classification, and evaluation of third molar-mandibular canal relationships on panoramic radiographs. This work was conducted using three databases: PubMed, Google Scholar, and Science Direct. Following the literature selection, 49 articles were reviewed, with the 12 main articles discussed in this review. Several models of deep learning are currently used for segmentation and classification of third molar impaction with or without the combination of other techniques. Deep learning has demonstrated significant diagnostic performance in identifying mandibular impacted third molars (ITM) on panoramic radiographs, with an accuracy range of 78.91% to 90.23%. Meanwhile, the accuracy of deep learning in determining the relationship between ITM and the mandibular canal (MC) ranges from 72.32% to 99%. Deep learning-based AI with high performance for the detection, classification, and evaluation of the relationship of ITM to the MC using panoramic radiographs has been developed over the past decade. However, deep learning must be improved using large datasets, and the evaluation of diagnostic performance for deep learning models should be aligned with medical diagnostic test protocols. Future studies involving collaboration among oral radiologists, clinicians, and computer scientists are required to identify appropriate AI development models that are accurate, efficient, and applicable to clinical services. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to propose a deep-learning model for the detection of the mandibular canal on dental panoramic radiographs. Materials and Methods: A total of 2,100 panoramic radiographs (PANs) were collected from 3 different machines: RAYSCAN Alpha (n=700, PAN A), OP-100 (n=700, PAN B), and CS8100 (n=700, PAN C). Initially, an oral and maxillofacial radiologist coarsely annotated the mandibular canals. For deep learning analysis, convolutional neural networks (CNNs) utilizing U-Net architecture were employed for automated canal segmentation. Seven independent networks were trained using training sets representing all possible combinations of the 3 groups. These networks were then assessed using a hold-out test dataset. Results: Among the 7 networks evaluated, the network trained with all 3 available groups achieved an average precision of 90.6%, a recall of 87.4%, and a Dice similarity coefficient (DSC) of 88.9%. The 3 networks trained using each of the 3 possible 2-group combinations also demonstrated reliable performance for mandibular canal segmentation, as follows: 1) PAN A and B exhibited a mean DSC of 87.9%, 2) PAN A and C displayed a mean DSC of 87.8%, and 3) PAN B and C demonstrated a mean DSC of 88.4%. Conclusion: This multi-device study indicated that the examined CNN-based deep learning approach can achieve excellent canal segmentation performance, with a DSC exceeding 88%. Furthermore, the study highlighted the importance of considering the characteristics of panoramic radiographs when developing a robust deep-learning network, rather than depending solely on the size of the dataset. [ABSTRACT FROM AUTHOR]

(1) Background: This study assessed the spatial position and anatomical features associated with impacted third molars through a map-reading strategy employing cone-beam computed tomography (CBCT). (2) Methods: The positioning of impacted third molars on CBCT was assessed using Winter's and Pell and Gregory's classifications. External root resorption in mandibular second molars was categorized according to Herman's classification. Additionally, the relationship between the mandibular third molar root apex and the mandibular canal was examined. Comparative statistical analysis was conducted using Fisher's exact test, with a significance level considered as 5%. (3) Results: The results indicated that, based on Winter's classification, 48.06 % of impacted teeth were positioned mesioangularly. Employing Pell and Gregory's classification, 43.22% of the impacted molars fell into positions B and C, with 54.2% classified as Class II. A notable 69.7% of teeth exhibited no contact between the root apex and the mandibular canal, and external root resorption in the distal aspect of the second molar was absent in 88.7% of cases. (4) Conclusions: Utilizing the map-reading strategy with CBCT scans to assess the anatomical positions and characteristics of impacted third molars enhances professional confidence and sets a standard for quality and safety in the surgical procedure for patients. [ABSTRACT FROM AUTHOR]

Aim: We aim to evaluate the diagnostic performance of a deep learning (DL) system for determining the three‐dimensional contact status between the mandibular third molar and canal on panoramic radiography images. Methods: A total of 800 image patches consisting of 400 patches of low‐ and high‐risk groups, each verified by computed tomography (CT) or cone‐beam CT for dental use, were cropped from downloaded panoramic images and input into a DL system. Seven hundred of these patches (350 high‐risk and 350 low‐risk group patches) were randomly assigned to the training and validation datasets, and 100 (50 high‐risk and 50 low‐risk group patches) were assigned to the test datasets. Using data augmentation for the training datasets, the training process was carried out twice. Receiver operating characteristic (ROC) analysis was used to compare the performance of two kinds of observers (residents and radiologists) with the same test images. The interclass correlation coefficients (ICCs) were determined to evaluate the diagnostic consistency. Results: The area under the ROC curves (AUCs) of the DL model, residents, and radiologists were 0.85, 0.55, and 0.81, respectively. Significant differences were observed between the DL model and residents, and between the residents and radiologists. The ICCs of the DL model, residents, and radiologists were 0.69, 0.19, and 0.54, respectively. Conclusions: The DL model has potential for use in diagnostic support in the evaluation of the three‐dimensional contact status between the mandibular third molar and canal on panoramic images. [ABSTRACT FROM AUTHOR]

