Do Postoperative Antibiotics Decrease the Frequency of Inflammatory Complications Following Third Molar Removal?

Purpose: 

The role of antibiotics in third molar (M3) operations is controversial.  The purpose of this study was to answer the question: Among patients whose M3s are removed in private OMS practices, do those patients who receive only postoperative antibiotics, when compared to patients who receive no antibiotics, have a lower frequency of postoperative inflammatory complications?

Materials and Methods: 

Study Design:  A prospective cohort study was designed and subjects were enrolled derived from the population of patients who had at least one M3 removed in an ambulatory private practice setting in the US between June, 2011 and May, 2012 by clinicians participating in a practice-based research collaborative (PbRC).^[1]

Study Variables:  The predictor variable was postoperative antibiotic use categorized as postoperative antibiotics alone or no antibiotics.  The primary outcome variable was the presence or absence of a postoperative inflammatory complication following M3 removal.  Postoperative inflammatory conditions assessed were alveolar osteitis (AO) or surgical site infection (SSI). AO was diagnosed based on history and clinical exam with new onset or increasing pain greater than 36 hours after the operation with clinical exam demonstrating loss of the blood clot with exposed bone, irrigation or gentle probing of the site reproducing the pain, and pain relief upon application of an anodyne dressing.  SSIs were diagnosed by frank purulence of the extraction site at any point postoperatively or unanticipated edema or pain warranting operative intervention or further antibiotic administration.  Other study variables were grouped into categories:  demographic (sex and age), risk factors (ASA, BMI, alcohol or tobacco use, medications and chronic conditions), M3 specific factors (number of M3s removed, preoperative disease score and operative difficulty score), and treatment (intraoperative complications and chlorhexidine use). 

Methods of Data Analysis:  Descriptive, bivariate, and multiple logistic regression statistics were calculated to measure the association between isolated postoperative antibiotic use and postoperative inflammatory complications (AO/SSI) following M3 removal with statistical significance set at ≤0.05.

Results/Outcomes Data:

The sample was composed of 1,877 patients having 5,631 M3s extracted of which 61% received postoperative antibiotics only.  The overall inflammatory complication (AO/SSI) frequencies in the postoperative antibiotic only group versus no antibiotic group were 4.3% and 7.5%, respectively (p=0.003).  The frequency of AO in the postoperative antibiotic and non-antibiotic groups were 4.0% and 6.3% respectively (p=0.03).  The frequency of SSIs in the postoperative antibiotic and non-antibiotic groups were 0.4% and 1.4% respectively (p=0.03). After adjusting for age, sex, and operative difficulty, postoperative antibiotic use when compared to no antibiotic use was associated with a 50% decreased risk for postoperative inflammatory complications (odds ratio = 0.49, 95% confidence interval=(0.32-0.73), p<0.001).

Conclusions:  The results of this study suggest that postoperative antibiotic therapy when compared to no antibiotic use is associated with a decreased risk of postoperative inflammatory complications (AO/SSI) following third molar removal.  These findings are consistent with a 2013 Cochrane review indicating the use of antibiotics decreased the risk of AO and SSI following extraction of M3s.^[2]

References:  

1. Dodson TB, Gonzalez ML, American Association of Oral and Maxillofacial Surgeons Anesthesia and Third Molar Extraction Benchmark Study: Rationale, methods, and initial findings, Journal of Oral and Maxillofacial Surgery (2016), doi: 10.1016/j.joms.2015.11.032
2. Lodi G, Figini L, Sardella A, Carrassi A, Del Fabbro M, Furness S.  Antibiotics to prevent complications following tooth extractions (Review).  Cochrane Database Syst Rev.  2013. 

Disclosure:  This study was supported in part by the AAOMS Anesthesia and Third Molar Extraction Outcome Studies (PI – T.B. Dodson) and the University of Washington Department of OMS Research and Education Fund.