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This study aimed to identify risk factors associated with perforation of the undercut (U)-shaped lingual plate (LP) by the lower third molar (LM3) root using panoramic radiography (PAN). We retrospectively examined 468 impacted LM3s from 468 individuals, categorizing LM3–LP associations and LP morphology in the coronal section of cone-beam computed tomography as perforation or nonperforation and U-type or non-U-type, respectively. The outcome was the combination of perforation and U-type, and study variables included patient demographics (age and sex) and PAN-associated features (Winter's classification, Pell–Gregory classification, and two major Rood signs). Multivariate logistic regression methods were used for analysis. Perforated and U-type LPs were observed in 205 (43.8%) and 212 (45.3%) cases, respectively. The double-positive outcome was observed in 126 LM3s (26.9%). In the multivariate model, age ≥ 26 years [odds ratio (OR), 2.66; p = 0.002], men (OR, 2.01; p = 0.002), mesioangular (OR, 2.74; p = 0.038) and horizontal impaction (OR, 3.05; p = 0.019), and root darkening (OR, 1.73; p = 0.039) were independently associated with the risk. Class III impaction (OR, 0.35; p = 0.021) and interruption of the white line (OR, 0.55; p = 0.017) were negatively correlated with the risk. In conclusion, this study highlights the importance of identifying the higher probability of U-type LP perforation by the LM3 root in men aged over their midtwenties with Class I/II impaction and mesioangularly or horizontally impacted LM3s, along with root darkening and no interruption of the white line on PAN. [ABSTRACT FROM AUTHOR]

Aim: The purpose of this study to evaluate and categorize the complexity of extracting impacted mandibular third molars (IMTMs) using cone beam computed tomography (CBCT).Materials and methods: CBCT used to analyze 315 lower third molars from 182 patients who met the inclusion criteria. CBCT scans were acquired with a CS 9300 Premium 3D machine. Patient demographics and IMTM details were recorded by two observers using CS 3D Imaging Software for image analysis. Descriptive statistics were applied to assess criteria for impaction and extraction difficulty. Differences in surgical risk indicators for IMTM extraction were statistically examined between age groups, gender, and ethnicities using Fisher’s exact test. Results: Patients aged 18-75 years showed that mesioangular impaction was most common at 41.90%, followed by horizontal at 30.79%, vertical at 25.72%, distoangular at 0.95%, and inverted at 0.63%. Class IA and IIA classifications were most prevalent at 27.30% and 23.49%, respectively, with Class IIIA being the least common at 1.58%. significantly higher surgical difficulty indicators seen in patients under 40 compared to older patients for right and left IMTMs (p = 0.026 and 0.011, respectively), but no statistically significant differences in these indicators were observed between genders or ethnicities.Conclusion: CBCT examination revealed that mesioangular impaction was the most frequent occurrence, followed by horizontal, vertical, distoangular, and inverted impactions. Class IA and IIA prevalent; Class IIIA least common. Surgical difficulty indication more in younger than 40 years old patients, no gender or ethnicity differences.

Abstract Background The routine application of dental implants for replacing missing teeth has revolutionized restorative and prosthetic dentistry. However, cone beam computed tomography (CBCT) evaluations of structures adjacent to the implants are limited by metal artifacts. There are several methods for reducing metal artifacts, but this remains a challenging task. This study aimed to examine the effectiveness of metal artifact reduction (MAR) algorithms in identifying injuries of implants to the inferior alveolar canal in CBCT images. Method In this in vitro study, mono-cortical bone windows were created and the inferior alveolar canal was revealed. Using 36 implants, pilot drill and penetration damage of the implant tip into the canal was simulated and compared to the control implants with distance from the canal. CBCT images were evaluated by four experienced observers with and without the MAR algorithm and compared to direct vision as the gold standard. The values of accuracy, sensitivity, and specificity were obtained and compared by receiver operating characteristic (ROC) curve (α = 0.05). Result The area under the ROC curve values for detection of pilot drill injuries varied between 0.840–0.917 and 0.639–0.854 in the active and inactive MAR conditions, respectively. The increase in ROC area was only significant for one of the observers (P = 0.010). For diagnosing penetrative injuries, the area under the ROC curve values was between 0.990–1.000 and 0.722–1.000 in the active and inactive MAR conditions, respectively. The improvement of ROC curve values in active MAR mode was only significant for one of the observers (P = 0.006). Conclusion Activation of MAR improved the diagnostic values of CBCT images in detecting both types of implant-related injuries to the inferior alveolar canal. However, for most observers, this increase was not statistically significant.

Segmentation of the Inferior Alveolar Canal (IAC) is a critical aspect of dentistry and maxillofacial imaging, garnering considerable attention in recent research endeavors. Deep learning techniques have shown promising results in this domain, yet their efficacy is still significantly hindered by the limited availability of 3D maxillofacial datasets. An inherent challenge is posed by the size of input volumes, which necessitates a patch-based processing approach that compromises the neural network performance due to the absence of global contextual information. This study introduces a novel approach that harnesses the spatial information within the extracted patches and incorporates it into a Transformer architecture, thereby enhancing the segmentation process through the use of prior knowledge about the patch location. Our method significantly improves the Dice score by a factor of 4 points, with respect to the previous work proposed by Cipriano et al., while also reducing the training steps required by the entire pipeline. By integrating spatial information and leveraging the power of Transformer architectures, this research not only advances the accuracy of IAC segmentation, but also streamlines the training process, offering a promising direction for improving dental and maxillofacial image analysis.

Introduction: Cone beam computed tomography (CBCT) plays a significant role in studying the anatomical structures of the mandible. Aim: This retrospective study aimed to assess the role of CBCT at the pre-assessment stage of mandibular surgery. Materials and methods: A total of 250 CBCT images were collected. The inferior alveolar canal (IAC) and mental foramen (MF) were measured bilaterally to the mandibular teeth apexes, including molars, premolars, and canines, to the buccal, lingual cortical bone, and to the inferior border of the mandible. Results: There were no differences in the average number of extracted teeth between the right and left sides (P-value > 0.05, median = three teeth). It was noticed that the average measures of each point of the IAC and MF on the right side were closely matched to the similar point on the left side (P-value > 0.05). T-tests showed that there were differences between males and females on the M2 and M3 on the right side (P-value

Background: The routine application of dental implants for replacing missing teeth has revolutionized restorative and prosthetic dentistry. However, cone beam computed tomography (CBCT) evaluations of structures adjacent to the implants are limited by metal artifacts. There are several methods for reducing metal artifacts, but this remains a challenging task. This study aimed to examine the effectiveness of metal artifact reduction (MAR) algorithms in identifying injuries of implants to the inferior alveolar canal in CBCT images. Method: In this in vitro study, mono-cortical bone windows were created and the inferior alveolar canal was revealed. Using 36 implants, pilot drill and penetration damage of the implant tip into the canal was simulated and compared to the control implants with distance from the canal. CBCT images were evaluated by four experienced observers with and without the MAR algorithm and compared to direct vision as the gold standard. The values of accuracy, sensitivity, and specificity were obtained and compared by receiver operating characteristic (ROC) curve (α = 0.05). Result: The area under the ROC curve values for detection of pilot drill injuries varied between 0.840–0.917 and 0.639–0.854 in the active and inactive MAR conditions, respectively. The increase in ROC area was only significant for one of the observers (P = 0.010). For diagnosing penetrative injuries, the area under the ROC curve values was between 0.990–1.000 and 0.722–1.000 in the active and inactive MAR conditions, respectively. The improvement of ROC curve values in active MAR mode was only significant for one of the observers (P = 0.006). Conclusion: Activation of MAR improved the diagnostic values of CBCT images in detecting both types of implant-related injuries to the inferior alveolar canal. However, for most observers, this increase was not statistically significant. [ABSTRACT FROM AUTHOR]