Background: Dynamic advances in dentistry, especially in implantology has inspired researchers to carry out many studies investigating the topography of the mandibular canal and its ethnic differences. The aim of the study was a comparative analysis of variations in the position and topography of the mandibular canal based on radiographic images of human mandibles originating from modern and medieval skulls. Materials and methods: Morphometric examination of 126 radiographs of skulls (92 modern and 34 medieval skulls) was included. The age and sex of individuals were determined based on the morphology of the skull, the obliteration of cranial sutures, and the degree of tooth wear. To define the topography of the mandibular canal on X-ray images, we took 8 anthropometric measurements. Results: We observed significant differences in several parameters. The distance between the base of the mandible and the bottom of the mandibular canal, the distance between the top of the mandibular canal and the crest of the alveolar arch, and the height of the mandibular body. Significant asymmetry was found for two parameters of mandibles from modern skulls: the distance between the top of the mandibular canal and the crest of the alveolar arch at the level of the second molar (p < 0.05), and the distance between the mandibular foramen and the margin of the anterior mandibular ramus (p < 0.007). There were no significant differences between measurements taken on the right and left sides of the medieval skulls. Conclusions: Our study revealed differences in the position of the mandibular canal between modern and medieval skulls, confirming the presence of geographical and chronological differences between populations. Knowledge of variability in the position of the mandibular canal between different local populations is fundamental for the correct interpretation of findings from diagnostic radiological studies used in dental practice and in forensic odontology or analysis of archaeological bone materials. [ABSTRACT FROM AUTHOR]

Background and Aim: Dentists should be aware of the position and anatomical path of the inferior alveolar canal (IAC). The aim of this study was to investigate the position and anatomical path of the IAC on cone-beam computed tomography (CBCT) images in an Iranian population. Materials and Methods: This retrospective study included 150 CBCT images. The distance of the IAC from the buccal and lingual cortex in the alignment of teeth 4 to 7 and the emerging pattern of the inferior alveolar nerve (IAN) from the mental foramen were assessed. Using SPSS version 22 software, the role of age, gender, and side of the jaw in the investigated parameters were evaluated by Pearson correlation, independent and paired samples t test, and chi-square test. Results: The most frequent emerging pattern of the IAN was "sharp turn with 90° angle" (44.7%). The average distance of the IAC from the buccal cortex of the mandible, unlike the lingual cortex, increased in the alignment of teeth 4 to 7 in both genders (P0.05). Conclusion: Although the distance of the IAC from cortex was not related to age, it was greater in the men than women. Considering the variations in the IAC path and the IAN emerging patterns, CBCT radiography is suggested in doubtful cases.

Abstract Objective To observe the three-dimensional positional relationship between impacted mandibular third molars (IMTMs) and mandibular canal close contacts using cone beam computed tomography (CBCT). Methods A total of 101 patients with IMTMs were selected who met the diagnostic criteria for 142 teeth (no bone wall imaging area between IMTMs and the mandibular canal, a high-density bone cortical imaging area only, or a ≦1 mm bone imaging area). The parameters of the rotating CBCT anode were set as follows: 110 kV, 40–50 mA; the focal point and exposure field were set as 0.3 mmh and a high-resolution zoom, respectively; the exposure time and image layer thickness were set as 5.4 s and 0.25 mm. Three-dimensional reconstruction was performed, and the position of the mandibular canal through the IMTM area was observed continuously from the coronal, horizontal and sagittal planes. Results We found that the mandibular canal was interrupted below the third molar (TM) in 85 cases, accounting for 59.86% of all cases. The mandibular canal was located below the buccal and lingual curvatures in 33 and 19 cases, respectively, accounting for 23.23% and 19%. In addition, a small number of mandibular canals were also located on the buccal side of the mandibular molars (2.82%). We also found one case of direct insertion of the mandibular third molar (MTM) into the mandibular canal. In addition, the mandibular canal passed through the IMTM region with 125 close contacts at the roots (88.03%); 14 mandibular canals were in contact with all teeth and 3 were in contact with the crown. Conclusion The use of CBCT can provide a dynamic and comprehensive understanding of the three-dimensional positional relationship of the mandibular alveolar nerve canal passing through the IMTM area, providing a high clinical reference value when extracting IMTMs and reducing the risk of injury to the inferior alveolar nerve.

