Mandibular Canal Research Articles

Prevalence of middle mesial canals in mandibular first molars in coastal Andhra population – A Cone beam computed tomography study

Introduction: Recognition of variations in root canal anatomy is an essential prerequisite for successful endodontic diagnosis and treatment. Most of the endodontic failures result from missed canals. The mandibular first molar has the most complex root canal system and a high percentage of treatment failures are due to the impossibility of locating, instrumenting and obturating the middle mesial canal (MM). There are very few studies available regarding the incidence of MM canal in mandibular first molar. The present study evaluated the prevalence of the middle mesial canals in mandibular first molars using cone beam computed tomography (CBCT). Materials and Methodology: CBCT images of mandibular first molars were collected from patients (n= 100) who had undergone CBCT imaging. The images were analyzed and the prevalence of MM canals were calculated. Results: The data were analysed using descriptive statistics. In total of 100 patients, 60 were women and 40 were men, with age range 11-60 years old. 21 MM canals were identified in this study. In this, 11 were female and 10 were male. The prevalence of the MM canal in mandibular first molar MM canals were identified in 21% (21/100). Conclusion: Within the limitations of the study, it can be concluded that though advanced techniques like troughing and magnification help in finding and negotiating MM canals, 3D radiographies like CBCT can be as used as valuable adjunct to the above mentioned methods. When these canals are treated, the success rate of the endodontic treatment would definitely increase. Clinical studies with long-term follow-ups are needed to determine the effect of preparation of MM canals on the outcome of nonsurgical endodontic treatment in mandibular first molars. Keywords: Cone Beam Computed Tomography, Mandibular First Molar, Middle Mesial Canal, Prevalence.

Morphometric Analysis of the Midline Mandibular Lingual Canal and Mandibular Lingual Foramina: A Cone Beam Computed Tomography (CBCT) Evaluation.

This study aimed to evaluate the midline mandibular lingual canals and foramina and their anatomic variations using CBCT scans. This study used retrospective analysis. A total of 320 CBCT scans were used to evaluate the study parameters, which comprised the presence or absence of the mandibular lingual foramen (MLF)/mandibular lingual canal (MLC) and its category, the distance between the buccal cortex and the start of the MLC, the distance between the inferior border of the mandible and the superior border of the foramen at its lingual and buccal terminals. The length and diameter of each canal at its lingual and buccal terminals. MLC was found in all included CBCT scans. Out of 320 included CBCT scans, a single canal was represented by 30.9%, double canals (Supra with Infra -spinosum) configuration appeared in 54.7%, and triple canals (Supra-Inter-Infra) represented 14.7%. The supraspinosum canals averaged 5.81 ± 2.08 mm in length and 0.87 ± 0.30 mm in diameter at the lingual terminal. In terms of the number of canals, there was a significant difference between men and women (p ≤ 0.001), with 60% of the men in the sample having double canals and 43.1% of the women having single canals. Moreover, the male gender had a higher prevalence of triple canals (21.3% vs. 8.1%) than females. Males and females were distributed equally among the supraspinosum canals, with no statistically significant difference (p ≤ 0.7). A considerable increase in the finding of interspinosum and infraspinosum canals was seen in the male sample (p ≤ 0.001). midline mandibular canals were found in all investigated CBCTs of the sample of both sexes; however, the anatomy and location of the MLF and canals varied significantly among the Saudi population.

Dual-Stage Deeply Supervised Attention-Based Convolutional Neural Networks for Mandibular Canal Segmentation in CBCT Scans.