Cone beam computed tomography (CBCT) plays a significant role in studying the anatomical structures of the mandible. This retrospective study aimed to assess the role of CBCT at the pre-assessment stage of mandibular surgery. A total of 250 CBCT images were collected. The inferior alveolar canal (IAC) and mental foramen (MF) were measured bilaterally to the mandibular teeth apexes, including molars, premolars, and canines, to the buccal, lingual cortical bone, and to the inferior border of the mandible. There were no differences in the average number of extracted teeth between the right and left sides (P-value > 0.05, median = three teeth). It was noticed that the average measures of each point of the IAC and MF on the right side were closely matched to the similar point on the left side (P-value > 0.05). T-tests showed that there were differences between males and females on the M2 and M3 on the right side (P-value < 0.05) and on the M1, M2, and M3 on the left side (P-value < 0.05). Using one-way ANOVA tests, results showed that there were some differences in measures at P0 (F = 3.376, P-value = 0.003), P4 (F = 3.782, P-value = 0.001) on the right side, and at P3 (F = 5.620, P-value = 0.019) on the left side of the mandible. There were no significant differences in IAC and MF positions between the right and left sides. However, between males and females, MF measurements showed significant differences on some points on the right and left sides. Although the history of extracted teeth showed no statistically significant difference in the location of IAC and MF, the number of extracted teeth showed an effect in the IAC position on the right and left sides, but not with the MF. [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 Background The injury of the inferior alveolar nerve (IAN) is one of the most serious complications of impacted mandibular third molars (IMTMs) extraction. The influence of the root orientation of IMTMs on IAN injury is still controversial. A deeper understanding of the risk factors of IAN injury conduces to better prevention of IAN injury. This study aims to explore whether root orientation is an independent risk factor of IAN injury during IMTMs extraction using the statistical strategy of propensity score matching (PSM). Methods This retrospective cohort study included 379 patients with 539 cases of high-risk IMTMs screened by panoramic radiography and cone beam computed tomography. The IAN injury incidence after extraction of different groups of IMTMs was analyzed using the chi-square test or Fisher’s exact test. The correlation between third molar root orientation and impaction depth/contact degree with IAN was evaluated by the Lambda coefficient. Based on PSM for balancing confounding factors including age, sex, impaction depth, and contact degree, the effect of root orientation on the incidence of IAN injury was further analyzed using Fisher’s exact test. Results There were significant group differences in IAN injury incidence in impaction depth, root orientation, and contact degree of root-IAC before PSM. Root orientation was correlated with impaction depth and contact degree of root-IAC. After PSM, there were 9 cases with IAN injury and 257 cases without IAN injury. There were significant group differences between the buccal and non-buccal groups after PSM, and the risk of IAN injury was higher when the root was located on the buccal side of IAC (OR = 8.448, RR = 8). Conclusions Root orientation is an independent risk factor of IAN injury, and the risk is higher when the root is located on the buccal side of IAC. These findings could help better evaluate the risk of inferior alveolar nerve injury before the extraction of IMTMs.

Abstract The purpose of this study was to automatically classify the three-dimensional (3D) positional relationship between an impacted mandibular third molar (M3) and the inferior alveolar canal (MC) using a distance-aware network in cone-beam CT (CBCT) images. We developed a network consisting of cascaded stages of segmentation and classification for the buccal-lingual relationship between the M3 and the MC. The M3 and the MC were simultaneously segmented using Dense121 U-Net in the segmentation stage, and their buccal-lingual relationship was automatically classified using a 3D distance-aware network with the multichannel inputs of the original CBCT image and the signed distance map (SDM) generated from the segmentation in the classification stage. The Dense121 U-Net achieved the highest average precision of 0.87, 0.96, and 0.94 in the segmentation of the M3, the MC, and both together, respectively. The 3D distance-aware classification network of the Dense121 U-Net with the input of both the CBCT image and the SDM showed the highest performance of accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve, each of which had a value of 1.00. The SDM generated from the segmentation mask significantly contributed to increasing the accuracy of the classification network. The proposed distance-aware network demonstrated high accuracy in the automatic classification of the 3D positional relationship between the M3 and the MC by learning anatomical and geometrical information from the CBCT images.

Background: The injury of the inferior alveolar nerve (IAN) is one of the most serious complications of impacted mandibular third molars (IMTMs) extraction. The influence of the root orientation of IMTMs on IAN injury is still controversial. A deeper understanding of the risk factors of IAN injury conduces to better prevention of IAN injury. This study aims to explore whether root orientation is an independent risk factor of IAN injury during IMTMs extraction using the statistical strategy of propensity score matching (PSM). Methods: This retrospective cohort study included 379 patients with 539 cases of high-risk IMTMs screened by panoramic radiography and cone beam computed tomography. The IAN injury incidence after extraction of different groups of IMTMs was analyzed using the chi-square test or Fisher's exact test. The correlation between third molar root orientation and impaction depth/contact degree with IAN was evaluated by the Lambda coefficient. Based on PSM for balancing confounding factors including age, sex, impaction depth, and contact degree, the effect of root orientation on the incidence of IAN injury was further analyzed using Fisher's exact test. Results: There were significant group differences in IAN injury incidence in impaction depth, root orientation, and contact degree of root-IAC before PSM. Root orientation was correlated with impaction depth and contact degree of root-IAC. After PSM, there were 9 cases with IAN injury and 257 cases without IAN injury. There were significant group differences between the buccal and non-buccal groups after PSM, and the risk of IAN injury was higher when the root was located on the buccal side of IAC (OR = 8.448, RR = 8). Conclusions: Root orientation is an independent risk factor of IAN injury, and the risk is higher when the root is located on the buccal side of IAC. These findings could help better evaluate the risk of inferior alveolar nerve injury before the extraction of IMTMs. [ABSTRACT FROM AUTHOR]

The purpose of this study was to automatically classify the three-dimensional (3D) positional relationship between an impacted mandibular third molar (M3) and the inferior alveolar canal (MC) using a distance-aware network in cone-beam CT (CBCT) images. We developed a network consisting of cascaded stages of segmentation and classification for the buccal-lingual relationship between the M3 and the MC. The M3 and the MC were simultaneously segmented using Dense121 U-Net in the segmentation stage, and their buccal-lingual relationship was automatically classified using a 3D distance-aware network with the multichannel inputs of the original CBCT image and the signed distance map (SDM) generated from the segmentation in the classification stage. The Dense121 U-Net achieved the highest average precision of 0.87, 0.96, and 0.94 in the segmentation of the M3, the MC, and both together, respectively. The 3D distance-aware classification network of the Dense121 U-Net with the input of both the CBCT image and the SDM showed the highest performance of accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve, each of which had a value of 1.00. The SDM generated from the segmentation mask significantly contributed to increasing the accuracy of the classification network. The proposed distance-aware network demonstrated high accuracy in the automatic classification of the 3D positional relationship between the M3 and the MC by learning anatomical and geometrical information from the CBCT images. [ABSTRACT FROM AUTHOR]

INTRODUCTION: In the forensic field, different races or ethnicity present various skeletal status or skull pattern, which aid in racial identification. OBJECTIVES: Our study evaluated the deepest lingual concavity depth in the posterior region of the mandible, and its relation to the inferior alveolar canal using cone beam computed tomography (CBCT), and to associate the findings to different gender, age, and race in Malaysia. MATERIAL AND METHODS: A retrospective analysis of 384 CBCT scans was done on both left and right sides of the mandible. Position of the deepest lingual concavity depth was evaluated in relation to the inferior alveolar canal, and categorized into 3 groups: above the canal, at the same level as the canal, and below the canal. Analysis was carried out for different gender, age groups, and races in Malaysia. RESULTS: The mean age of the study participants was 36.6 ± 14.6 years, and there was no significant relationship between the deepest lingual concavity depth and age. The mean lingual concavity depth was 2.23 ± 0.76 mm in male subjects, and 1.74 ± 0.61 mm in female subjects. The mean lingual concavity depth was highest in Indian (2.20 ± 0.73 mm), followed by Malay (2.00 ± 0.73 mm), and Chinese (1.80 ± 0.69 mm) populations. CONCLUSIONS: Due to variations in the depth and the risk of penetration, with decision made solely on lingual concavity depth and its relation to the inferior alveolar canal, the assessment of implant fixture site is recommended to be done on a case-by-case basis during pre-operative planning for dental implant surgery. [ABSTRACT FROM AUTHOR]

