Injury Risk Estimation in Mandible-Related Surgical Procedures: A CBCT Study Based on Vital Interforaminal Anatomical Structures.

The mandibular interforaminal region has been considered safe for surgical procedures; nevertheless, the risk of injury to neurovascular structures, such as the mental foramen (MF) and its related structures (anterior loop [AL] and lingual foramina [LF]) should not be overlooked. The study aimed to evaluate the relative risk of injury to these structures during surgical procedures in the anterior region of the mandible based on cone-beam computed tomography (CBCT) scans. A retrospective cross-sectional and observational study was performed on 250 CBCTs from adults (18-69 years) with dentate jaws. Linear measurements of the MF, AL, and LF were evaluated to estimate the risk of injury to these structures during chin-related surgical procedures. The most frequent distance between the base of the mandible (BM) and MF was 8 mm (30.2%). In addition, 20.4% of the CTs had 6 mm from the vestibular cortical bone to the LF. The commonly found measurement from LF to the apex of the nearest tooth was 7 mm (24.0%); 64.2% of the CTs showed a 2-mm distance between the most distal point of the dental implant site to the most anterior point of the AL. Safety distances for genioplasty techniques (MF to mandible base > 6 mm, 96.6% [CI 95%, 95.0%-98.2%]) were observed. Considering the 5-mm cut-off point between the lower limit of a hypothetical bone graft and the chin, 65.4% (CI 95%, 58.9%-71.9%) of CTs were within this distance. Regarding the safety margin of 8 mm, 85.6% (CI 95%, 80.8%-90.4%) were up to this value. This study found safety margins for genioplasty and chin bone grafting surgical techniques that adopt a 5-mm cut-off point. Further similar studies assessing other surgical methods and employing larger samples from different geographical origins may contribute to this field of investigation.

Radiomorphometric indices for sex estimation in edentulous individuals: A receiver operating characteristic curve and discriminant function analysis-based study.

This study aimed to evaluate sexual dimorphism in Brazilian edentulous individuals using a formula based on mandible-related linear radiomorphometric measurements. A cross-sectional observational study was conducted with 390 panoramic radiographs (PRs) distributed into three age groups (51-60, 61-70, and 71-80 years). PRs were used to obtain linear measurements of the mandible and derived indices (superior and inferior panoramic mandibular indices [s-PMI and i-PMI, respectively], alveolar bone resorption [ABR] index), and the mandibular cortical index (MCI). Sex-related differences (and sex classifications) increased in the oldest cohort. Both s-PMI and i-PMI were shown to be significant in predicting sex in the age group from 71 to 80 years (p = 0.001 and p = 0.003, respectively) and, when considering the mean of the sides, only the s-PMI was significant (p = 0.037). The ABR index was significantly associated with sex (p = 0.004) and not influenced by MCI, and was used to construct a formula for sex estimation, which demonstrated 69.0% accuracy in the age group of 71-80 years. Sexual dimorphism was evidenced by the formula based on the s-PMI, i-PMI, and ABR indices.

Clinical, Imaging, and Therapeutic Aspects of Genial Tubercle Fractures: A Systematic Review.

PURPOSE: The present study reviewed the clinical, imaging, and therapeutic aspects of genial tubercle fracture (GTF). MATERIALS AND METHODS: A 2-phase systematic search of the literature was performed. Search strategies were developed for specific databases (PubMed, Scopus, Web of Science, Cochrane, and LILACS), including the gray literature (Open Grey and Google Scholar). The descriptors "genial tubercle," "fractures, bone," "mentalis," "spinae," and "mandible" were searched without restriction to year of publication. The CARE guideline was applied to evaluate methodologic aspects, and the Meta-Analysis of Assessment and Review Instrument was used to assess the risk of bias. The adopted level of significance was .05. RESULTS: Of 1,970 articles, 1,948 were excluded after applying the eligibility criteria. Furthermore, 2 studies were added through a manual search of the reference lists, totaling 24 articles. Occurrence of GTF was most common in women older than 61 years and men younger than 60 years (difference in age at occurrence was statistically significant; P = .019). The main clinical findings were edentulism, sublingual edema, and pain (P < .001). Previous trauma was commonly absent in women and present in men (P = .018). A cracking sound was mainly reported by women (P = .009). Isolated panoramic and occlusal radiographs were the most commonly performed examinations (P < .001). Diagnosis of sialolithiasis occurred in 37.5% of cases, and conservative treatment was performed in 76.6% of cases. CONCLUSION: GTF was mainly observed in older women, edentulous patients, and those without previous trauma. Conventional radiography and nonsurgical treatment were frequently reported.

Imaging Aspects of the Mandibular Incisive Canal: A PROSPERO-Registered Systematic Review and Meta-Analysis of Cone Beam Computed Tomography Studies

PURPOSE: This study aimed to perform a systematic review and meta-analysis of the literature on the mandibular incisive canal (MIC) studies using cone beam computed tomography (CBCT). MATERIALS AND METHODS: A PROSPERO-registered systematic review (#42017056619) was conducted following the PRISMA statements to summarize current knowledge on the CBCT aspects of the MIC. A search was performed in PubMed's Medline and Scopus databases, without date or language restrictions, using the algorithm {[(Interforaminal region) OR (mandibular incisive channel) OR (mandibular incisive nerve) OR (mental mandible) OR (anterior mandible) (cone beam computed tomography). Also, the references were crosschecked. The Meta-Analysis of Statistics Assessment and Review Instrument and meta-analysis was used to evaluate the selected studies. RESULTS: A total of 410 articles were found, and 25 studies were selected after a two-step selection process. The CBCT systems differed regarding field of view (FOV) (large, n = 3; medium, n = 2; small, n = 4; not informed, n = 16) and voxel size (0.15 to 0.4 mm). Geographically, the studies were distributed across four continents (South America, North America, Asia, and Europe), and there was a statistical significance of studies from the American and Asian continents (P < .0001). From 3,421 CBCT exams, the number of female patients was slightly higher than male, and the mean age ranged from 29.8 to 59.1 years. The overall mean prevalence of MIC was 89.6% ± 15.08%, and bilateral occurrence was statistically significant (P < .0001). The studies using a voxel size lower than 0.3 mm showed the highest mean prevalence (93.88%) in comparison with voxel size described as ≥ 0.3 mm (89.33%). Diameter (0.45 to 4.12 mm) and length (6.6 to 40.3 mm) showed great variability among the included studies. CONCLUSION: In summary, the results of this systematic review evidenced a high worldwide prevalence of MIC. There was no prevalence of MIC in relation to sex, and its presence was mainly related to adults between the fourth and sixth decades of life. In addition, great heterogeneity of methodologies was observed.