Accurate segmentation of mandibular canals in lower jaws is important in dental implantology. Medical experts manually determine the implant position and dimensions from 3D CT images to avoid damaging the mandibular nerve inside the canal. In this paper, we propose a novel dual-stage deep learning-based scheme for the automatic segmentation of the mandibular canal. In particular, we first enhance the CBCT scans by employing the novel histogram-based dynamic windowing scheme, which improves the visibility of mandibular canals. After enhancement, we designed 3D deeply supervised attention UNet architecture for localizing the Volumes Of Interest (VOIs), which contain the mandibular canals (i.e., left and right canals). Finally, we employed the Multi-Scale input Residual UNet (MSiR-UNet) architecture to segment the mandibular canals using VOIs accurately. The proposed method has been rigorously evaluated on 500 and 15 CBCT scans from our dataset and from the public dataset, respectively. The results demonstrate that our technique improves the existing performance of mandibular canal segmentation to a clinically acceptable range. Moreover, it is robust against the types of CBCT scans in terms of field of view.

New host and first description of the male of Colobomatus stelliferi Pombo, Turra, Paschoal & Luque, 2015 (Copepoda: Philichthyidae), parasite of Umbrina canosai Berg, 1895 (Actinopterygii: Sciaenidae) off Brazil: improving the taxonomic knowledge pertaining to Colobomatus spp.

The present study provides new host and first description of the male of Colobomatus stelliferi Pombo, Turra, Paschoal & Luque, 2015 (Copepoda, Philichthyidae), collected from the mandibular canals of the Argentine croaker Umbrina canosai Berg, off the State of Rio de Janeiro, Brazil. Four out of nine fish analyzed (prevalence 44.4%) were parasitized by C. stelliferi and showed a mean intensity of 2.5 (range 2-3, standard deviation 1.25). Adult males of C. stelliferi can be differentiated from their closest congeners based on the combination of the following characters: maxilliped with naked basal segment and small apical spine, the presence of two elements on the second endopodal segment of the antenna, and the presence of leg 4. This parasitic copepod is seemingly host-specific to fish of the family Sciaenidae and its occurrence is restricted to the Brazilian coast. The present results contribute to our knowledge of the biology of C. stelliferi and of the parasitic copepod fauna from Brazil.

Comparison of deep learning segmentation and multigrader-annotated mandibular canals of multicenter CBCT scans

Deep learning approach has been demonstrated to automatically segment the bilateral mandibular canals from CBCT scans, yet systematic studies of its clinical and technical validation are scarce. To validate the mandibular canal localization accuracy of a deep learning system (DLS) we trained it with 982 CBCT scans and evaluated using 150 scans of five scanners from clinical workflow patients of European and Southeast Asian Institutes, annotated by four radiologists. The interobserver variability was compared to the variability between the DLS and the radiologists. In addition, the generalisation of DLS to CBCT scans from scanners not used in the training data was examined to evaluate its out-of-distribution performance. The DLS had a statistically significant difference (p < 0.001) with lower variability to the radiologists with 0.74 mm than the interobserver variability of 0.77 mm and generalised to new devices with 0.63 mm, 0.67 mm and 0.87 mm (p < 0.001). For the radiologists’ consensus segmentation, used as a gold standard, the DLS showed a symmetric mean curve distance of 0.39 mm, which was statistically significantly different (p < 0.001) compared to those of the individual radiologists with values of 0.62 mm, 0.55 mm, 0.47 mm, and 0.42 mm. These results show promise towards integration of DLS into clinical workflow to reduce time-consuming and labour-intensive manual tasks in implantology.

Clinical and Radiological Correlation with Surgery of Third Mandibular Impacted Molars