Abstract Background This study aims at evaluating the visibility levels of the inferior alveolar canal (IAC) at different mandibular sites using panoramic (conventional & CBCT reformatted) and CBCT coronal views in a sample of a Palestinian population. Methods The panoramic (conventional [CP] & CBCT reformatted [CRP]) and CBCT coronal views (CCV) of 103 patients (206 records, right and left sides) were analyzed. The visibility of IAC at five sites extending from the first premolar to the third mandibular molar region was evaluated visually (and compared among the radiographic views) as clearly visible, probably visible, invisible/poorly visible, or not present at the examined site. On CCV, the maximum dimension of the IAC (MD), the vertical distance (VD) between the mandibular cortex and IAC, and the horizontal position (HP) of the IAC were noted. Statistical significance in the differences and relationships of the variables was tested using several statistical tests. Results There was a statistically significant relationship between the radiography modality (CP, CRP, CCV) and the visibility level of IAC (assessed in scores) at the five mandibular sites. When assessed on CP, CRP, and CCV, the IAC was clearly visible at all sites in 40.4%, 30.9%, and 39.6%, respectively, while being invisible/poorly visible in 27.5%, 38.9%, and 7.2% for the same views, respectively. The mean values of MD and VD were 3.61 mm and 8.48 mm, respectively. Conclusion Different radiographic modalities would characterize the IAC’s structure in different qualities. Superior visibility levels were obtained interchangeably using CBCT cross-sectional views and conventional panorama at different sites compared to CBCT reformatted panorama. The IACs visibility was noted to improve at their distal aspects irrespective of the radiographic modality used. Gender —but not age— was a significant factor in the visibility level of IAC at only two mandibular sites.

Background/purpose: In lower third molar (LM3) surgery, panoramic radiography (PAN) is important for the initial assessment of the anatomical association between LM3 and the inferior alveolar nerve (IAN). This study aimed to develop a deep learning model for the automated evaluation of the LM3–IAN association on PAN. Further, its performance was compared with that of oral surgeons using original and external datasets. Materials and methods: In total, 579 panoramic images of LM3 from 384 patients in the original dataset were utilized. The images were divided into 483 images for the training dataset and 96 for the testing dataset at a ratio of 83:17. The external dataset comprising 58 images from an independent institution was used for testing only. The LM3–IAN associations on PAN were categorized into direct or indirect contact based on cone-beam computed tomography (CBCT). The You Only Look Once (YOLO) version 3 algorithm, a fast object detection system, was applied. To increase the amount of training data for deep learning, PAN images were augmented using the rotation and flip techniques. Results: The final YOLO model had high accuracy (0.894 in the original dataset and 0.927 in the external dataset), recall (0.925, 0.919), precision (0.891, 0.971), and f1-score (0.908, 0.944). Meanwhile, oral surgeons had lower accuracy (0.628, 0.615), recall (0.821, 0.497), precision (0.607, 0.876), and f1-score (0.698, 0.634). Conclusion: The YOLO-driven deep learning model can help oral surgeons in the decision-making process of applying additional CBCT to confirm the LM3–IAN association based on PAN images.

Background: This study aims at evaluating the visibility levels of the inferior alveolar canal (IAC) at different mandibular sites using panoramic (conventional & CBCT reformatted) and CBCT coronal views in a sample of a Palestinian population. Methods: The panoramic (conventional [CP] & CBCT reformatted [CRP]) and CBCT coronal views (CCV) of 103 patients (206 records, right and left sides) were analyzed. The visibility of IAC at five sites extending from the first premolar to the third mandibular molar region was evaluated visually (and compared among the radiographic views) as clearly visible, probably visible, invisible/poorly visible, or not present at the examined site. On CCV, the maximum dimension of the IAC (MD), the vertical distance (VD) between the mandibular cortex and IAC, and the horizontal position (HP) of the IAC were noted. Statistical significance in the differences and relationships of the variables was tested using several statistical tests. Results: There was a statistically significant relationship between the radiography modality (CP, CRP, CCV) and the visibility level of IAC (assessed in scores) at the five mandibular sites. When assessed on CP, CRP, and CCV, the IAC was clearly visible at all sites in 40.4%, 30.9%, and 39.6%, respectively, while being invisible/poorly visible in 27.5%, 38.9%, and 7.2% for the same views, respectively. The mean values of MD and VD were 3.61 mm and 8.48 mm, respectively. Conclusion: Different radiographic modalities would characterize the IAC's structure in different qualities. Superior visibility levels were obtained interchangeably using CBCT cross-sectional views and conventional panorama at different sites compared to CBCT reformatted panorama. The IACs visibility was noted to improve at their distal aspects irrespective of the radiographic modality used. Gender —but not age— was a significant factor in the visibility level of IAC at only two mandibular sites. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to train deep learning models for recognition of contiguity between the mandibular third molar (M3M) and inferior alveolar canal using panoramic radiographs and to investigate the best effective fold of data augmentation. Materials and methods: The total of 1800 M3M cropped images were classified evenly into contact and no-contact. The contact group was confirmed with CBCT images. The models were trained from three pretrained models: AlexNet, VGG-16, and GoogLeNet. Each pretrained model was trained with the original cropped panoramic radiographs. Then the training images were increased fivefold, tenfold, 15-fold, and 20-fold using data augmentation to train additional models. The area under the receiver operating characteristic curve (AUC) of the 15 models were evaluated. Results: All models recognized contiguity with AUC from 0.951 to 0.996. Ten-fold augmentation showed the highest AUC in all pretrained models; however, no significant difference with other folds were found. VGG-16 showed the best performance among pretrained models trained at the same fold of augmentation. Data augmentation provided statistically significant improvement in performance of AlexNet and GoogLeNet models, while VGG-16 remained unchanged. Conclusions: Based on our images, all models performed efficiently with high AUC, particularly VGG-16. Ten-fold augmentation showed the highest AUC by all pretrained models. VGG-16 showed promising potential when training with only original images. Clinical relevance: Ten-fold augmentation may help improve deep learning models' performances. The variety of original data and the accuracy of labels are essential to train a high-performance model. [ABSTRACT FROM AUTHOR]

In lower third molar (LM3) surgery, panoramic radiography (PAN) is important for the initial assessment of the anatomical association between LM3 and the inferior alveolar nerve (IAN). This study aimed to develop a deep learning model for the automated evaluation of the LM3–IAN association on PAN. Further, its performance was compared with that of oral surgeons using original and external datasets. In total, 579 panoramic images of LM3 from 384 patients in the original dataset were utilized. The images were divided into 483 images for the training dataset and 96 for the testing dataset at a ratio of 83:17. The external dataset comprising 58 images from an independent institution was used for testing only. The LM3–IAN associations on PAN were categorized into direct or indirect contact based on cone-beam computed tomography (CBCT). The You Only Look Once (YOLO) version 3 algorithm, a fast object detection system, was applied. To increase the amount of training data for deep learning, PAN images were augmented using the rotation and flip techniques. The final YOLO model had high accuracy (0.894 in the original dataset and 0.927 in the external dataset), recall (0.925, 0.919), precision (0.891, 0.971), and f1-score (0.908, 0.944). Meanwhile, oral surgeons had lower accuracy (0.628, 0.615), recall (0.821, 0.497), precision (0.607, 0.876), and f1-score (0.698, 0.634). The YOLO-driven deep learning model can help oral surgeons in the decision-making process of applying additional CBCT to confirm the LM3–IAN association based on PAN images. [ABSTRACT FROM AUTHOR]

