Evaluation of Mental Foramen and Mandibular Canal Course and Location in an Emirati Subpopulation.

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

Artificial intelligence-based automated preprocessing and classification of impacted maxillary canines in panoramic radiographs.

OBJECTIVES: Automating the digital workflow for diagnosing impacted canines using panoramic radiographs (PRs) is challenging. This study explored feature extraction, automated cropping, and classification of impacted and nonimpacted canines as a first step. METHODS: A convolutional neural network with SqueezeNet architecture was first trained to classify two groups of PRs (91with and 91without impacted canines) on the MATLAB programming platform. Based on results, the need to crop the PRs was realized. Next, artificial intelligence (AI) detectors were trained to identify specific landmarks (maxillary central incisors, lateral incisors, canines, bicuspids, nasal area, and the mandibular ramus) on the PRs. Landmarks were then explored to guide cropping of the PRs. Finally, improvements in classification of automatically cropped PRs were studied. RESULTS: Without cropping, the area under the curve (AUC) of the receiver operating characteristic (ROC) curve for classifying impacted and nonimpacted canine was 84%. Landmark training showed that detectors could correctly identify upper central incisors and the ramus in ∼98% of PRs. The combined use of the mandibular ramus and maxillary central incisors as guides for cropping yielded the best results (∼10% incorrect cropping). When automatically cropped PRs were used, the AUC-ROC improved to 96%. CONCLUSIONS: AI algorithms can be automated to preprocess PRs and improve the identification of impacted canines.

The C-shaped root canal systems in mandibular second molars in an Emirati population.

Our study aimed to describe the root and canal morphology of mandibular second molars in Emirati population and to study the prevalence and types of morphological change in C-shaped canal configuration along the root length in an effort to describe C-shaped molars as a unit. Cone beam computed tomography (CBCT) scans of Emirati patients were analyzed in multiple plans and root and canal configuration of mandibular second molars were evaluated. Moreover, specific types of morphological change in C-shaped canal configuration along root length were studied and reconstructed using 3D reconstruction software. A total of 508 mandibular second molars were evaluated. Among the non-C-shaped mandibular second molars, two separate roots were the most prevalent root morphology (78.3%). The mesial root's most common root canal configuration was Vertucci Type II (46.5%), and in the distal root, Vertucci Type I (90.5%). The prevalence of C-shaped mandibular second molars was 17.9% and was significantly prevalent (P < 0.001) in females. Specific types of morphological change in C-shaped molars along the root length were observed and described for the first time, in which the most common types of morphological change were C1-C2-C3d (18%), C1-C3c-C3d (15.4%), C4-C3c-C3d (7.7%), and C3c-C3c-C3d (7.7%). This study showed wide variations in the root and canal morphology in mandibular second molars in Emirati population with a relatively high prevalence of C-shaped canal configuration (17.9%). Moreover, specific types of morphological change in C-shaped configuration were detected and described for the first time in this population.

Evaluation of root and canal morphology of maxillary permanent first molars in an Emirati population; a cone-beam computed tomography study.

BACKGROUND: The aim of this study was to analyze the root and canal morphology of the maxillary permanent first molars in an Emirati population using cone-beam computed tomography (CBCT). METHODS: Two hundred and sixty-one CBCT scans were acquired. The data were extracted and anonymized to remove all patient identifiers. Two observers (an endodontic resident and an endodontist) evaluated all scans on diagnostic quality monitors. RESULTS: The prevalence of a second mesiobuccal canal (MB2) was 80.1% in all examined samples. Type II Vertucci classification, was the most common canal configuration (59%) in the mesiobuccal root, followed by Types I (19.9%) and IV (15.3%), while Type III was the least common (5.7%). Types I, II, and IV were significantly more common in the 21-40-year age group (P < 0.001), while Type III was observed significantly more often in the < 20-year age group (P < 0.001). No significant effect of gender on the prevalence of Vertucci classification in the mesiobuccal root of maxillary first molars (P = 0.74) was found. Analysis of bilateral symmetry showed that 80% teeth had perfect bilateral symmetry, whereas 20% were asymmetrical. Type II canal configuration showed the highest prevalence of bilateral symmetry (48.7%), followed by Type I (15%) and Type IV (10%), while Type III showed the least prevalence of symmetry (3%). CONCLUSIONS: This was the first study to analyze the prevalence of MB2 canal in an Emirati population. Our results indicate high prevalence of MB2 (80.1%) and emphasize the importance of using advanced techniques to locate the MB2 canal.

Efficacy of Cone-Beam Computed Tomography in Evaluating Bone Quality for Optimum Implant Treatment Planning.