Overview :Tooth extraction is one of the most common procedures in dentistry and oral maxillofacial medicine. Vigilant investigation of the condition and an accurate preoperative assessment, planning, evaluating indications and contraindications, is needed in all the cases. The objective : The aim of this study is to evaluate the role of radiographic examinations in diagnosis and surgery planning of lower third molar extraction. Materials and methods : Review of literature; on pubmed, medline, embase, sciencedirect, and the Cochrane library, using key words of impacted molars, third molars, mandibula, alveolar, dentistry, oral maxillofacial. Results: During dental and oral maxillofacial daily clinical practice is quite often to face impacted third lower molars, a condition that can lead to a close relation with important anatomical structures. Radiographic examinations are useful in the diagnosis and subsequently in the surgery planning and must submit to principle of justification and optimization. Intraoral radiography and orthopantomography hardly permit to evaluate the buccal or lingual position of the inferior alveolar nerve so to better predict the risk of complications. There are some radiographic signs that suggest the necessity to perform a more accurate radiographic investigation that provides a three-dimensional view of the images. The three-dimensional radiographic methods, by means of sagittal, frontal and axial views, are used to determine anatomical location, proximity, and possible contact of the third molar with the mandibular canal, blood vessels and nerves branches. The beginning of Cone Beam Computed Tomography (CBCT) has reduced the equipment cost but then again above all the radiation exposure for the patients. Conclusions: In the past few years three-dimensional reconstructive technologies were introduced: besides advantages, in addition to the potential benefit in the reduction of complications related to the patient, also resides in the different approach of the surgeon: stress and duration of dental and oral maxillofacial surgical procedures significantly is reduced because the respective medical specialist know exactly the position of anatomical structures. This information will help the surgeon to determine a possible post-operative paresthesia and plan the better surgical technique. Keywords : Impacted molars, third molar, surgery, inferior alveolar nerve, OPT, CBCT DOI: 10.7176/ALST/95-04 Publication date: November 30 th 2022

PARTICULAR FEATURES OF ROOT CANAL FILLING IN TEETH WITH RESORBED APICAL OPENING NEAR THE MANDIBULAR CANAL

When filling root canals of teeth with apical resorption near the mandibular canal, there is a risk that the material will go beyond the apex into the region of mandibular canal, which can lead to serious damage to the innervation of this area. In most cases, modern approaches and technologies in endodontics allow to achieve the formation of dentinal plug in the resorption area, thus minimizing the risk of traumatization of the patient.&#x0D; Background. Improving efficiency of endodontic treatment of teeth with apical resorption in the region of mandibular canal.&#x0D; Materials and methods. 56 patients aged between 18 and 45 years were examined. All patients had clinical signs of mandibular endodontic treatment failure with a dark radiolucent focus in the region of the apex, which bordered the mandibular canal. Radiological indicators and quality of obturation were assessed on the basis of CBCT, the presence of dentinal bridge was assessed visually using a dental microscope and an apical hermetic test. The results were evaluated after 4, 6, 12, and 24 months.&#x0D; Results. After 16 weeks of treatment, more than 70% of apical barrier formation occurred in groups 1 and 2, which allowed us to perform a quality permanent obturation without excessive risks of complications.&#x0D; Conclusion. The use of a dental microscope in conjunction with modern endodontic techniques in the treatment of teeth with apical resorption can significantly reduce the treatment time, thereby improving the quality of treatment of patients with this pathology.

Radiografía panorámica y tomografía computarizada de haz cónico para medir distancias entre ápices radiculares y estructuras anatómicas

Aim: To compare the accuracy of the panoramic radiography with cone-beam computed tomography (CBCT) scans in measuring the distances between root apexes and the adjacent anatomical structures including the maxillary sinus and the mandibular canal. Material and Methods: A total of 200 CBCT scans (100 maxillary and 100 mandibular) from patients who also had corresponding panoramic radiography were selected. Linear measurements (in mm) presenting centralized image were made between the apexes of the maxillary teeth and the inferior wall of the maxillary sinus, and between the apexes of the mandibular teeth and the superior border of the mandibular canal by using specific software for panoramic radiography and the measurements on the coronal sections in CBCT scans. Data were submitted to inferential statistical analysis and Student’s t-test for comparison between measurements. Results: CBCT scans were significantly more accurate than panoramic radiography to measure the distances between the apexes of the maxillary teeth and the inferior wall of the maxillary sinus (p&lt;0.05) and between the apexes of the mandibular teeth and the superior border of the mandibular canal or mental foramen (p&lt;0.05). Conclusion: CBCT scans present more accurate measurements than panoramic radiography.

