Risk factors for post-extraction infection of mandibular third molar: A retrospective clinical study

Post-extraction infection is one of the most concerning complications of mandibular third molar extraction, which is the most common procedure in oral and maxillofacial surgery. We investigated risk factors for post-extraction infection by retrospectively analyzing 2,513 teeth/cases of mandibular third molar extraction (1,040 males, 1,473 females) performed at a single medical facility in Kobe, Japan from January 2014 to May 2022. The predictive variables were categorized as patient attributes, health status, and anatomic, pathological, and operative variables that may be associated with post-extraction infection. The outcome variable was the post-extraction infection rate. The post-extraction infection rate was 5.73 % (144 of the 2,513 teeth), and the mean age of the patients with a post-extraction infection was 41.76 ± 16.8 years. Our analyses also revealed that the postoperative infection rate was significantly increased in patients aged ≥36 years. A multivariate logistic regression analysis showed that the following variables were significantly associated with post-extraction infection: preoperative antibiotic administration (odds ratio [OR] 4.68, p < 0.001), postoperative paresthesia of the inferior alveolar nerve (OR 4.34, p < 0.001), intraoperative hemostatic procedure (OR 1. 74, p = 0.008), position of Pell and Gregory classifications (OR 1. 70, p < 0.001), Winter's classification (OR 1.28, p < 0.03), and age (OR 1.03, p < 0.001). Oral and maxillofacial surgeons should be aware of these risk factors.