Comparison of data mining algorithms for sex determination based on mastoid process measurements using cone-beam computed tomography

Purpose@#The mastoid region is ideal for studying sexual dimorphism due to its anatomical position at the base of the skull. This study aimed to determine sex in the Iranian population based on measurements of the mastoid process using different data mining algorithms. @*Materials and Methods@#This retrospective study was conducted on 190 3-dimensional cone-beam computed tomographic (CBCT) images of 105 women and 85 men between the ages of 18 and 70 years. On each CBCT scan, the following 9 landmarks were measured: the distance between the porion and the mastoidale; the mastoid length, height, and width; the distance between the mastoidale and the mastoid incision; the intermastoid distance (IMD); the distance between the lowest point of the mastoid triangle and the most prominent convex surface of the mastoid (MF); the distance between the most prominent convex mastoid point (IMSLD); and the intersecting angle drawn from the most prominent right and left mastoid point (MMCA). Several predictive models were constructed and their accuracy was compared using cross-validation. @*Results@#The results of the t-test revealed a statistically significant difference between the sexes in all variables except MF and MMCA. The random forest model, with an accuracy of 97.0%, had the best performance in predicting sex. The IMSLD and IMD made the largest contributions to predicting sex, while the MMCA variable had the least significant role. @*Conclusion@#These results show the possibility of developing an accurate tool using data mining algorithms for sex determination in the forensic framework.

Common conditions associated with displacement of the inferior alveolar nerve canal: A radiographic diagnostic aid

PURPOSE: This study reviewed the common conditions associated with displacement of inferior alveolar nerve canal. MATERIALS AND METHODS: General search engines and specialized databases including Google Scholar, Pub Med, Pub Med Central, Science Direct, and Scopus were used to find relevant studies by using keywords such as “mandibular canal”, “alveolar canal”, “inferior alveolar nerve canal”, “inferior dental canal”, “inferior mandibular canal” and “displacement”. RESULTS: About 120 articles were found, of which approximately 70 were broadly relevant to the topic. We ultimately included 37 articles that were closely related to the topic of interest. When the data were compiled, the following 8 lesions were found to have a relationship with displacement of mandibular canal: radicular/residual cysts, dentigerous cyst, odontogenic keratocyst, aneurysmal bone cyst, ameloblastoma, central giant cell granuloma, fibrous dysplasis, and cementossifying fibroma. CONCLUSION: When clinicians encounter a lesion associated with displaced mandibular canal, they should first consider these entities in the differential diagnosis. This review would help dentists make more accurate diagnoses and develop better treatment plans according to patients' radiographs.

Common conditions associated with mandibular canal widening: A literature review

PURPOSE: The aim of this study was to review the common conditions associated with mandibular canal widening. MATERIALS AND METHODS: General search engines and specialized databases including Google Scholar, PubMed, PubMed Central, Science Direct, and Scopus were used to find relevant studies by using the following keywords: “mandibular canal,” “alveolar canal,” “inferior alveolar nerve canal,” “inferior dental canal,” “inferior mandibular canal,” “widening,” “enlargement,” “distension,” “expansion,” and “dilation.” RESULTS: In total, 130 articles were found, of which 80 were broadly relevant to the topic. We ultimately included 38 articles that were closely related to the topic of interest. When the data were compiled, the following 7 lesions were found to have a relationship with mandibular canal widening: non-Hodgkin lymphoma, osteosarcoma, schwannoma, neurofibroma, vascular malformation/hemangioma, multiple endocrine neoplasia syndromes, and perineural spreading or invasion. CONCLUSION: When clinicians encounter a lesion associated with mandibular canal widening, they should immediately consider these entities in the differential diagnosis. Doing so will help dentists make more accurate diagnoses and develop better treatment plans based on patients' radiographs.

Validity of panoramic indices to evaluate the association of bone mineral density with morphology of the mandible in osteoporotic patients

Objective: Osteoporosis is the most common metabolic disease of the bone decreasing bone mineral density [BMD] particularly in postmenopausal women. On the other hand, panoramic radiography has several applications in dentistry. It appears that by calculating some indices on panoramic radiographs, we may be able to predict the risk of osteoporosis in high-risk individuals. The present study was conducted to determine the correlation of skeletal pattern of bone and the morphology of the mandible in osteoporotic patients presenting to the Osteoporosis Clinic of Khatamolanbia Hospital and Imam Khomeini Dental Clinic in Yazd