Radiographic analysis of the anterior mandible and its anatomical variations using cone-beam computed tomography.

The anterior loop, the mandibular incisive canal, and the lingual symphyseal foramen are important structures in the anterior mandible. The purpose of this study was to assess the prevalence of these structures using CBCT. A total of 170 projections were analyzed in different sectional planes. The study analyzed the prevalence and extension of the anterior loop and the prevalence of both the mandibular incisive canal and the lingual symphyseal foramen by using the GALAXIS software by Sirona. In 98.2 % (n = 167) a lingual symphyseal foramen was detected. An anterior loop was present in 31.2% (n = 53) with statistically significant higher detection rate in younger patients (P = .001). The median length was 1.26 mm (range 0.53-3.70 mm). No statistically significant differences regarding patient side or sex were found in either case. In 72.4% (n = 123) a mandibular incisive canal was detected. There was a statistically significant dependence of the mandibular incisive canal on patient sex (P = .007): female patients had a mandibular incisive canal significantly more often than male patients. Among male patients a significant difference of the mandibular incisive canal regarding the mandibular side (P = .031) was found; it was significantly less frequent on the right than on the left side. Anterior loop, mandibular incisive canal, and lingual symphyseal foramen are often present. Furthermore, the anatomical, neurovascular variability in the interforaminal area of the mandible emphasizes the importance of 3D imaging like CBCT in preoperative assessment, and confirms that a general safe zone should not solely be relied upon when performing surgery in this region.

Paresthesia of the inferior alveolar nerve caused by periapical pathology: case report

Paresthesia in the chin area may not always be caused by a neurological condition. Sometimes persistent and prolonged treatment of the trigeminal nerve for neuralgia, does not have a positive result. One cause of mandibular numbness may be caused by compression on the mandibular canal by an odontogenic cyst.Aim. To demonstrate the clinical symptomatology and radiological signs of mandibular nerve damage in a 48-year-old patient who underwent re-treatment of the lower left seventh tooth in 2 visits with long-term clinical and radiological follow-up.

Evaluation of the Spatial Relationship of Impacted Mandibular Third Molar to Mandibular Canal Using CBCT

Introduction: Impaction is defined as the “lack of eruption of a tooth in the oral cavity within the time and physiological limits of the normal eruption process.” The prevalence of damage to the inferior alveolar nerve during surgical extraction of impacted mandibular third molars, resulting in transient/permanent dysesthesia or paresthesia, is around 0.4% to 13.4%. Aims and Objectives: The study's goal was to use cone beam computed tomography (CBCT) to examine the three-dimensional anatomic association between the impacted mandibular third molars and the mandibular canal and to develop a risk prediction model to screen inferior alveolar nerve injuries. Materials and Methods: DICOM files of 300 cases were retrieved and analyzed according to the parameters. Descriptive statistics and a Chi-square test were used to assess the association between different variables and logistic regression to develop a risk prediction model to screen inferior alveolar nerve injuries. Results: Inter-observer and intra-observer agreements were excellent for all CBCT variables. Direct contact of the third molar with the mandibular canal was seen in 61.7% of the cases. Statistically significant association was found for loss of corticalization (OR-5.95; P = 0.000), narrowing (OR-18.916; P = 0.000), and dilacerations of roots (OR-3.8; P = 0.004) with “direct contact” of the impacted mandibular third molar to the mandibular canal. Conclusion: Preoperative assessment with CBCT entails the opportunity to ascertain the “high-risk” impacted mandibular third molars at a cheaper cost, with less equipment maintenance and reduced exposure, compared to computed tomography (CT) imaging.