The inferior alveolar nerve (IAN), contained within the mandibular canal (MC), is a structure prone to damage in clinical and surgical procedures on the mandible. This study aimed to analyze the MC morphology and its anatomical variants in a Chilean subpopulation using cone beam computed tomography (CBCT). In total, 342 images from patients with the following parameters were observed: 120 kV, 9 mA, field of view 12 × 9 MC, and voxel size 0.12 mm. The average length of the MC recorded a mean value of 70.493 ± 4.987 mm on the right side and 70.805 ± 5.177 mm on the left side. The location of the mental foramen (MF) was most frequently found between the mandibular first and second premolar. The greatest bone thickness was found at the level of the basilar border of the 2MPM. The root closest to the MC was distal from the mandibular second molar. The lowest thickness was in the lingual area at 1MM. The prevalence of the anterior loop (AL) (61.5%) and the retromolar canal (RC) (17.5%) showed no significant differences between men and women. The results obtained showed that the morphology of the MC in the Chilean subpopulation can vary.

AMAÇ: Bu çalışmada; 2018-2019 yılları arasında Gazi Üniversitesi Diş Hekimliği Fakültesi Ağız, Diş ve Çene Cerrahisi Anabilim Dalı’na başvuran hastaların gömülü üçüncü molar dişlerinin; Winter, Archer ile Pell ve Gregory sınıflandırmalarına göre pozisyonlarının, sürme seviyelerinin ve gömüklülük durumlarının retrospektif olarak değerlendirilmesi amaçlanmıştır. GEREÇ VE YÖNTEM: Yaş ortalaması 25.78 olan 1548 hastadan alınan panoramik filmlerde tespit edilen 5523 gömülü üçüncü molar dişi, yaş ve cinsiyet özelliklerine göre değerlendirilmiştir. Tüm gömülü üçüncü molar dişlerin pozisyonlarına göre sınıflandırılması yapılmış ve elde edilen sonuçlar literatür ile karşılaştırılmıştır. BULGULAR: Analiz sonuçları doğrultusunda; cinsiyet ile Winter sınıflamasına göre 18, 38 ve 48 nolu dişlerin pozisyonları arasında, cinsiyet ile Archer sınıflamasına göre 18, 28 ve 48 nolu dişlerin sürme seviyeleri arasında; cinsiyet ve 38-48 nolu gömülü dişlerin mandibular kanal ile olan ilişkisi arasında istatistiksel olarak anlamlı bir ilişki olduğu (p=0.000), cinsiyet ile Pell & Gregory sınıflamasına göre 38-48 nolu gömülü dişlerin M3 mesafesi arasında istatistiksel olarak anlamlı bir ilişki olmadığı tespit edilmiştir (p>0.05). SONUÇ: Gömülü üçüncü molar dişlerin çekiminde bazı riskler bulunmaktadır. Bu riskler dişlerin gömüklülük durumundan ve pozisyonlarından kaynaklanabilir. Özellikle gömülü alt üçüncü molar diş köklerinin mandibular kanal ile olan ilişkisi açısından olası risklerin tespit edilerek en aza indirilmesi amacıyla preoperatif değerlendirme yapılması elzemdir.

Abstract Background Endodontic microsurgery has yielded highly successful outcomes in preserving teeth with persistent or recurrent cases of periapical periodontitis that could not be successfully treated by nonsurgical endodontic approaches. To avoid complications in conditions in which periapical lesions invade anatomical structures such as the nasopalatine nerve tube and mandibular canal, selective curettage has been proposed as an alternative choice of complete curettage in surgery. Case presentation The 8 cases reported herein had undergone root canal treatment and/or retreatment but still presented with symptoms, such as recurring sinus tracts and persistent dull pain. The radiographic examination indicated a large area of radiolucency that was associated with the tooth and had invaded adjacent critical anatomical structures. The patients opted for selective curettage via endodontic microsurgery, and the lesions were histologically confirmed as periapical cysts or granulomas. The follow-up results for one year or more indicated that the affected teeth were clinically asymptomatic and exhibited complete or incomplete healing radiographically. Conclusion This case series provides clinical evidence for the feasibility of selective curettage in endodontic microsurgery, which can avoid complications caused by damage to the adjacent critical anatomical structures.

