Effect of lavage on the incidence of localized osteitis in mandibular third molar extraction sites

Four hundred twenty-two mandibular third molars were extracted in 211 patients. After extraction, one half of the surgical sites were subjected to a 175 ml. lavage with normal saline solution, and the other half received a lavage of less than 25 ml. of normal saline solution. Comparisons revealed the following: 1. The overall incidence of localized osteitis was 8.3 per cent (thirty-five of 422 sites). 2. Localized osteitis occurred at twelve of 211 (5.7 per cent) sites which were subjected to the higher-volume lavage. 3. Localized osteitis occurred at twenty-three of 211 (10.9 per cent) sites which were subjected to minimal lavage. 4. The incidence of localized osteitis was determined in the various age groups as follows: ages 15 to 20, 5.0 per cent; ages 21 to 35, 10.4 per cent; ages 26 to 30, 14.7 per cent. 5. Localized osteitis occurred at eight of 175 (4.5 per cent) partial-impaction sites, whereas it occurred at twenty-seven of 246 (11 per cent) complete-impaction sites. 6. The incidence of localized osteitis at extraction sites in female patients taking oral contraceptives was 19.4 per cent (seven of thirty-six sites). 7. Postoperative infection occurred at seven of 422 extraction sites (1.4 per cent); six of these occurred at sites which were subjected to minimal lavage. These results indicate that the use of a 175 ml. lavage with normal saline solution after extraction of mandibular third molars will significantly reduce the incidence of localized osteitis to approximately one half of that observed when only a minimal-volume lavage is used. The results also suggest that age, type of impaction, and whether the patient is taking oral contraceptives are all important factors to be considered in the incidence of localized osteitis.