Evaluation of the depth of submandibular gland fossa and its correlation with mandibular canal in vertical and horizontal locations using CBCT

Introduction: To maintain the structural and functional integrity of bone, similar to the natural tooth, Dental implants are most widely used for treatment of edentulous areas in the mouth. Aim and Objectives: Aim of this study is to evaluate the depth of submandibular gland fossa and its relationship with the mandibular canal, based on gender and side of the mandible. Materials and Methods: CBCT scans of 100 patients of both males and females were studied. The deepest region of submandibular gland fossa and the superior, parallel, and the inferior relationship of the mandibular canal to submandibular gland fossae were obtained. Results: The mean ± SD of the depth of the submandibular gland fossa on the right side in males and females were 1.72 ± 0.431 mm and 1.68 ± 0.327mm, respectively, and those on the left were 1.75 ± 0.385 mm and 1.49± 0.295mm respectively. The deepest region in both the genders was above the infra alveolar canal. Conclusion: Greater depths were seen in males in comparison to females, Greater depth was seen in the right side of the mandible as compared to the left side in both males and females. Hence, while placing implants, thickness of the alveolar bone should be evaluated cautiously in males.

Analysis of the mandibular molars root canals morphology. Study by computed tomography.

This study aimed to analyze the root and root canal morphology of mandibular first and second molars using CBCT images. A total of 2,400 mandibular molars exams were selected from 600 patients aged between 18 and 75 years. The number of roots, number of root canals, and root canal configuration according to the Vertucci classification were verified. Overall, 94.92% of mandibular first molars and 90.17% of mandibular second molars had two separate roots. Among the biradicular molars, the first molars showed a greater incidence of type IV canals in the mesial root and type I in the distal root. In the second molars, the most common canal form was type IV in the mesial root and type I in the distal root. In the triradicular molars, the type IV and type I configurations were the most common in the mesial root of the first molar and second molar, respectively. In both triradicular molars, there was a prevalence of type I canal in the distal and DL roots. Statistical analysis was performed at a significance level of 0.05. The number of roots was correlated with gender (Spearman test), and the canal's configuration with gender and bilaterality (Wilcoxon test). The subpopulation studied has a high incidence of bilateral symmetry and mandibular molars with two roots with two distinct mesial canals and one distal canal. The bilateral configuration is possible to estimate the number of canals, especially in images that are difficult to visualize, such as atresic canals.

The Radiological Evaluation of Mandibular Canal Related Variables in Mandibular Third Molar Region: a Retrospective Multicenter Study.

The aim of this retrospective study was to investigate anatomical structure of mandibular canal and the factors those increase the possibility of inferior alveolar nerve damage in mandibular third molar region of Turkish population. Overall 320 participants with 436 mandibular third molars were included from four different study centers. Following variables were measured: type and depth of third molar impaction, position of mandibular canal in relation to third molars, morphology of mandibular canal, cortication status of mandibular canal, possible contact between the third molars and mandibular canal, thickness and density of superior, buccal, and lingual mandibular canal wall, bucco-lingual and apico-coronal mandibular canal diameters on cone-beam computed tomography scans. Lingual mandibular canal wall density and thickness were decreased significantly as the impaction depth of mandibular third molar was increased (P = 0.045, P = 0.001 respectively). Highest buccal mandibular canal wall density and thickness were observed in lingual position of mandibular canal in relation to mandibular third molar (P = 0.021, P = 0.034 respectively). Mandibular canal with oval/round morphology had higher apico-coronal diameter in comparison to tear drop and dumbbell morphologies (P = 0.018). Additionally, mandibular canals with observed cortication border and no contact with mandibular third molar had denser and thicker lingual mandibular canal wall (P = 0.003, P = 0.001 respectively). Buccal and lingual mandibular canal wall density, thickness and mandibular canal diameter may be related with high-risk indicators of inferior alveolar nerve injury.

