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Too little too late

Sir, since the classic works of Burke, Polk and Lopez-Mayor in the 1960s, peri-operative administration of antibiotics is a proven and accepted clinical method to reduce post-operative infections in various surgical procedures, named 'antibiotic prophylaxis'.1 Drs Kitchen (BDJ 2004; 196: 515 and BDJ 2006; 200: 363) and Williams (BDJ 2006; 200: 124) recommended a single at- or post- extraction dose of 200mg metronidazole for prevention of 'infected socket'. According to their experience in the last few years, oral administration of 200mg metronidazole 'has stopped all incidences of post-operative infection' or made them 'a rarity' and 'the cost ... is negligible'. They stated that the common practice of a multi-dose post-operative course is unnecessary, but a single-dose is preferred. However, in my opinion their recommendation is wrong and based on a misconception.

Firstly, an at- or post-operative administration of antibiotics violates the basic principle of prophylaxis as the antimicrobial agent must be within the tissue from the beginning of the operation in adequate level, waiting for the bacterial invasion,1 whereas oral administration of 200mg metronidazole produces a plasma concentration of 4μm/ml after one hour, a half of the mean effective concentration of this antimicrobial agent.2 Too little and too late.

Secondly, although it is a widespread practice,3,4 the peri-operative use of antibiotic agents in third molar surgery has not been shown to reduce post-operative complications in healthy patients.5 While the prophylactic use of antibiotics in bleeding dental procedures in cardiac and orthopaedic compromised patients are recommended by official institutions and considered as a standard of care, the routine use of antibiotics following third molar surgery in healthy patients is firmly contraindicated by the literature as costly, harmful, and having little or no effect.6 Recently, Augmentin has been reported to reduce post-third molar surgery complications,7 but there has been no recommendation of routinely prescribed Augmentin after tooth extraction.

Ritzau et al.8 and Bergdahl and Hedstrom9 showed that pre-operative single administration of 1000mg or 1600mg metronidazole did not achieve a significant reduction of post-extraction complications compared to placebo. I am doubtful whether an at- or post-operative administration of 200mg metronidazole is more effective than a pre-operative 1000/1600mg dose.

The recently gained acceptance of the concept of evidence-based dentistry is aimed to base dental practice on profound foundations of research rather than personal experiences, feelings and believes. According to the current literature, if the authors want to 'reduce the quantity of antibiotics dispensed', as stated, they should not give oral antibiotics at all.


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Zadik, Y. Too little too late. Br Dent J 201, 2–3 (2006).

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