Statements of the problem: The presence of a tooth in a mandibular angle fracture is a common dilemma, with as many as 85% of angle fractures containing a third molar. Prophylactic tooth extraction was routinely employed to avoid serious complications, such as osteomyelitis and nonunion. However, antibiotic administration has allowed for retention of teeth, leaving the option of extraction for more dire circumstances. Nonetheless, there is no clear consensus on evidence-based criteria for extraction or management of asymptomatic third molar during open reduction and internal fixation (ORIF).
Materials and Methods: A protocol was designed and implemented for a systematic review, integrating evidence from primary studies and systematic reviews to test the null hypothesis of no difference in patient outcomes following retention versus removal of teeth in line of mandibular angle fractures.The PubMed, EMBASE, the Cochrane Library, Elsevier text mining tool and clinicaltrials.gov trial registries were queried through March 2018 for all evidence on traumatic mandibular fractures. Quality of evidence was determined based on Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology.
Method of data analysis: Meta-analyses were performed when definitions of active and control interventions and patient outcomes were deemed similar. We examined consistency in results across studies with chi-square tests and I2 statistics with a threshold for significant heterogeneity of I2 >50%. STATA software was used to calculate treatment effect estimates. Statistical significance was evaluated at a 95% confidence level.
Results: Overall, 1212 studies were screened for inclusion, and 27 studies met the inclusion criteria, including a randomized control trial (RCT), two systematic reviews, and 23 case series. According to one systematic review, extraction of asymptomatic teeth was associated with high risk of inferior alveolar nerve (IAN) injury. The most common individual complications included infection, malocclusion, and wound dehiscence. While the quality of evidence was low, significant differences in overall complications in favor of tooth retention were identified (OR 0.54, 95% CI 0.37-0.79). Furthermore, specific indications for tooth removal varied across the studies.
Outcomes data: As mentioned, there were 23 primary studies that investigated outcomes following tooth extraction or retention following ORIF of mandibular angle fractures. The overall complication rate was lower in retention of teeth in the line of angle fractures (OR 0.54, 95% CI 0.37-0.79). Similarly, tooth retention was favorable with respect to major complications (OR 0.47, CI 0.24, 0.92) and malocclusion (OR 0.56, CI 0.32-0.97). Overall, the GRADE quality of evidence was low for the aforementioned outcomes, and very low for the risk of IAN injury, which favored tooth retention.
Conclusion: This is the largest and most extensive meta-analysis on this subject to date and first to explore intervention on all reported outcomes and complications. While the GRADE quality of evidence is low, there is an association between extraction of teeth in the line of angle fractures and increased risk of developing complications. The AO foundation has defined indications for extraction, including the presence of infection or dental pathology or interference with obtaining adequate reduction. However, there is still extremely limited evidence regarding extraction of teeth in the line of angle fractures and high quality RCTs are needed to further specify indications for extraction.
1. Chuong R, Donoff RB, Guralnick WC. A retrospective analysis of 327 mandibular fractures. Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. May 1983;41(5):305-309.
2. Ellis E, 3rd. Open reduction and internal fixation of combined angle and body/symphysis fractures of the mandible: how much fixation is enough? Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. Apr 2013;71(4):726-733.