Sir, I read with interest the article 'Antibiotic prophylaxis and third molar surgery' (BDJ 2005, 198: 327) and agree completely with the authors opinion.

Nevertheless, there have been many controversial issues on dental extraction/minor oral surgery in irradiated jaws. One of which of course, is the use of antibiotic prophylaxis. In general, whenever we talk about patients with a history of radiotherapy, we usually refer to those who have direct radiation to the jawbones (normally for treatment oral cancer).

Hence that may explain why most maxillofacial surgeons will recommend prophylaxis use prior to extraction of lower posterior teeth (where the jawbone is dense)1. In my part of the world, besides oral cancer patients, we also see quite a large number of patients with a history of radiotherapy for the treatment of nasopharyngeal carcinoma (NPC), with effects to the oral cavity similar to that seen in oral cancer patients. Because of the difference in location of radiation, the recommendation for antibiotic use in this group of patients is different.

Thus, I would like to bring to your attention the protocol recommended by Tong et al.2 that is tailored specifically for NPC patients. This recommendation was formulated based on their experience with NPC patients in Hong Kong, where their study had shown that the risk of complicated wound healing and oral radio-necrosis after extraction could be explained by the radiation dose received by the bone and socket in which the teeth were situated. Extraction of teeth in areas outside the high radiation dose areas can be safely undertaken with antibiotic cover. Thus, they suggested that it would be safe to extract maxillary and mandibular anterior teeth if tooth extraction is considered absolutely necessary.

Tong et al.2 claimed that the extraction of premolars and mandibular molars is not associated with significant risk provided that an atraumatic technique and antibiotic cover are used. They think that antibiotic therapy is useful as an adjunctive treatment modality, thus it is a common practice to provide antibiotic cover for post-irradiation extractions. Among the antibiotics that could be prescribed is a single dose of either 3g oral amoxicillin or in those patients allergic to penicillin, 600 mg of oral clindamycin, one hour preoperatively.

Alternatively it has also been suggested that amoxycillin 250 mg or metronidazole 200 mg be given three times daily for 3-5 days of post-surgery to prevent infection in the healing phase. Problems arising from these extractions are manageable with relatively simple measures of wound debridement and closure and the need for careful follow-up until completed healing is necessary is emphasised.

Tong et al.2 suggested that when extraction of maxillary posterior teeth was necessary, prophylactic antibiotics are not sufficient to prevent the complication of delayed healing. They suggested that the protocol of Marx for giving hyperbaric oxygen (HBO) should be considered even though they did not agree with wholesale prescription of HBO therapy.

So, if we were to base our surgery on these recommendations, we can safely perform lower third molar surgery with a prophylaxis antibiotic cover but an extraction of upper molar teeth (or even minor oral surgery of the upper third molar) would not benefit from it. I personally have had bad experiences with upper third molar extractions (even auto-exfoliation) whereby prophylactic and/or therapeutic antibiotics have been of no advantage to the wound healing. As such, I advise my fellow colleagues to weigh carefully the need of prophylactic antibiotics in patients with a history of radiotherapy.