Mandibular canal and the arrangement of the neurovascular bundle exit routes in divergent populations

Aim: In face anatomy and surgery, variation in the presence, number, location, and size of the mental foramen is discussed. Knowledge of the location of the mental foramen canal, which may led due to the possibility of accidental injury of the neurovascular bundle passing through this canal may lead to anesthesia. This study aimed to present selected anatomical features of human mandibles, focusing on the morphology of the mandibular canal and its neurovascular bundle exit in populations with different socio-economic status. Material and methods: Selected well preserved and unharmed human skulls (N= 169) (50.3% males, 49.7% females) from two populations (rural and outskirts) from Poland were used. Populations differed in socio­economic statuses. Results: Obvious dimorphic differences in each analyzed population were stated and inter-population differences were observed as well. In an outskirt population sexual dimorphism was more evident. Those differences should be considered when approaching the mandibular canal during anesthetic, surgical and forensic procedures. Discussion: The occurrence of the mental foramen is relatively constant, but location is variable, and thus, each individual may exhibit a different arrangement of bundle exits. Both the position and the direction of the exit of the neurovascular bundle were similar to other European population. However, differences in localization between those two investigated populations were observed. This may suggest that not only genetic but also environmental factors, such as living conditions and diet (which affects developmental stability), may influence the morphology of the mandibular features.

Anatomical Variations of the Mandibular Canal and Mental Foramen in Full Edentulous Iranian Subpopulation: A Cone-Beam Computed Tomographic Study

Background: This study sought to determine the anatomical variations of the mental foramen (MF) and the mandibular canal (MC) in the full edentulous Iranian subpopulation using cone-beam computed tomography (CBCT). These variations can have significant clinical implications in dental implant surgery. Methods: This descriptive cross-sectional study evaluated the mandible CBCT scans of 384 completely edentulous patients that required dental implant treatment. The CBCT scans were retrieved from four radiology clinics in Tehran, Iran, using quota sampling. The reconstructed images were evaluated to determine the dimensions and position of the MC and its cortication at the site of the mandibular first molar, the branching of the MC, the existence of the anterior loop of the mental nerve, and anatomical variations of the MF. The correlations of variables with age and gender were analyzed using the independent t-test, chi-square test, and analysis of variance based on the type of the variable. Results: The cortication of the MC at the site of the mandibular first molar was present in 72.9% of the cases and was significantly more common in male patients (P = 0.0001). Bifid mandibular canal, accessory MF, and anterior loop of mental nerve were present in 9.9%, 65%, and 54.7% of the samples, respectively, and they had no significant correlation with age/gender. The mean MC diameter, the mean MF height, and the mean distance from the inferior border of the mandible to the center of MF were all significantly higher in male patients (P

Prevalence and Characterization of bifid mandibular Canal Using Cone Beam Computed Tomography: A Retrospective Cross-Sectional Study in Saudi Arabia.

AimThe purpose of this study is to determine the prevalence and morphological characteristics of the bifid mandibular canal in a Saudi Arabian subpopulation, to aid in preventing surgical complications near the mandibular canal.Patients and MethodsUsing CBCT images obtained from the Radiology unit database in a University Hospital Clinics. A total of 488 CBCT images were investigated (244 Female – 178 Male). In the present study, the Naitoh classification was used to categorize the bifid mandibular canal into the following types: 1) Retromolar canal; 2) Dental canal; 3) Forward canal (with or without confluence); and 4) Buccolingual canal. Additional variation (Trifid canal) was included. All CBCTs were assessed in coronal, sagittal, axial, as well as panoramic views using specialized software.ResultsThe prevalence of BMC was 28.7% (95% CI, 24.5 to 33.2), Gender (p = 0.404) and age (p = 0.654) had no statistical significances, laterality of BMC, patients with unilateral BMC were significantly older than those with bilateral BMC (mean ± SD ages of 40.5 ± 13.5 and 32.9 ± 13.8, respectively, p = 0.009). About two-thirds (67.5%) of the investigated BMC cases were found unilateral. The most common reported type of BMC was retromolar canal.ConclusionThe incidence of bifid mandibular canal using CBCT is considered relatively high in Saudi Arabian subpopulation, with the most common type was the retro-molar canal.

