Prevalence of bacteraemia following third molar surgery.

OBJECTIVE

To investigate the prevalence and aetiology of bacteraemia following third molar extractions (B-TME), analysing the factors affecting its development.

METHODS

The study group was formed of 100 patients undergoing third molar extractions under general anaesthesia. Peripheral venous blood samples were collected at baseline, 30 s after a mandibular third molar extraction and 15 min after completing the final extraction. Samples were inoculated into BACTEC aerobic and anaerobic blood culture bottles and were processed in the BacT/Alert. Subculture and further identification of the bacteria isolated was performed using conventional microbiological techniques.

RESULTS

The prevalence of bacteraemia following third molar surgery was 62% at 30 s after the first dental extraction and 67% at 15 min after finishing the final extraction. The bacteria most frequently identified in the positive blood cultures were Streptococcus viridans (87.9%).

CONCLUSION

In our series, the prevalence of B-TME at 30 s after a single third molar extraction was high, principally being of streptococcal aetiology, and was independent of the oral health status and the magnitude of the surgical procedure. Positive blood cultures persisted for at least 15 min after three to four dental extractions in a higher number of patients, questioning the supposedly transient nature of bacteraemia following dental extractions.