Understanding the clinical anatomy of the head is essential for performing proper inferior alveolar nerve (IAN) block anesthesia to facilitate invasive dental procedures in camels. However, osteometric data related to the IAN in camels are lacking. This study was carried out to accurately locate the mandibular foramen (MF) and the course of the IAN in the camel head and to establish an approach for its localization in clinical practice. To achieve these aims, eight osteometric measurements were used to determine the location of the MF in relation to its surrounding structures in six cadaveric skulls of adult camels. Four camel heads were dissected, and the course of the IAN inside the mandibular canal was studied. In addition, four heads were used as a trial for the extraoral approach to the IAN block using contrast radiographs based on established metric indices. Dissection of the four camel heads revealed that the MF was located near the intersection of two lines passing through the occlusal surface of the mandibular cheek teeth and at the midpoint of the zygomatic process of the temporal bone. Significant differences were not observed between the right and left mandibles. Successful deposition of the contrast medium near the MF was observed in all examined specimens. This study reports a new, simple approach to reaching the IAN at the MF. However, further clinical validation of the proposed technique is required. [ABSTRACT FROM AUTHOR]

Introduction: Mandibular osteotomies in facial asymmetry are complicated by the abnormal position and course of inferior alveolar nerve. This manuscript aims to evaluate the possible variations in the preoperative positions of mandibular canal and mandibular foramen in patients with mandibular asymmetry due to condylar hyperplasia or condylar hypoplasia. Materials & Methods: This study included 15 patients with mandibular asymmetry due to condylar hyperplasia or condylar hypoplasia for which bilateral sagittal split osteotomy (BSSO) was performed as a corrective procedure. The presence/absence and extent of postoperative neurosensory deficiency was recorded subjectively and objectively. The measurements were done using multiplanar reconstruction (MPR) of three-dimensional radiographic imaging and were compared to normal subjects. Discussion: The results revealed that the mandibular canal was closer to the buccal cortex on the affected side and the inferior border on both sides in the region of second molar in condylar hyperplasia. In condylar hypoplasia, the canal was nearer to the inferior border and the alveolar crest in relation to second and third molars respectively on the affected and contralateral sides.The mandibular foramen was also more superior to the occlusal plane on both sides in both condylar hyperplasia and hypoplasia. Conclusion: Based on the study outcomes, the authors propose that assessment of the positions of mandibular canal and mandibular foramen is crucial to avoid postoperative neurosensory deficiencies. [ABSTRACT FROM AUTHOR]

Objective: To observe the three-dimensional positional relationship between impacted mandibular third molars (IMTMs) and mandibular canal close contacts using cone beam computed tomography (CBCT). Methods: A total of 101 patients with IMTMs were selected who met the diagnostic criteria for 142 teeth (no bone wall imaging area between IMTMs and the mandibular canal, a high-density bone cortical imaging area only, or a ≦1 mm bone imaging area). The parameters of the rotating CBCT anode were set as follows: 110 kV, 40–50 mA; the focal point and exposure field were set as 0.3 mmh and a high-resolution zoom, respectively; the exposure time and image layer thickness were set as 5.4 s and 0.25 mm. Three-dimensional reconstruction was performed, and the position of the mandibular canal through the IMTM area was observed continuously from the coronal, horizontal and sagittal planes. Results: We found that the mandibular canal was interrupted below the third molar (TM) in 85 cases, accounting for 59.86% of all cases. The mandibular canal was located below the buccal and lingual curvatures in 33 and 19 cases, respectively, accounting for 23.23% and 19%. In addition, a small number of mandibular canals were also located on the buccal side of the mandibular molars (2.82%). We also found one case of direct insertion of the mandibular third molar (MTM) into the mandibular canal. In addition, the mandibular canal passed through the IMTM region with 125 close contacts at the roots (88.03%); 14 mandibular canals were in contact with all teeth and 3 were in contact with the crown. Conclusion: The use of CBCT can provide a dynamic and comprehensive understanding of the three-dimensional positional relationship of the mandibular alveolar nerve canal passing through the IMTM area, providing a high clinical reference value when extracting IMTMs and reducing the risk of injury to the inferior alveolar nerve. [ABSTRACT FROM AUTHOR]