ASSESSMENT OF JUXTA-APICAL RADIOLUCENCY WITH CONE BEAM CT

Aim: This study aimed to investigate the association of JAR with third molar status and mandibular canal and also describe its radiologic features through cone beam computed tomography (CBCT).&#x0D; Methods: CBCT images of 100 individuals (153 mandibular third molars) were evaluated for the presence of JAR. Than, the CBCT images were analysed to evaluate the position of the JAR and its relationship to the impacted teeth, mandibular canal and buccal-lingual cortical plates. Descriptive statistical analyses were used.&#x0D; Results: JAR was identified in 70 individuals and 95 mandibular third molars (48 right side, 47 left side). 22 of the individuals with JAR were male and 48 were female. It was found that 26 (27,4%) of the 95 third molars were erupted, 10 (10,5%) were partially erupted, 59 (62,1%) were impacted. 74,7 % were on the apical third of the root and the rest was located along the mesial or distal surfaces of root. Close proximity to the buccal cortical plate was seen in 25,35 % of JAR located apically, whereas it was seen only 25% of JAR located along the root surface. Only 23.4 % were associated with the mandibular canal.&#x0D; Conclusion: The present study gives an insight into the relationship of JAR with mandibular canal and cortical plates using CBCT. However, future studies are warranted that use a larger sample size to validate the above findings.

An evaluation of mandibular canal variations: a systematic review and meta-analysis.

The inferior alveolar nerve and vessels are carried via the mandibular canal, which extends bilaterally from the inferior alveolar foramen to the mental foramen. Bifid and trifidmandibular canals result from abnormal fusions of nerve canals. The purpose of this study was to provide an up-to-date and comprehensive analysis of the prevalence ofmandibular canalvariations among healthy adults, and to identify any potential ethnic, sex, or laterality predilections. The prevalence of the bifid mandibular canal was 18.87% and that of the trifid canal 1.3%. Unilateral variants were three times commoner than bilateral. Eachmandibular half had four canals emanating from separate openings on the lingual surface of the mandibular ramus. Retromolar and forward canals were the predominant subtypes, followed by dental; buccolingual were the least frequent. The mean length and diameter ofthe bifid mandibular canalwere 13.62mm and 1.63mm, respectively. The possibility of a bifid mandibular canal is a crucial consideration in dental medicine. Because anatomical variations of themandibular canal are fairly common, awareness of them is essential for anatomy teachers and for surgeons who operate in the oromaxillofacial region.

A Fused Deep Learning Architecture for the Detection of the Relationship between the Mandibular Third Molar and the Mandibular Canal.

The study aimed to generate a fused deep learning algorithm that detects and classifies the relationship between the mandibular third molar and mandibular canal on orthopantomographs. Radiographs (n = 1880) were randomly selected from the hospital archive. Two dentomaxillofacial radiologists annotated the data via MATLAB and classified them into four groups according to the overlap of the root of the mandibular third molar and mandibular canal. Each radiograph was segmented using a U-Net-like architecture. The segmented images were classified by AlexNet. Accuracy, the weighted intersection over union score, the dice coefficient, specificity, sensitivity, and area under curve metrics were used to quantify the performance of the models. Also, three dental practitioners were asked to classify the same test data, their success rate was assessed using the Intraclass Correlation Coefficient. The segmentation network achieved a global accuracy of 0.99 and a weighted intersection over union score of 0.98, average dice score overall images was 0.91. The classification network achieved an accuracy of 0.80, per class sensitivity of 0.74, 0.83, 0.86, 0.67, per class specificity of 0.92, 0.95, 0.88, 0.96 and AUC score of 0.85. The most successful dental practitioner achieved a success rate of 0.79. The fused segmentation and classification networks produced encouraging results. The final model achieved almost the same classification performance as dental practitioners. Better diagnostic accuracy of the combined artificial intelligence tools may help to improve the prediction of the risk factors, especially for recognizing such anatomical variations.