Infection Rate After Wisdom Tooth Extraction Without Antibiotics
Without antibiotic prophylaxis, the infection rate after third molar (wisdom tooth) extraction in healthy patients ranges from approximately 3-10%, with the most robust evidence showing rates of 3.5-8.5%. 1, 2, 3
Evidence-Based Infection Rates
Primary Data from High-Quality Studies
A 2012 Cochrane systematic review of 1,523 patients undergoing third molar extraction found that antibiotics reduce infection risk by 70% (RR 0.29,95% CI 0.16-0.50), which mathematically indicates a baseline infection rate of approximately 8-10% without antibiotics. 1
A 2021 Japanese prospective study of 5,106 mandibular wisdom tooth extractions reported an overall surgical site infection (SSI) rate of 3.5% across all patients, including those who received antibiotics. 2
A 1994 randomized controlled trial comparing open versus semi-closed wound healing after lower third molar removal found infection rates of less than 1% with open wound healing and 6% with semi-closed techniques, demonstrating that surgical technique significantly impacts infection rates independent of antibiotic use. 3
Key Clinical Context
The number needed to treat (NNT) with antibiotics to prevent one infection is 12 healthy patients (range 10-17), meaning that without antibiotics, approximately 8-10% of patients would develop infection. 1
Dry socket (alveolar osteitis) occurs in approximately 5-8% of cases without antibiotics, as antibiotics reduce this risk by 38% (RR 0.62,95% CI 0.41-0.95), requiring treatment of 38 patients to prevent one case. 1
Factors That Modify Infection Risk
Surgical Technique Impact
Open wound healing technique reduces infection rates to less than 1%, while semi-closed wound healing increases infection rates to 6%, demonstrating that surgical approach is more important than antibiotic prophylaxis in preventing infection. 3
Poor oral hygiene significantly increases postoperative infection rates, particularly with semi-closed wound healing, but has less impact when open wound healing is used. 3
Patient Population Considerations
All high-quality evidence comes from healthy patients undergoing impacted third molar extraction, typically performed by oral surgeons—there is no evidence for infection rates in patients with severe dental caries, periodontal disease, or immunocompromise. 1
Patients at higher risk of infection (immunocompromised, concomitant illnesses) are likely to have higher baseline infection rates and more severe complications, though specific rates are not established in the literature. 1
Clinical Implications
Risk-Benefit Analysis
For every 21 patients (range 8-200) who receive prophylactic antibiotics, one will experience a mild and transient adverse effect (RR 1.98,95% CI 1.10-3.59). 1
The decision to use antibiotics must balance the 8-10% baseline infection risk against antibiotic resistance concerns and adverse effects, particularly given that most infections in healthy patients are mild and treatable. 1
When Infection Rates Are Lower
Preoperative antibiotic administration (versus postoperative) reduces infection odds by 63% (OR 0.37,95% CI 0.22-0.63), suggesting that timing of prophylaxis significantly impacts outcomes. 2
Amoxicillin demonstrates lower infection rates compared to third-generation cephalosporins (OR 0.76,95% CI 0.55-1.04), though this did not reach statistical significance. 2
Important Caveats
The 3-10% infection rate applies specifically to healthy patients undergoing surgical extraction of impacted wisdom teeth—rates may be substantially higher in patients with active infection, poor oral hygiene, or immunocompromise. 1, 3
Surgical technique, wound management approach, and oral hygiene status appear to be more important determinants of infection risk than antibiotic prophylaxis alone. 3
The evidence does not address infection rates in general dental practice settings where extractions are performed for severe caries or periodontal infection, which may have different baseline risks. 1