The clinical issues related to the anatomical variation of the mandibular canal have been extensively analyzed since the 19th century. Evolving dentistry techniques and advancements in the prosthetics forced to collect detailed information about anatomical variations of the mandibular canal due to its neurovascular content. Therefore, its radiographic imaging became an essential part of the oral surgery, in order to avoid complications resulted from an accidental damage of the mandibular canal. [ABSTRACT FROM AUTHOR]

Inferior alveolar canal (IAC) is an important anatomical landmark in dentistry. It is a bony canal in the mandible, one on each side and transmit inferior alveolar neurovascular bundle. However, it has been reported to have anatomical variations in its course. IAC is visible on radiographs and cone beam computed tomography (CBCT) has been identified as the one of the best methods to assess IAC preoperatively. An interesting case of IAC anatomy in a CBCT is presented here. There were accessory mandibular foramina, retromolar foramina on both sides, accessory mental foramen on the right side and lingual foramina in the midline as well as on the body of the mandible. The IAC was showing several branching within ramus as well as in the body of the mandible. This case report highlights the possible anatomical variations and importance of careful assessment of IAC in dental and maxillofacial procedures which can cause damage to the neurovascular bundle. [ABSTRACT FROM AUTHOR]

We previously developed basic and extended models to predict inferior alveolar nerve injuries (IANI) after lower third molar (LM3) removal based on cone-beam computed tomography (CBCT) images. Although these models comprised predictors, including increased age and inferior alveolar canal-related CBCT factors, external validations were lacking. Therefore, this study externally validated these models and compared them with other related models based on their performance. Original and newly validated samples included patients who underwent LM3 removal following CBCT. Subsequently, 39 and 25 patients with IANI, then 457 and 295 randomly selected patients without IANI were chosen of the observed 1573 and 1052 patients, respectively. CBCT- and panoramic radiograph (PAN)-featured models were validated. Then, models' discrimination and calibration abilities were assessed using C-statistics and calibration plots, respectively. Brier scores were also quantified, after which logistic recalibration was achieved to optimize calibration, and a risk calculator was developed. During the external validation, the extended model exhibited the best C-statistic (0.822) and Brier score (0.064), whereas two CBCT- and two PAN-featured models showed lower performances with C-statistics (0.764, 0.706, 0.584, and 0.627) and Brier scores (0.069, 0.074, 0.075, and 0.072). Besides, all models showed a tendency to overpredict its high-risk range. However, recalibration of the extended model resulted in excellent calibration performance. CBCT-featured models, especially the extended model, conclusively showed a superior predictive performance to PAN models. Therefore, the risk calculator on the extended CBCT model is proposed to be a clinical decision-aid tool that preoperatively predicts IANI risk. [ABSTRACT FROM AUTHOR]

Objective: This aim of this study was to determine the prevalence and branching patterns of the inferior alveolar canal (IAC) in premolar and molar areas using cone beam computed tomography (CBCT). Method and materials: CBCT volumes from partially or fully edentulous premolar and molar areas were investigated retrospectively. The presence of such branches with their patterns, sides, and areas, as well as the sex of the patient, were recorded by two observers and analyzed statistically. The branching patterns were initially classified into three types: A, superior type; B, forward type; and C, plexus type. During the investigation, an additional type was found in the premolar area and was classified as type D, an anterior extension type. Results: In total, 243 mandibular sites in 176 subjects were included. Among them, 106 sites displayed branches (43.62%). In the premolar area, most branches were of the anterior extension type (D, 33%), followed by the superior and plexus types (A and C, respectively, 29%), and the forward type (B, 9%). In the molar area, the plexus type was the most common finding (C, 39%), followed by the superior type (A, 32%) and the forward type (B, 29%). Branches in the molar area were significantly more frequent in men than in women (P = .011). Conclusion: IAC branches with four branching patterns in the premolar and molar areas are not rare and could be detected by CBCT. Clinicians should be aware of these branches during surgical procedures concerning the posterior mandible. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the position of the root apices of posterior teeth of mandible with inferior alveolar nerve canal and the cortical bone on cone beam computed tomography. Method: The retrospective study was conducted from September to October 2021 at the Aga Khan University Hospital, and comprised cone beam computed tomography scans between November 2017 and October 2021 scans of healthy individuals of either gender aged 18-71 years with healthy, untreated, mandibular posterior teeth bilaterally. Shortest distance from apices of the mandibular posterior teeth to the border of inferior alveolar nerve canal, and to the mandibular buccal cortex were measured on the scans. Data was analysed using SPSS 23. Result: Of the 106 scans, 55(52%) were males and 51(48%) were females. Of the 746 33teeth in the scans, 385(51.6%) were present in the scans of males and 361(48.4%) in those of the females. For all mandibular posterior teeth, the distances in females were shorter than males, but for the distance from root apices to the IAN canal, the difference between genders was significant for the roots of second premolar and second molar only on the left side (p0.05). Regarding the distance from the root apices to the buccal cortex, no significant difference was found between the genders, for each type of tooth, (p>0.05). Correlations between the distance from apex to inferior alveolar nerve (r

Various endodontic interventions often lead to iatrogenic damage to the inferior alveolar nerve present in the inferior alveolar canal (IAC). The purpose of the present study was to analyze the relationships of IAC with the root apices of mandibular teeth and with the mandibular cortical plates. Materials: 116 cone beam computed tomography (CBCT) scans were examined and the shortest distance of IAC with the root apices of mandibular canines, premolars and molars, and with cortical plates was analyzed. The data were statistically analyzed using SPSS. Results: The shortest mean distance between IAC and lingual cortical plate (LCP) was found in the third molar area, and between IAC and buccal cortical plate (BCP) in the second premolar area. A high incidence of 60% direct communication (DC) was present in mandibular second molars; 38% in mandibular third molars; 13% in mandibular second premolars; 12% in mandibular first molars; and 1% in mandibular first premolars. Conclusion: Anteriorly, IAC was found to be significantly present in close approximation to the roots of mandibular canines. Posteriorly, IAC was found to be in significant proximity to the distal roots of mandibular second molars. [ABSTRACT FROM AUTHOR]

Objective: To determine the prevalence of the retromolar canal and its various patterns using cone beam computed tomography (CBCT). Method and Materials: CBCT images with the presence of mandibular third molars from August 2013 to May 2015 were retrospectively investigated. The presence of retromolar canal, its patterns, sides, as well as gender were evaluated by two observers. The pattern of retromolar canal was initially classified into three types: Type A, superior type; Type B, radicular-retromolar type; and Type C, dental type. During the investigation, two additional types were found and further classified: Type D, plexus type; and Type E, forward type. The distribution of retromolar canals between genders and sides was statistically analyzed with Pearson's chisquare test. Results: A total of 201 mandibular sites in 156 subjects (99 women, 57 men) were included. Among them, 128 sites had retromolar canals (63.68%). The presence of retromolar canal was not statistically related to gender or side. Most of the retromolar canals were the radicular-retromolar type (Type B, 38.10%), followed by the superior type (Type A, 29.93%), dental type (Type C, 19.73%), plexus type (Type D, 6.80%), and forward type (Type E, 5.44%). Conclusion: There was a high frequency of retromolar canals and these could be classified into five patterns. The clinician should be aware of this anatomical structure when performing surgical procedures involving the retromolar area. [ABSTRACT FROM AUTHOR]