Methods: This descriptive, analytical, cross-sectional study was conducted on 70 women aged over 45 years, whom were selected from the above-mentioned centers. The gonialangle [GA], gonial index [GI], antegonial angle [AA], mental index [MI], antegonial index [AI] and antegonial depth [AD] were calculated on panoramic radiographs of patients and their BMD was measured in the lumbar area and femoral areas using dual X-ray absorptiometry [DXA]. The correlation of panoramic indices with BMD was assessed using Spearman and Pearson's correlation tests. The difference in BMD values in different morphological patterns of the inferior cortex of the mandible was analyzed by Student t-test and in different thicknesses of the cortex using one-way ANOVA

Results: The morphology of the inferior cortex was C1 in 62.9% and C2 in 37.1%. The cortex was thin in 24.3%, moderately thick in 32.9% and thick in 42.9%. Lumbar BMD was 0.92 [0.14] and 0.75 [0.15] g/cm2, in C1 and C2, respectively [p<0.001]. Femoral BMD was 0.81 [0.13] and 0.66 [0.09] g/cm2 in C1 and C2, respectively [p<0.001]. No significant association was found between GI, AI, GA, AA and AD [based on the estimates made on panoramic radiographs] with the BMD [based on DXA estimates]

Conclusion: Use of mandibular cortex indices on panoramic radiographs may be efficient for assessment of osteoporosis. However, further multicenter studies on larger sample sizes are required

effect of intra-canal posts on diagnostic accuracy of cone beam computed tomography and digital radiography in detection of vertical root fractures

Objective: Diagnosis of vertical root fractures [VRFs] is critical in endodontics. Cone Beam Computed Tomography [CBCT] has significantly enhanced image quality compared to digital radiography [DR] and greatly aids the diagnosis of VRFs but, metal artifacts has remained as a problem in VRF detection. This study evaluated the effect of intra canal posts on the diagnostic accuracy of CBCT and DR for detection of VRFs

Methods: In this experimental in vitro study eighty extracted human premolar teeth were cut at the cement-enamel junction .After root canal preparation, the casting posts were made. Samples were randomly divided into 2 groups of 40; group one with induced fracture and group 2 as the control group. Radiographs were taken for all specimens with and without posts with both imaging systems. Three observers assessed the presence or absence of VRF. Accuracy of the two imaging systems and the effect of post on VRF detection were assessed, using two-way ANOVA test and inter observer coefficient agreement was calculated

Results: Absolute diagnostic sensitivity and specificity of CBCT and absolute sensitivity of DR in the group with intracanal posts were significantly lower than those in the group without posts [p=0.023, p=0.034 and p=0.034 respectively]. Absolute specificity of DR in the group with posts was significantly higher than that of the CBCT [p=0.014]. The absolute and complete specificity of CBCT in the group without posts was significantly higher than those of DR [p=0.024, p=0.04]. No statistically significant difference was found in inter observer agreement coefficient in presence or absence of posts or between the two imaging systems [p=0.119]

Conclusion: Intra canal posts decreased the diagnostic accuracy of CBCT and DR for detection of VRFs and this reduction was greater in CBCT. However, absolute specificity of DR in the group with posts was significantly higher than that of the CBCT, where as CBCT images of teeth without posts still had higher diagnostic accuracy than DR

Evaluation of alveolar crest bone loss via premolar bitewing radiographs: presentation of a new method

PURPOSE: This study aimed to assess the interdental bone level in premolar bitewing radiographs while retracting the cheeks. METHODS: Seventy-two horizontal bone defects were created on dried mandibles and maxillae. The distance from the bone level to the cement-enamel junction of premolars was detected by a modified digital caliper (considered the gold standard). The reliability of all radiographs was assessed by intraclass correlation coefficient (ICC), and the validity was compared to the gold standard using the analysis of variance test. P-values less than 0.05 were considered statistically significant. RESULTS: This study showed that the reliability of radiographs without a cheek simulator and with 0.16 second exposure time was significantly higher than that of the two other groups (ICC=0.96 compared to 0.93 and 0.88, respectively). The results from the radiographs without a cheek simulator and with 0.16 second exposure time were more similar to the gold standard measures than those of the two other groups, although the difference was not statistically significant. CONCLUSIONS: Retracting the buccal soft tissue plays an important role in increasing the accuracy of radiographs in detecting the interdental alveolar bone level and produces more accurate results than increasing the exposure time, although it does not have a significant role in reliability of results.