Effectiveness of antibiotic prophylaxis in third molar surgery: a meta-analysis of randomized controlled clinical trials.

Purpose: We conducted a synthetic quantitative review of the published clinical trials on the effectiveness of antibiotic prophylaxis in third molar surgery.
Materials and Methods: Electronic databases were searched for randomized controlled trials. The primary outcome variables included alveolar osteitis (AO) and surgical wound infection. The extracted data were analyzed using a meta-analytical program with a random-effect model. Number needed to treat (NnT) was calculated.
Results: A total of 2,932 patients randomized in 16 clinical trials reported AO as an outcome. AO occurred in 84 of 1,350 patients in the treatment group, a frequency of 6.2%; and in 228 of 1,582 patients in the control group, a frequency of 14.4%. Systemic antibiotic therapy was effective in reducing the risk of AO (odds ratio [OR], 2.175) with an NnT of 13. A total of 2,396 patients randomized in 12 clinical trials reported wound infection as an outcome. Wound infection occurred in 44 of 1,110 patients in the treatment group, a frequency of 4%; and in 78 of 1,286 patients in the control group, a frequency of 6.1%. Systemic antibiotic therapy was effective in reducing the risk of wound infection (OR, 1.794) with an NnT of 25. Antibiotics reduced the risk of AO and wound infection only when first dose was given before surgery.
Conclusions: Systemic antibiotics given before the surgery were effective in reducing the frequencies of AO and wound infection after third molar surgery.