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.

PURPOSE: To systematically review the risk of permanent disability related to road traffic injuries (RTIs) and to determine the implications for future research regarding permanent impairment following road traffic crashes. METHODS: We conducted this systematic review according to the preferred reporting items for systematic reviews and meta-analysis statement. An extended search of the literature was carried out in 4 major electronic databases for scientific research papers published from January 1980 to February 2020. Two teams include 2 reviewers each, screened independently the titles/abstracts, and after that, reviewed the full text of the included studies. The quality of the studies was assessed using the strengthening the reporting of observational studies in epidemiology (STROBE) checklist. A third reviewer was assessed any discrepancy and all data of included studies were extracted. Finally, the data were systematically analyzed, and the related data were interpreted. RESULTS: Five out of 16 studies were evaluated as high-quality according to the STROBE checklist. Fifteen studies ranked the initial injuries according to the abbreviated injury scale 2005. Five studies reported the total risk of permanent medical impairment following RTIs which varied from 2% to 23% for car occupants and 2.8% to 46% for cyclists. Seven studies reported the risk of permanent medical impairment of the different body regions. Eleven studies stated the most common body region to develop permanent impairment, of which 6 studies demonstrated that injuries of the cervical spine and neck were at the highest risk of becoming permanent injured. CONCLUSION The finding of this review revealed the necessity of providing a globally validated method to evaluate permanent medical impairment following RTIs across the world. This would facilitate decision-making about traffic injuries and efficient management to reduce the financial and psychological burdens for individuals and communities.
Humans ; Accidents, Traffic ; Disabled Persons ; Abbreviated Injury Scale ; Databases, Factual ; Wounds and Injuries/etiology*