PURPOSE: This study examined (1) if cone-beam computed tomography (CBCT) can determine relative differences in bone mineral density distribution using clinical images of patients' mandibular bone and (2) if the relative differences can be used to detect the effects of sex and age on bone mineral density distribution. MATERIALS AND METHODS: Sixty-six clinical CBCT images from patients (36 females and 30 males) of 3 age groups (40, 50, and 60 years) were identified. Alveolar (AB) and basal cortical bone (CB) regions were digitally isolated. A histogram of gray levels, which are proportional to degrees of bone mineralization, was obtained from each region. Mean, variability (SD and coefficient of variation), and percentage differences of gray level parameters between AB and basal CBs were computed. RESULTS: Significant sex differences in gray level variability were observed within the postmenopausal age group (P < 0.042). CONCLUSION: These findings suggest that clinical CBCT images can be a valuable tool in providing information on bone quality, which is an important criterion for optimum planning for dental implant placement.

Split-Mouth Comparison of Splinted and Nonsplinted Prostheses on Short Implants: 3-Year Results.

PURPOSE: To compare splinted and individual restorations supported by short implants featuring an internal connection utilizing a split-mouth design. MATERIALS AND METHODS: Splinted and nonsplinted implant crowns were prospectively compared in 18 patients. After verifying the need for at least two consecutive implants bilaterally, computed tomography scans were made, virtual planning was done, and qualifying patients were enrolled. Implants were placed using a two-stage surgical approach. After 3 to 5 months, patients were randomly restored with splinted prostheses on their left or right side. Nonsplinted restorations were made for contralateral sides. Radiographs were taken at prostheses seating and yearly exams. Radiographic bone levels were analyzed and compared (SAS 9.4) to determine differences between splinted and nonsplinted implants. Complications such as screw loosening, screw breakage, or porcelain fracture were assessed at recalls. RESULTS: Eighteen patients (9 men and 9 women) with an age range from 49 to 76 years (mean = 56 years), received ≥ 4 implants in symmetrical posterior locations. Implants (n = 82) ranged in length from 6 to 11 mm with 70 implants ≤ 9 mm and 38 implants = 6 mm. At the time of this report, 3-year examinations and bone level comparisons were completed on 15 patients. One patient was lost to follow-up, one deviated from study protocol by smoking, and one was splinted on both sides due to repeated screw breakage. Screw loosening occurred in five patients on their nonsplinted side. These were 6-mm implants except for one patient. Porcelain chipping occurred for one patient on the splinted side. One 6-mm-length nonsplinted implant was lost after loading; this implant was successfully replaced after grafting. This patient had a total of six implants placed; ongoing bone level measurements included two pairs of implants only. For all implants combined, there was no significant difference (P > .05) at 1, 2, or 3 years for mean bone change around splinted and nonsplinted implants. However, length was identified as a significant factor (P = .0039). Further analysis revealed statistically significant differences between splinted and nonsplinted for 6-mm length implants at 24 (P = .0061) and 36 (P = .0144) months. A gain in mean bone level of 0.41 and 0.37 mm was observed for nonsplinted implants at 24 and 36 months compared with baseline. Bone levels for the splinted 6-mm implants were not statistically different from baseline measurements (P > .05). CONCLUSION: Results of this prospective 3-year study of splinted ipsilateral and nonsplinted contralateral implants in 15 patients show: (1) peri-implant bone levels around splinted and nonsplinted implants were not statistically different for implants greater than 6 mm in length; (2) nonsplinted 6-mm implants revealed a gain in bone at 24 and 36 months compared with baseline; (3) all screw loosening only occurred on the nonsplinted side for 5 of 15 patients; and (4) implant loss after loading occurred for one 6-mm nonsplinted implant.

Role of ultrasonography in differentiating facial swellings of odontogenic origin.

INTRODUCTION: Differentiating an acute, odontogenic facial swelling clinically as cellulitis or an abscess has not been thoroughly investigated in endodontics. It has been suggested in the medical and dental literature that the use of ultrasound may aid in differentiating cellulitis from an abscess. Therefore, if ultrasound were more accurate than a blind incision for drainage procedure in locating purulence, perhaps the outcome of the incision for drainage procedure would be beneficial in the resolution of odontogenic infections. The purpose of this prospective study was to compare clinical examination plus ultrasonography versus clinical examination alone in differentiating cellulitis from abscesses in patients with facial swelling of odontogenic origin. METHODS: Eighty-two emergency patients participated in this study. Each patient was examined and diagnosed by clinical examination and clinical examination plus ultrasonography. An incision for drainage procedure was performed, and a definitive diagnosis was recorded as cellulitis (no purulence) or an abscess (presence of purulence). RESULTS: With the incision for drainage procedure, cellulitis occurred 37% of the time and abscesses 63%. With clinical examination alone, a correct diagnosis was made 68% of the time. With clinical examination plus ultrasonography, a correct diagnosis was made 70% of the time. There was no statistically significant difference between the 2 examination methods. CONCLUSIONS: The addition of ultrasonography to a clinical examination did not significantly increase the number of correct diagnoses.