Introduction: Close relationship between root apices of mandibular teeth and the mandibular canal is related to the risk of complications involving the inferior alveolar nerve. The objective of this study was to determine the spatial relationship of the root apices of mandibular teeth in relation to the mandibular canal. Materials and methods: On the frontal plane of 300 cone beam computed tomography (CBCT) scans, the spatial mutual position and measurements of the vertical and horizontal distance between the tooth root apices and the mandibular canal were determined. Results: For 23 root types out of 26, the roots of the mandibular teeth were found to exhibit a buccal orientation. The exceptions were the mesial roots of the 1st molars and the mesio-buccal roots of the 2nd molars on the right side, which showed a lingual orientation. The distances were measured for 2053 roots. For the teeth on the left side, the mean measurements ranged 0.23-3.77 mm for buccal roots, and the measurement was 0.21 mm for roots located lingually. For the teeth on the right side, the mean measurements ranged 0.38-2.93 mm for buccal rootsand 0.11-0.32 mm for lingual roots. Conclusions: The predominantly buccal orientation of the root apices of the mandibular teeth in relation to the mandibular canal was demonstrated. [ABSTRACT FROM AUTHOR]

Preoperative assessment is essential to prevent inferior alveolar nerve (IAN) injury during surgical extraction of the lower third molar (LM3). Here, we aimed to establish an assessment system to predict IAN injury during surgical extraction of the LM3. We conducted a retrospective cohort study on 115 patients diagnosed as 'high-risk' based on our previous risk assessment method involving three anatomical features of the inferior alveolar canal using computed tomographic (CT) images. We evaluated the occurrence of neurosensory impairment in these high-risk patients, and its association with novel anatomic features based on CT images. Neurosensory impairments were observed in 19 patients (16.5%). The inferior alveolar canal major diameter (p < 0.0001) and lingual bone thickness (p = 0.0039) were significantly associated with the occurrence of neurosensory impairment during LM3 extraction. Receiver operating characteristic curves were used to determine cut-off values of these quantitative factors to specifically predict IAN injury. Preoperative risk assessment with quantitative factors based on anatomical features observed on CT images may facilitate more appropriate surgical planning for patients at a high risk of IAN injury. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to identify the prevalence and extension of the anterior loop (AL) of the mental nerve in different populations and according to different cone-beam computed tomography (CBCT) imaging settings. Materials and Methods: Medline/PubMed, Embase, Scopus, Web of Science, and ProQuest were searched. The main inclusion criterion was ALs evaluated in CBCT images. The quality of studies was assessed with the Joanna Briggs Institute risk of bias checklist. Subgroup analyses were conducted for sex, side, continent, voxel size, field of view, and type of CBCT-reconstruction images with a random-effects model. Results: Sixty-three studies with 13,743 participants (27,075 hemimandibles) were included. An AL was found in 40.6% (95% CI: 32.8%-48.9%, P<0.05) of participants and 36.0% (95% CI: 27.5%-45.5%, P<0.05) of hemimandibles, in 34.9% (95% CI: 25.1%-46.2%, P<0.05) of males and 34.5% (95% CI: 23.5%-47.4%, P<0.05) of females. The average length of ALs was 2.39 mm (95% CI: 2.07-2.70 mm, P<0.05). Their extension was 2.13 mm (95% CI: 1.54-2.73 mm, P<0.05) in males and 1.85 mm (95% CI: 1.35-2.36 mm, P<0.05) in females. Significant differences were observed regarding the prevalence and length of ALs among continents and for its measured length on different CBCT-reconstruction images, but not between other subgroups. Conclusion: AL was a relatively common finding. The voxel size and fields of view of CBCT devices were adequate for assessing AL; however, a 2-mm safety margin from anatomical structures (such as the AL) could be recommended to be considered when using CBCT imaging. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVE: There is a risk of damage to the inferior alveolar nerve when extracting third molars. A variety of common imaging modalities, such as panoramic radiography (PR) and cone-beam computed tomography (CBCT), are recommended for examination prior to mandibular third molar surgery. The aim of this study was to compare the findings of panoramic radiography and CBCT in evaluating the relation between the root of the mandibular third molar and the inferior alveolar canal. METHODS: In this cross-sectional study, 75 panoramic and CBCT images were evaluated. Cases in panoramic radiography that were suspected of the relation between the root of the mandibular third molars and the inferior alveolar canal were collected. To determine the type of connection of apex and root canal, the samples were divided into 6 groups: normal, inferior alveolar canal path loss, canal path narrowing, sudden canal path change, radiolucent band over the roots, and root curvature. Cases in the panoramic radiograph that were suspected of root contact with the canal were examined by the CBCT in terms of the position of the canal relative to the tooth (buccal or lingual or middle of the root - upper or lower) and the type of connection (whether the tooth is connected to the canal). FINDINGS: In panoramic findings, 23 cases (30.7%) were normal, 19 cases (25.3%) showed canal path loss, 9 cases (12%) canal path narrowing, 5 cases (6.7%) sudden canal path change, 3 cases (4%) radiolucent band over the roots and 16 cases (21.3%) showed root curvature. According to CBCT findings, the position of the canal relative to the root apex was lingual in 39 cases (52%) and there was connection between the mandibular canal and the third molar in 39 cases (78.7%). There was no significant relationship between panoramic radiographic and CBCT findings and only in two cases of specific radiolucent band over the roots, there was a complete agreement between panoramic and CBCT findings. CONCLUSION: Based on the results of this study, if a radiolucent band is observed on the root of the mandibular molars or a sudden change is observed in the canal path, panoramic radiography can be used to detect the relation between the inferior alveolar canal and the root of the third molars.

Background and Objective: Knowing the position of the inferior alveolar canal and mental foramen is very important in periapical surgeries, administration of local anesthesia and implantation. The aim of this study is to compare the position and view of the inferior alveolar canal and mental foramen in panoramic radiography and CBCT images. Methods: In this cross-sectional study, concurrent panoramic radiography and CBCT images of patients who visited a private radiology clinic for one year were examined. In panoramic radiographs, the indices of canal visibility, mental foramen visibility, proximity of mental foramen to mandibular premolar teeth, canal diameter, mental foramen diameter and distance from mental foramen to alveolar crest were examined. Then all these cases were evaluated and compared in CBCT radiographs (as gold standard). Findings: In this study, concurrent CBCT and panoramic radiographs of 41 patients including 23 men (56.1%) and 18 women (43.9%) with a mean age of 51±13 years were analyzed. The mean values of variables of inferior alveolar canal diameter and distance from mental foramen to alveolar crest in panoramic images were significantly higher than CBCT images (p<0.001). The average diameter of mental foramen in panoramic images (3.9±1.3) was lower than CBCT images (4.2±1.3), but the difference was not significant (p=0.074). Conclusion: Based on the results of this study, although panoramic radiography can be used in routine treatments and general examination of the mandible, it is necessary to use the CBCT technique in dental practices that require higher accuracy in terms of measurement. [ABSTRACT FROM AUTHOR]

Aim: The objective of this study was to correlate the preoperative radiological findings and intraoperative surgical findings during removal of impacted mandibular 3rd molar with respect to the inferior alveolar canal. Materials and Method: The prospective study design included 100 patients between the age group of 20 years and 50 years who visited the Department of Oral and Maxillofacial Surgery at Vydehi Institute of Dental Sciences and Research Centre, Whitefield, Bengaluru. A preoperative panoramic radiograph was taken and the parameters were assessed and a normal surgical protocol was followed to extract the impacted mandibular 3rd molar with intra-operative assessment as well. Results: Out of the 100 patients with definitive radiological signs showing close relation of the third molar to the mandibular canal who underwent surgical removal, only 12 patients presented with definitive clinical findings of the association. Conclusion: A true close relationship between the third molars and mandibular canal increases the risk of inferior alveolar nerve injury, and accurate evaluation of the relationship is essential to avoid the risk of surgery. The accuracy of the plain radiographs to diagnose an intimate relationship between the neurovascular bundle and the third molar root has its limitations, since only 12 of the 100 patients with positive radiological signs showed clinical evidence of involvement. Surgeons should be aware of the limitations of the radiographic markers of panoramic radiography and should consider more detailed imaging in more specific cases in which one or more radiographic marker is present. [ABSTRACT FROM AUTHOR]

