Pre-operative chlorhexidine mouth rinses reduce the incidence of dry socket

Medline and the Cochrane library databases were searched and additional studies located by scrutinising publications obtained.

Studies included in analysis were randomised controlled trails (RCT) about prevention of alveolar osteitis (AO) that were written in English, French, German or any of the Nordic languages (Danish, Finnish, Icelandic, Norwegian, Swedish). Duplicate publications, those with flawed data and RCT that generally addressed postoperative complications were excluded.

The RCT were quality assessed using the Jadad scale and then categorised and tabulated, according to the main test interventions, to the following domains: antibiotics trials; chlorhexidine trials; trials of PEPH (an antifibrinolytic-active propylic ester of p-hydrobenzoic acid); and other trials including factorial trials (combined interventions) and factorial test groups of RCT belonging to any of the aforementioned domains.

A total of 90 publications were identified, from which 32 RCT were included, from 12 different countries, covering the time period 1971-2005. An adequate method of random allocation was reported in 47% of the RCT. Eight different RCT assessed different antibiotic regimens. Tetracycline trials revealed the greatest preventive effects on AO, with absolute risk reductions (ARR) ranging from 12-31% and numbers needed to treat (NNT) ranging from three to eight treated individuals. The effect of chlorhexidine rinses for prevention of AO was studied in five RCT with ARR ranging from 3-25% (NNT, four to 36 treatments). Overall, evidence about chlorhexidine rinses on the prevention of AO was inconclusive, but the available data indicate that 0.12% chlorhexidine rinsing pre-operatively and 7 days postoperatively reduces the frequency of AO following surgical removal of lower third molars. Similarly, evidence for the effectiveness of the antifibrinolytic agent PEPH (considered in three trials) was inconclusive, as was that for the other 18 trials agents.

Local treatment with tetracycline, and also 0.12% chlorhexidine rinsing pre-operatively and 7 days postoperatively, seem to have significant and clinically relevant preventive effect on AO following surgical removal of lower third molars.