Evaluation of cone-beam computed tomography in the diagnosis of simulated small osseous defects in the mandibular condyle.

INTRODUCTION: In this study, we investigated the impact of defect size and scan voxel size on the accuracy of cone-beam computed tomography (CBCT) diagnoses of simulated condylar defects and assessed the value of orthodontic CBCT images typically scanned at lower settings (0.4-mm voxel size and full-size field of view) in diagnosing condylar erosion defects. METHODS: Cylindrical holes simulating condylar defects with varied diameters (≤2, 2-3, and >3 mm) and depths (≤2 and >2 mm) were created in 22 fresh pig mandibular condyles, with defect number and size per condyle and quadrant randomly determined. With the soft tissues repositioned, 2 CBCT scans (voxel sizes, 0.4 and 0.2 mm) of the pig heads were obtained from an i-CAT unit (Imaging Science International, Hatfield, Pa). Reconstructed CBCT data were analyzed independently by 2 calibrated, blinded raters using Dolphin-3D (Dolphin Imaging and Management Solutions, Chatsworth, Calif) for defect identification and localization and defect diameter and depth measurements, which were compared with physical diagnoses obtained from polyvinyl siloxane impressions. RESULTS: Identification and localization of simulated defects demonstrated moderate interrater reliability and excellent specificity and sensitivity, except for extremely small defects (both diameter and depth ≤2 mm) viewed with 0.4-mm scans, which had a significantly lower sensitivity (67.3%). Geometric measurements of simulated defects demonstrated good but not excellent interrater reliability and submillimeter inaccuracy for all defects. Receiver operating characteristic analyses demonstrated that the overall accuracy of diagnosing simulated condylar defects based on CBCT geometric measurements was fair and good for the 0.4-mm and 0.2-mm voxel-size scans, respectively. With the prevalence of condylar erosion defects in the patients considered, the positive predictive values of diagnoses based on 0.5-mm size (diameter or depth) cutoff points were near 15% and 50% for asymptomatic and symptomatic temporomandibular joints, respectively; the negative predictive values were near 95% and 90%, respectively. CONCLUSIONS: When using orthodontic CBCT images for diagnosing condylar osseous defects, extremely small (<2 mm) defects can be difficult to detect; caution is also needed for the diagnostic accuracy of positive diagnoses, especially those from asymptomatic temporomandibular joints.

Factors affecting the accuracy of buccal alveolar bone height measurements from cone-beam computed tomography images.

INTRODUCTION: The reasons for inaccuracies in alveolar bone measurement from cone-beam computed tomography (CBCT) images might be multifactorial. In this study, we investigated the impact of software, the presence or absence of soft tissues, the voxel size of the scan, and the regions in the jaws on buccal alveolar bone height measurements in pigs at an age equivalent to human adolescents. METHODS: Marker holes, apical to the maxillary and mandibular molar roots, and mesiodistal molar occlusal reference grooves were created in 6 fresh pig heads (12 for each jaw), followed by CBCT scans at 0.4-mm and 0.2-mm voxel sizes under soft-tissue presence and soft-tissue absence conditions. Subsequently, buccolingual sections bisecting the marker holes were cut, from which the physical alveolar bone height and thickness were measured. One blinded rater, using Dolphin (version 11.5 Premium; Dolphin Imaging, Chatsworth, Calif) and OsiriX (version 3.9; www.osirix-viewer.com) software, independently collected alveolar bone height measurements from the CBCT images. Differences between the CBCT and the physical measurements were calculated. The mean differences and the limit of agreement (LOA, ±1.96 SD) for every jaw, voxel-size, soft-tissue, and software condition were depicted. Each measurement was then assessed for clinical inaccuracy by using 2 levels of criteria (absolute differences between CBCT and physical measurements ≥1 mm, or absolute differences between CBCT and physical measurements ≥0.5 mm), and the interactions between soft-tissue and voxel-size factors for every jaw and software condition were assessed by chi-square tests. RESULTS: Overall, the mean differences between the CBCT and the physical measurements for every jaw, voxel-size, soft-tissue, and software condition were near 0. With all other conditions kept equal, the accuracy of the maxillary CBCT measurements was inferior (larger limit of agreement ranges and higher frequencies of clinical inaccuracy) to the mandibular measurements. The physical thickness of the maxillary alveolar crestal bone was less than 1 mm and significantly thinner than the mandibular counterparts. For every jaw and software condition, the accuracy of measurements from the 0.2-mm soft-tissue presence CBCT images was consistently superior (smaller limit of agreement ranges and lower frequencies of clinical inaccuracy) to those from the 0.4-mm soft-tissue presence, the 0.4-mm soft-tissue absence, and the 0.2-mm soft-tissue absence images; all showed similar accuracies. Qualitatively, the soft-tissue absence images demonstrated much brighter enamel and alveolar bone surface contours than did the soft-tissue presence images. CONCLUSIONS: At an adolescent age, the buccal alveolar bone height measured from the maxillary molar region based on 0.4-mm voxel-size CBCT images can have relatively large and frequently inaccurate measurements, possibly due to its thinness. By using 0.2-mm voxel-size scans, measurement accuracy might be improved, but only when the overlying facial and gingival tissues are kept intact.