Purpose: The shape and position of the inferior alveolar canal (IAC) are analyzed to effectively reduce the risk of iatrogenic injury based on cone‐beam computer tomography (CBCT). To assist dental clinicians to make better use of the IAC information, we propose an IAC segmentation method based on CBCT images. Methods: In this paper, CBCT images are first preprocessed by the Hounsfield unit values clipping and gray normalization. Secondly, based on the multi‐plane reconstruction (MPR) and curved surface reconstruction, the curved MPR image sets are generated by the smooth dental arch curve with a sampling distance of 1.00 pixels. Then, the K‐means clustering algorithm is used to cluster the texture parameters of the gray level‐gradient co‐occurrence matrix enhanced by the gradient directions to improve the image contrast of the IAC. Finally, the IAC edges are roughly segmented by the 2D line‐tracking method, and smoothed by the fourth‐order polynomial to obtain the final segmentation result. Results: Twenty‐one real clinical dental CBCT datasets were used to test the proposed method. The manual segmentation results of two specialized dental clinicians were used as quantitative evaluation criteria. The dice similarity index (DSI), average symmetric surface distance (ASSD), and mean curve distance (MCD) of the left IAC are 0.93 (SD = 0.01), 0.16 mm (SD = 0.05 mm), and 1.59 mm (SD = 0.25 mm), respectively; the DSI, ASSD, and MCD of the right IAC are 0.93 (SD = 0.02), 0.16 mm (SD = 0.05 mm), and 1.60 mm (SD = 0.30 mm), respectively. Conclusions: The proposed method provides an effective image enhancement and segmentation solution to analyze the shape and position of the IAC. Experimental results show that the relationships between the IAC and other structures can be accurately reflected in the panoramic images without superimposition and geometric distortion, and the smooth edges of the IAC can be segmented. [ABSTRACT FROM AUTHOR]

Abstract Aim Understanding the mental foramen (MF) position and prevalence and location of the anterior loop (AL) is important during clinical and surgical procedures close to the mental foramen to avoid damage to the neurovascular bundle. The current study was done to determine the location of the MF, its distance from the inferior border of the mandible, and prevalence of AL in Egyptian population using cone beam computed tomography (CBCT). Methods A retrospective analysis of CBCT images was done in this study. Images of Egyptian patients who have already been subjected to CBCT examination as part of their dental diagnosis and/or treatment planning were included according to the proposed eligibility criteria. Results This study showed that the most common location of the MF (43.8% on the left side and 67.9% on the right side) is located below the apex of the second premolar. The mean size of mental foramen showed a height of 3.32 mm in females, 3.60 mm in males, and a width of 3.41 mm in females and 3.59 mm in males. The mean value of distance from inferior border was 10.08 mm in females and 10.55 mm in males. Fifty-five percent of the cases showed presence of anterior loop. Conclusion These results are consistent with similar radiographic studies regarding size and location of MF and distances between MF and adjacent anatomic structures. The most common position of the MF is below the 2nd premolar. AL was found in more than half of the cases examined.

Objective: The aim is to evaluate the location and proximity of second and third molars roots to the inferior alveolar canal (IAC) and demographic factors associated with these proximities. Materials and Methods: Cone beam computed tomography scans were evaluated for 292 roots of 146 teeth from 40 patients. A radiologist read, measured, and evaluated the vertical and horizontal positions of the roots of the second and third molars in relation to the IAC. Results: No significant differences were found between the third molar roots and neighboring second molar roots in the closeness to the IAC. The most common horizontal relation was “roots above IAC” (54%) followed by “roots lingual to IAC” (41.78%), “roots buccal to IAC” (3.42%), and “IAC between the roots” (0.68%). No significant differences in second and third molar roots and their contrasting teeth in the proximity to IAC. The older age group had significantly higher vertical measurements between third molar roots and IAC. There were significantly larger vertical measurements in the right third molar roots to IAC in males than females. Conclusions: These anatomical relationships are important clinical knowledge to avoid potential surgical injury to the inferior alveolar nerve.

Background and objective: Accurate understanding of the anatomy of the inferior alveolar nerve (IAN) and its relation with anatomical landmarks of mandibular molar teeth can reduce the risk of unwanted injuries to the IAN during implant placement. Methods: 44 CBCTs of patients,who have been reffered to the private oral and maxillofacial radiology center, were examined by a radiologist on the axial, sagittal and coronal planes. Then, the distances between mandibular canal and buccal cortex (BN) and lingual cortex (LN), buccolingual width of the mandibular canal (BL), and the distances between the canal and apex of the first molar (M1N) and second molar of mandible (M2N) were obtained from cross-sectional images. Data were analyzed using SPSS17 software and Kolmogorov-smirnov and Mann-whitney test. Results: 21 males and 23 females aged 20 to 50 years old (mean age: 37.8±7.52) were examined. The mean intervals in the regions of first molar in the right and left sides were BN: 4.03,4.06 mm, LN: 2.10,2.58 mm, BL: 2.20,2.20 mm, and M1N: 5.77,5.78 mm and in the second molar region, on the right and left sides were BN: 5.21,5.20 mm, LN: 1.95,1.80 mm and BL: 2.30,2.20 mm and M2N: 3.85,3.55 mm, respectively. There was a significant difference in the mean buccolingual width of mandibular canal in both sides in the region of first molar and left side in the region of second molar between two genders. (P=0.009, P=0.019, P=0.045). Other measurements were not significantly different between two genders (P>0.05). The age range of patients had no effect on any of the distances and measurements (P>0.05). Conclusion: buccolingual width of mandibular canal in both sides in the region of first molar and left side in the region of second molar was associated with gender.

Various endodontic interventions often lead to iatrogenic damage to the inferior alveolar nerve present in the inferior alveolar canal (IAC). The purpose of the present study was to analyze the relationships of IAC with the root apices of mandibular teeth and with the mandibular cortical plates. Materials: 116 cone beam computed tomography (CBCT) scans were examined and the shortest distance of IAC with the root apices of mandibular canines, premolars and molars, and with cortical plates was analyzed. The data were statistically analyzed using SPSS. Results: The shortest mean distance between IAC and lingual cortical plate (LCP) was found in the third molar area, and between IAC and buccal cortical plate (BCP) in the second premolar area. A high incidence of 60% direct communication (DC) was present in mandibular second molars; 38% in mandibular third molars; 13% in mandibular second premolars; 12% in mandibular first molars; and 1% in mandibular first premolars. Conclusion: Anteriorly, IAC was found to be significantly present in close approximation to the roots of mandibular canines. Posteriorly, IAC was found to be in significant proximity to the distal roots of mandibular second molars.

A recent study found that the mandibular canal might be preferably called the inferior alveolar canal in recent publication years, certain journal categories, countries and departments with which the authors were affiliated. The canal can also be called the inferior dental canal that was not included in that study. This bibliometric analysis was conducted to evaluate the entire relevant literature, and to investigate if inferior alveolar canal was trending over the years. The Web of Science Core Collection electronic database was searched to identify publications exclusively mentioning mandibular canal, inferior alveolar canal, inferior dental canal, and publications mentioning them in combinations. Publication year, country of contributing authors, journal category, journal title, and citation count were recorded for the resultant publications. There were 1152 publications analyzed. Mandibular canal has always been the dominating term since the 1990s, whereas inferior alveolar canal seemed to become slightly more popular in the 2010s than in the past. Journals from dentistry, surgery, radiology, anatomy, and medicine all showed a preference towards mandibular canal. Leading dental surgery journals had a higher ratio of inferior alveolar canal usage than their dental radiology counterparts. Top 20 countries showed a preference towards mandibular canal except Saudi Arabia, which had 57.7 % of publications using inferior alveolar canal exclusively. Publications mentioning mandibular canal, inferior alveolar canal, and inferior dental canal did not differ in averaged citation count. The term mandibular canal was still dominating in all academic fields. The term inferior alveolar canal showed increased usage in the 2010s without an increasing trend. The argumentation of renaming mandibular canal as inferior alveolar canal has yet to accumulate considerable traction. [ABSTRACT FROM AUTHOR]

