(54) Does the Level of Impaction Affect the Management of Third Molars in the Treatment of Mandibular Angle Fractures?

Abstract: Studies have shown that approximately 70% of mandibular angle fractures are associated with a third molar.[1] Conventional teaching recommends retaining the teeth associated with mandible fractures during open reduction and internal fixation, except in scenarios where teeth are displaced, fractured, infected, have associated pathology, or impede the ability to reduce fractures.[2, 3] However, there is limited investigation into the level of impaction of teeth in the line of the fracture and how this may impact management. We hypothesize that retention of erupted third molar teeth would be associated with increased incidence of post-operative infection for angle fractures treated in an open fashion, and that extraction of these teeth at the time of fracture repair to allow for primary closure would reduce the risk of post-operative infection. A retrospective chart review was conducted of a total of 151 mandibular angle fractures treated at Cook County Health by the Division of Oral & Maxillofacial Surgery from 2018 through 2022. Sixty-eight fractures met the inclusion criteria, including adequate follow-up and the presence of a third molar tooth in the line of a non-infected angle fracture. Documented clinical outcome measures were collected including clinical signs and symptoms of infection, post-operative antibiotic use, and need for hardware removal. Outcomes were analyzed in relation to level of impaction and management of associated teeth using a chi-squared test. Out of 68 fractures, there were 39 erupted or partially erupted and 29 impacted associated teeth. Erupted teeth were extracted 87.2% of the time and impacted teeth were extracted 82.8% of the time. Average follow-up was 26.9 weeks. The overall infection rate was 22.1%. For all fractures, infection rates were not affected by management of associated teeth (retained vs extracted, 20.0% vs 22.4%, p = 0.865). However, fractures associated with impacted teeth had a lower infection rate overall compared to erupted teeth to a statistically significant degree (6.9% vs 33.3%, p = 0.009). Extraction of erupted teeth did result in a lower infection rate compared to retention of these teeth (32.4% vs 40.0%, p = 0.735) and impacted teeth that were extracted had a higher infection rate compared to those that were not (8.3% vs 0.0%, p = 0.504), but these findings were not statistically significant. Our study was limited due to the small sample size of fractures meeting the inclusion criteria and may be confounded by patient comorbidities and variability in post-operative compliance. Overall, level of impaction does appear to influence infection rates and fractures associated with teeth exposed to the oral cavity carry higher rates of post-operative infections, however, extraction of these teeth at the time of repair may not mitigate this increased risk.

References

1. Ellis, Edward, et al. “Ten Years of Mandibular Fractures: An Analysis of 2,137 Cases.” Oral Surgery, Oral Medicine, Oral Pathology, vol. 59, no. 2, 1985, pp. 120–129., https://doi.org/10.1016/0030-4220(85)90002-7.

2. Kahnberg, K.-E., and A. Ridell. “Prognosis of Teeth Involved in the Line-of Mandibular Fractures.” International Journal of Oral Surgery, vol. 8, no. 3, 1979, pp. 163–172., https://doi.org/10.1016/s0300-9785(79)80015-0.

3. Miloro, Michael, et al. “Contemporary Management of Mandibular Fractures.” Peterson's Principles of Oral and Maxillofacial Surgery, People's Medical Publishing House, 2011, pp. 420–421.