Cone beam computed tomography in dental education: a survey of US, UK, and Australian dental schools.

Cone beam computed tomography (CBCT) is an excellent three-dimensional (3D) imaging modality. Traditional dental education has focused on teaching conventional (2D) imaging. The aims of this survey-based study were therefore to evaluate the incorporation of CBCT teaching in both the predoctoral/undergraduate (D.D.S./D.M.D./B.D.S.) and postgraduate/residency specialty training curricula in dental schools in the United States, the United Kingdom, and Australia. A nine-question survey form was electronically mailed to fifty-seven schools in the United States, sixteen schools in the United Kingdom, and seven schools in Australia. Fifty U.S. dental schools (89 percent), ten U.K. dental schools (62.5 percent), and one Australian dental school (14 percent) presently have CBCT equipment. The majority of responding schools do not include instruction in higher level use of this technology for undergraduate/predoctoral students, raising questions as to whether these students are adequately trained on qualification. Larger numbers of schools reported providing this training to residents in specialty programs. A similar trend was noticed in U.S., British, and Australian dental education. If general dentists are to be permitted to purchase and use CBCT equipment, inclusion of CBCT in dental education is an absolute requirement to prepare future dental practitioners to apply 3D imaging appropriately for diagnosis and treatment planning.

Cone-beam computed tomography for analyzing variations in inferior alveolar canal location in adults in relation to age and sex.

Previous studies have indicated that the relative position of the inferior alveolar canal and its mental and mandibular foramina in adults vary with age and show sexual dimorphism. Conceivably, these purported differences could be of forensic value for determining identity of human remains. This study was designed to determine the influence of age and sex on the relative position of inferior alveolar canal and its foramina in cone-beam computed tomography (CBCT) studies of adults. Existing CBCT studies of the maxillofacial region from dentate adult patients selected at random and ranging in age from 18 to 80 years (110 women and 55 men) were acquired, and the location of the inferior alveolar canal was assessed at three points: the mandibular foramen in axial view, the inferior alveolar canal in coronal view, and the mental foramen in coronal view. Measurements were also expressed for the mental foramen as the percentile position from the nearest superior bony crest to the inferior border; corresponding position of the mandibular foramen from the anterior to the posterior border of the mandibular ramus; and for the inferior alveolar canal at the level of first permanent molar from the nearest buccal bony surface to the lingual surface and from the superior alveolar crest to the inferior border. Regression analyses were performed on the variables with regard to the effects of age and sex. Most analyses resulted in no statistical significance (p<0.05). A few of the sex-specific traits demonstrated near-statistically significant effects; however, these characterizations generally resulted in a 1% or less change per age decade. Overall, the results demonstrated that the relative location of the inferior alveolar canal and associated foramina in adults remain fairly constant without regard to age and sex.

Cancellous osteoma of the maxillary tuberosity: case report.

The osteoma is a benign, bone-forming lesion that is not considered a true neoplasm. It almost exclusively affects the flat bones of the skull and face. Jaw lesions may cause facial deformity and impair oral function. Multiple osteomas may be associated with Gardner's syndrome. Clinically and radiographically, osteomas may need to be differentiated from other bone-forming lesions. This article describes a cancellous osteoma of the left maxillary molar and tuberosity area and differentiates it from other benign and malignant lesions, including the parosteal osteosarcoma.

Postmortem dental radiography.

Comparison of postmortem and antemortem dental radiographic films or digital images is a common procedure for establishing identity of human remains. This article describes some problems with producing postmortem dental radiographs in a medical examiner setting and gives methods for circumventing these difficulties. Resection of the jaws, when permitted, significantly simplifies the postmortem radiographic technique. When producing an actual postmortem panoramic dental radiograph (orthopantomogram) from a dry skull, stabilization of the specimen for exposure by the moving beam source may be accomplished simply by placing the specimen upside down on an anthropologist's skull ring. Image "burnout" in the anterior segment, which results from absence of the tissues of the neck, may be avoided by appropriate placement of radiodense objects such as "zippered" plastic bags filled with water or other fluid material, freezer gel packs, or a block of self-polymerizing acrylic. These methods may increase future postmortem dental radiography efficiency.