Background and objectives: The retromolar canal is an anatomical variant that needs consideration in local anesthesia and surgical procedures involving the retromolar area. Complications such as local anesthetic insufficiency, a sensory deficit, hemorrhage and traumatic neuroma may arise in the absence of recognition of these variants. The aim of this study is to determine the prevalence and course of retromolar canal in the Iranian population. Methods: This study is a descriptive cross sectional study. The cross sectional sagittal and three dimensional images from volumetric CBCT. data of 270 patients were reconstructed using on demand imaging analysis software. Retromolar canals were classified into two types according to the courses. The width and location (distance from the third molar) of retromolar canals were evaluated. Results were analyzed with SPSS 20 software and were assessed using the t_test and chi_square test. Results: Retromolar canal was observed in 9/25 % of patients. The mean width of the retromolar foramen was 1/43 mm, and the mean distance from anterior border of retromolar foramen to the distal CEJ of the second molar was 13/33 mm. Conclusion: The prevalence of retromolar canals in the Iranian population was lower than that was reported in previous studies. It can be observed in 9/25 % of Iranian patients. Damage to the retromolar canal may be unavoidable during surgical procedures may result in paresthesia, excessive bleeding, postoperative hematoma, or traumatic neuroma. Therefore, the clinician must pay particular attention to the identification of a retromolar canal by preoperative radiographic examination and additional CBCT scanning is recommended.

BACKGROUND AND OBJECTIVE: There is a risk of damage to the inferior alveolar nerve when extracting third molars. A variety of common imaging modalities, such as panoramic radiography (PR) and cone-beam computed tomography (CBCT), are recommended for examination prior to mandibular third molar surgery. The aim of this study was to compare the findings of panoramic radiography and CBCT in evaluating the relation between the root of the mandibular third molar and the inferior alveolar canal. METHODS: In this cross-sectional study, 75 panoramic and CBCT images were evaluated. Cases in panoramic radiography that were suspected of the relation between the root of the mandibular third molars and the inferior alveolar canal were collected. To determine the type of connection of apex and root canal, the samples were divided into 6 groups: normal, inferior alveolar canal path loss, canal path narrowing, sudden canal path change, radiolucent band over the roots, and root curvature. Cases in the panoramic radiograph that were suspected of root contact with the canal were examined by the CBCT in terms of the position of the canal relative to the tooth (buccal or lingual or middle of the root - upper or lower) and the type of connection (whether the tooth is connected to the canal). FINDINGS: In panoramic findings, 23 cases (30.7%) were normal, 19 cases (25.3%) showed canal path loss, 9 cases (12%) canal path narrowing, 5 cases (6.7%) sudden canal path change, 3 cases (4%) radiolucent band over the roots and 16 cases (21.3%) showed root curvature. According to CBCT findings, the position of the canal relative to the root apex was lingual in 39 cases (52%) and there was connection between the mandibular canal and the third molar in 39 cases (78.7%). There was no significant relationship between panoramic radiographic and CBCT findings and only in two cases of specific radiolucent band over the roots, there was a complete agreement between panoramic and CBCT findings. CONCLUSION: Based on the results of this study, if a radiolucent band is observed on the root of the mandibular molars or a sudden change is observed in the canal path, panoramic radiography can be used to detect the relation between the inferior alveolar canal and the root of the third molars. [ABSTRACT FROM AUTHOR]

Context: Choosing an imaging source, which provides minimum radiation exposure to the patient, to facilitate surgical removal of impacted mandibular third molars (MTMs), thereby avoiding unwanted neurological complications. Aim: The aim of the study was to assess the efficacy of digital volume tomography (DVT) in evaluating the position of inferior alveolar canal (IAC) in relation to impacted MTMs and comparing it with conventional radiography (CR) in a subset of the Indian population. Materials and Methods: Four experienced observers assessed two groups: 33 DVT and 33 CR images, for the position of root-tips of impacted MTM in the proximity to IAC, in both vertical and horizontal planes. The diagnostic information was compared in both the groups. Statistical Analysis: Chi-square test, Mann–Whitney U-test, and Kappa statistics were used. Results: Comparison between DVT and CR revealed no statistically significant variation in assessing relationship in the vertical plane. There was, however, a significant difference between the groups, while comparing the diagnostic information for the horizontal dimension, for both the mesial and the distal roots, with an advantage for DVT (P < 0.05 for both mesial and distal roots). Conclusion: DVT is highly accurate in predicting neurovascular bundle exposure. It is indispensable for preoperative evaluation of impacted MTM.

Objective: The aim is to evaluate the location and proximity of second and third molars roots to the inferior alveolar canal (IAC) and demographic factors associated with these proximities. Materials and Methods: Cone beam computed tomography scans were evaluated for 292 roots of 146 teeth from 40 patients. A radiologist read, measured, and evaluated the vertical and horizontal positions of the roots of the second and third molars in relation to the IAC. Results: No significant differences were found between the third molar roots and neighboring second molar roots in the closeness to the IAC. The most common horizontal relation was "roots above IAC" (54%) followed by "roots lingual to IAC" (41.78%), "roots buccal to IAC" (3.42%), and "IAC between the roots" (0.68%). No significant differences in second and third molar roots and their contrasting teeth in the proximity to IAC. The older age group had significantly higher vertical measurements between third molar roots and IAC. There were significantly larger vertical measurements in the right third molar roots to IAC in males than females. Conclusions: These anatomical relationships are important clinical knowledge to avoid potential surgical injury to the inferior alveolar nerve. [ABSTRACT FROM AUTHOR]

Aim: Understanding the mental foramen (MF) position and prevalence and location of the anterior loop (AL) is important during clinical and surgical procedures close to the mental foramen to avoid damage to the neurovascular bundle. The current study was done to determine the location of the MF, its distance from the inferior border of the mandible, and prevalence of AL in Egyptian population using cone beam computed tomography (CBCT). Methods: A retrospective analysis of CBCT images was done in this study. Images of Egyptian patients who have already been subjected to CBCT examination as part of their dental diagnosis and/or treatment planning were included according to the proposed eligibility criteria. Results: This study showed that the most common location of the MF (43.8% on the left side and 67.9% on the right side) is located below the apex of the second premolar. The mean size of mental foramen showed a height of 3.32 mm in females, 3.60 mm in males, and a width of 3.41 mm in females and 3.59 mm in males. The mean value of distance from inferior border was 10.08 mm in females and 10.55 mm in males. Fifty-five percent of the cases showed presence of anterior loop. Conclusion: These results are consistent with similar radiographic studies regarding size and location of MF and distances between MF and adjacent anatomic structures. The most common position of the MF is below the 2nd premolar. AL was found in more than half of the cases examined. [ABSTRACT FROM AUTHOR]

Background Inferior alveolar nerve injury is the most serious complication of impacted lower third molar surgery. Objectives This study aims to optimize surgical procedure to safely remove wisdom tooth in contact or near the inferior alveolar canal and estimate the incidence of nerve injury in such cases. Methods and Methods this prospective controlled clinical study was implemented in Specialized Dental Center from February 2018 to May 2019. The sample was composed of 100 patients divided into two groups according to the distance of root apex from the inferior alveolar canal (the predictive variable), For the study group, the root apex is in contact or = 1mm from the inferior alveolar canal (buccal, lingual, or above the canal or canal between roots). For the control group the distance > 1mm. The primary outcome variable was inferior alveolar nerve injury after surgery. Another study variable was nerve recovery. Descriptive and bivariate statistics were computed and the P-value was set at .05. Results The study group involves 40 patients (18 males, 22 females) with a mean age of 23.5. The Control group involves 60 patients (26 males, 34 females) with a mean age of 24.5. There was a non-significant association between the distance of root apex to the inferior alveolar canal and paresthesia at p-value <.05 as revealed by fisher's exact test (p=.061). Conclusion The results of this study suggest that surgical removal of wisdom teeth with a close relation to the inferior alveolar canal is a safe procedure when specific precautions and techniques are performed. [ABSTRACT FROM AUTHOR]