Purpose: This retrospective study aimed to determine the prevalence and morphological characteristics of accessory mandibular canals (AMCs) in an eastern Chinese population to provide clinical guidance for reducing intraoperative and postoperative complications. Methods: Cone beam computed tomography (CBCT) scans of 300 Chinese patients were used to identify AMCs according to a modification of Naitoh's classification. The length of the branch (L0) and the upper and lower angles between the branch and mandibular canal were measured on sagittal images. Additionally, the branches were divided into narrow or wide types by calculating the ratio of the branch diameter to the main canal diameter. The location of the bifurcation point was characterized by measuring its distance to the buccal wall of the mandible (L1), lingual wall of the mandible (L2) and alveolar ridge (L3). Results: The prevalence rate of AMCs was 40.7% (95% CI: 35.1–46.3), and the most common type was the retromolar canal, followed by the forward canal, dental canal, trifid mandibular canals (TMCs) or others, inferior canal and buccolingual canal. Twenty-one cases of multiple branches with unusual patterns were observed in the study. The average values of L0, L1, L2 and L3 were 15.05 ± 0.63 mm, 5.79 ± 0.14 mm, 4.40 ± 0.18 mm and 14.61 ± 0.31 mm, respectively. The mean upper angle and lower angle were 141.59° ± 2.44° and 50.64° ± 2.57°, respectively. Approximately 20.8% of the branches were defined as wide type, and no statistical significance was found between different types. Conclusion: AMCs are not rare anatomic variations of the mandibular canal in the eastern Chinese population; thus, CBCT examination is highly recommended for precise evaluation before surgeries involving the mandibles. [ABSTRACT FROM AUTHOR]

Objectives: To develop and validate a novel artificial intelligence (AI) tool for automated segmentation of mandibular incisive canal on cone beam computed tomography (CBCT) scans. Methods: After ethical approval, a data set of 200 CBCT scans were selected and categorized into training (160), validation (20), and test (20) sets. CBCT scans were imported into Virtual Patient Creator and ground truth for training and validation were manually segmented by three oral radiologists in multiplanar reconstructions. Intra- and interobserver analysis for human segmentation variability was performed on 20% of the data set. Segmentations were imported into Mimics for standardization. Resulting files were imported to 3-Matic for analysis using surface- and voxel-based methods. Evaluation metrics involved time efficiency, analysis metrics including Dice Similarity Coefficient (DSC), Intersection over Union (IoU), Root mean square error (RMSE), precision, recall, accuracy, and consistency. These values were calculated considering AI-based segmentation and refined-AI segmentation compared to manual segmentation. Results: Average time for AI-based segmentation, refined-AI segmentation and manual segmentation was 00:10, 08:09, and 47:18 (284-fold time reduction). AI-based segmentation showed mean values of DSC 0.873, IoU 0.775, RMSE 0.256mm, precision 0.837 and recall 0.890 while refined-AI segmentation provided DSC 0.876, IoU 0.781, RMSE 0.267mm, precision 0. 852 and recall 0.902 with the accuracy of 0.998 for both methods. The consistency was one for AI-based segmentation and 0.910 for manual segmentation. Conclusions: An innovative AI-tool for automated segmentation of mandibular incisive canal on CBCT scans was proofed to be accurate, time efficient, and highly consistent, serving pre-surgical planning. [ABSTRACT FROM AUTHOR]

Background and Objectives: The third molar has the most diverse root position among all teeth. One of the inherent risks of extracting this tooth in the mandible is damage to the inferior alveolar nerve. Due to the difference in the placement angle and the depth of the impacted teeth, the possibility of damage to the inferior alveolar nerve is more in some patients. Considering the different variations in the position of the teeth, the aim of this study was to report and describe the position of the third molar and its proximity to the mandibular canal in a dry mandible. Case report: At the time of evaluation of the mandibles in the Anatomy Museum, an unusual case involving the horizontal position of the left third molar was observed. The length of the tooth from the apex of the cusps to the end of the root was 21 mm and the thickness of the upper part of the tooth was 9 mm. Also, the distance between the root of the tooth and the tip of the Lingula was 19 mm. Based on the data obtained from the radiographic image, the distance between the tooth root and the mandibular canal was 2 mm. Conclusion: Knowledge of the anatomical variations of the third molar will be useful in surgeries related to this area and to prevent damage to the inferior alveolar nerve. Furthermore, this report is important since the position of this tooth and the proximity of its root to the mandibular canal have not been documented on the bone sample so far. [ABSTRACT FROM AUTHOR]