What Are Possible Contributors to Associated Dental Injury in Mandibular Fractures?

PURPOSE: Among previous reports on dental injuries associated with mandibular fractures, there are few investigating the conditions under which dental injuries commonly occur. The aim of this study was to determine specific characteristics of mandibular fractures accompanied by dental injuries. METHODS: This retrospective cohort study included dentate patients with mandibular fractures treated at a tertiary trauma center between 2011 and 2019. The data were analyzed according to 2 outcome variables: patients with additional dental injuries and patients without. The predictor variables were patient age, sex, accident mechanism, number and location of mandibular fractures, and presence of submental lacerations. Odds ratios for the risk factors for dental injury were calculated in conjunction with descriptive statistics. Binary logistic regression analysis was also performed to identify the factors associated with dental injuries as dependent variables. RESULTS: Of 252 patients who had only mandibular fractures, 95 (37.7%) had associated dental injuries. In the group with dental injuries, 55.8% of mandibular fractures were caused by a fall (P = .003). Condyle fractures (77.9%) with dislocation (67.6%) and bilateral involvement (41.9%) were more common than in the group without dental injuries (P < .001). In patients with dental injuries, the incidence of 3 or more fractures (29.5%) was significantly higher than in the group without dental injuries. Dental injuries were more likely to occur in patients with concomitant submental lacerations (confidence interval (CI) 1.135-4.983, P = .02), and the risk of dental injury was significantly lower in the presence of angle fractures (CI 0.113-0.999, P = .045). CONCLUSIONS: A frontal impact involving the anterior part of the mandible is often associated with condyle and multiple mandibular fractures. This seems to be the typical mechanism for concomitant dental injuries. Submental laceration can be considered a prime sign of associated dental injuries.