Prevalence and risk factors of early and delayed postoperative infections after lower third molar surgery: a meta-analysis

Abstract

Aim: To determine the prevalence and possible risk factors associated with early and delayed postoperative infections after lower third molar surgery, a meta-analysis of clinical studies was performed. Materials and Methods: A systematic electronic and hand search was performed and 14 articles were finally included. Sample size, number of lower third molars extracted, infection criteria, number of infections and follow-up period were evaluated from each study reviewed. Meta-analysis was performed by the pooled prevalence of early and delayed postoperative infections and by the pooled odds ratio (OR) of risk factors. Eight randomized controlled trials, 2 case control studies, 3 cohort studies and 1 non-randomised controlled trial were included for data extraction. Results: The pooled estimated prevalence of early infection was 2.05 % with a standard error of 397,2. Pell & Gregory category C was not significantly associated to infection, having an OR=1.66 (95 % CI: 0.81 to 3.41). Vertical third molar’s position was not significantly associated with infection with an OR= 0.910 (95% CI: 0.411 to 2.01). The use of antibiotics either as a prophylaxis before or immediately after extraction, did not significantly reduce the infection risk with an OR= 0.91 (95% IC: 0.41 to 2.01). However, having a pooled OR=2.52 (95% CI: 1.22 to 5.21) class III in the classification of Pell & Gregory seemed to be the only risk factor statistically significant for developing early infections. Delayed infections’ data could not be statistically analyzed in present meta-analysis. Conclusion: Prevalence of early infection is estimated at 2.05%, so it is low compared with other postoperative complications. The only risk factor that seems to be statistically associated with postoperative infections is class III of Pell & Gregory classification.