The aim of this ex vivo study was to compare the diagnostic performances of panoramic radiography and cone beam computerized tomography (CBCT) in detecting implant-related injuries of the inferior alveolar canal. Monocortical bone windows were created in 60 fresh sheep hemimandibles, the inferior alveolar canals were revealed and 120 dental implants were inserted. Three types of injuries, described as pilot drill damage (PDRILL), collapsing of the superior border of the canal (COLL), penetration of the implant tip into the canal (PENET) and one control group, were simulated. Standard (PANO) and dentition mode panoramic (PANO-DENT) images as well as CBCT data presented as multiplanar reconstruction (MPR) and cross-sectional (CROSS) views were evaluated by 6 observers who had also expressed their level of confidence to their final diagnosis. Intra- and interobserver agreement scores were rated good. The area under the curve (AUC) values and the confidence scores for CROSS and multiplanar reformation (MPR) views were both significantly higher than those of PANO and PANO-DENT (P, .05 for each) in PDRILL group. In COLL group, observers showed less confidence to PANO and PANODENT compared to CROSS and MPR techniques (P, .05 for each). No other significant differences were found. Within the limits of this experimental study, it can be suggested that the standard and dentition modes of panoramic radiography can be as effective as CBCT in the detection of penetrating and collapsing injuries, but multiplanar and cross-sectional views of the CBCT are more accurate than panoramic radiography in the detection of pilot drill injuries in sheep mandible. [ABSTRACT FROM AUTHOR]

Introduction: The inferior alveolar nerve (IAN) is one of the most important vital structures found in the mandible, knowing the precise location of the mandibula canal is helpful to decrease the incidence and avoid the injury to the (MC).Material & Method: 30 males & 30 females were selected from the data of the (CBCT) stored in the computer joined to the device and the measurements were taken as follow “ The first section in trans-axial view after mental foramen, where the loop of mandibular canal is formed, was selected as point A and interludes of 10 mm were selected for subsequent measurements (respectively, points B,C,D). On these sections, the shortest linear distances (in mm) from the most lingual aspect of the canal to the outer lingual cortical plate of the mandible(L) and from the mandibular canal to the inferior border of mandibular body(I) were measured. Furthermore, the minimum distance between the buccal cortices and the mandibular canal(B) were evaluated” as in (Fig. 1). Using SPSS software Version 15 the data that had been obtained was analyzed. Results: The results had been showed that there is no significant difference in measurements were taken between males and females groups in the measurement of the distance of the inferior dental canal to the buccal cortical and in the measurement of the distance of the inferior dental canal to lingual cortical bone of the mandible, only in the measurement of the (IDC) to inferior border of the mandible there was a significant difference in only one pointConclusion: It can be concluded from this study that the information can be obtained by the (CBCT) about the location of the (MC) can helpful for the surgeons to avoid damage to (MC) throughout surgical procedures in the mandible, and those information can give good overview and conception for course of the (MC) through the mandible. [ABSTRACT FROM AUTHOR]

The mandibular canal is considered one of the crucial structures in the mandible, so that knowledge of its location is one of the most important challenges in dental practice. Therefore, maintaining the integrity of the mandibular canal is a significant point for many clinicians who operate on or near this structure, for avoiding injury of the vital structures, especially the inferior alveolar nerve. The present study aimed at evaluating the inferior alveolar canal (IAC) proximity to the mandibular-thirdmolars by reviewing the previous studies of interest issued in this field. Certain radiographic marks have been applied to indicate the proximity level of IAC to the mandibular 3rd-molar roots on CBCT or panoramic images. In addition, the depth level and angulation of these molars to IAC had been reviewed. The radiographic marks here applied were considered valuable to some extent to identify IAC proximity to the roots of the mandibular third molars. [ABSTRACT FROM AUTHOR]

Aims: To investigate the distances between inferior alveolar canal (IAC) to both mesial and distal roots of mandibular second molar (M2) and inferior mandibular cortex. Materials and Methods: This retrospective study was carried out on 110 patients (50 women and 60 men) aged between 20 and 50 years. Each patient took one panoramic image and one digital intraoral image for the right side at second molar area. Patients were evaluated by gender and age (coterie I = 54 and coterie II = 56). Data were analyzed by using the Statistical Package for the Social Sciences Statistics software, version 22.0 (IBM, Chicago, Illinois), and the mean values were compared using the compare means test. Results: The results showed no significant differences at P > 0.05 between men and women in the distances of M2 roots and mandibular cortex to IAC by both digital techniques. However, the roots of M2 of women (2.7 and 1.8 mm by digital panoramic, 2.6 and 2 mm by digital intraoral image) and of those aged less than 35 years (3.1 and 2.45 mm by digital panoramic, 3.1 and 2.56 mm by digital intraoral image) were near to the IAC. Conclusion: Preoperative investigations to know the degree of vicinity of roots of M2 and lower jaw canal by using of digital radiographic imaging (intraoral and panoramic) depending on their properties (image enhancement, measuring tools, and updating data) have high values to avoid a complications such as distress and numbness after dental procedures by direct damage or pushed toxic dental materials in this tunnel. [ABSTRACT FROM AUTHOR]

The study aimed to stratify the risk of inferior alveolar nerve injury (IANI) after lower third molar (LM3) surgery with a scoring system using identified predictive factors based on cone-beam computed tomography (CBCT) images. In a case–control study, the primary outcome was IANI occurrence. The control group included randomly selected patients without IANI. Predictor variables included patient demographics, surgical situations, Pell–Gregory classification, and inferior alveolar canal (IAC)-associated factors on CBCT. Study variables were analyzed using logistic regression models. Risk stratification was assessed by a scoring system that was constructed using independent predictors. The 858 patients who underwent LM3 surgery (1177 teeth) after CBCT scan were divided into case (25 patients, 2.9%, 27 teeth) and control (235 patients, 300 teeth) groups. In the multivariate model, lingual/inter-radicular position of IAC [odds ratio (OR) 7.21; P < 0.001; assigned score, 2], multiple roots closed to the IAC with cortical perforation (OR 3.72; P = 0.015; 1), and age > 30 years (OR 4.99; P = 0.008; 2) were associated with an increased IANI-risk. The IANI-risk scoring system could be stratified into low- and high-risk groups at a cutoff score of 3 (sensitivity, 68.0%; specificity, 90.6%; positive predictive value, 17.8%; positive likelihood ratio, 7.23). In conclusion, the high-risk group of IANI after LM3 surgery corresponded to individuals with multiple factors: lingual/inter-radicular IAC position to LM3, multiple roots with perforated IAC, and increased age (> 30 years). Raising awareness of the higher probability for IANI is needed for patients with multiple aforementioned factors. [ABSTRACT FROM AUTHOR]

Background and objective: Extraction of an impacted mandibular third lower molar tooth is one of the common surgical procedures that may lead to the damage of inferior alveolar nerve due to roots proximity to the mandibular canal. This study aimed to know the relative relationship and proximity of the mandibular third molar roots to the inferior alveolar canal in relation to gender, age, depth of impaction, relation with ramus, and type of angulation of the impacted tooth in Kurdistan population. Methods: A sample of 366 digital panoramic radiographs of patients with impacted mandibular third molar was studied. Panoramic radiographic signs images were evaluated for the presence of root contact with the superior border of the mandibular canal, darkening of the roots apex, deflected roots, narrow root, superimposition of the canal, interruption of the white line, diversion of the inferior alveolar canal, and narrowing of the inferior alveolar canal. The depths of impaction, relation with ramus, and type of angulation were also studied. Results: Significant relation of the proximity of the mandibular third molar roots to the inferior alveolar canal with the gender (P = 0.001) and age (P