Marginal bone level after Le Fort I osteotomy.

The object of the study was to assess the effect of Le Fort I osteotomy and maxillary interdental osteotomy on the marginal bone level. Forty patients (25 female, 15 male, mean age 24 years, range 15-46) treated for dentofacial deformities comprised the subjects of the study and underwent Le Fort I osteotomy with or without simultaneous interdental osteotomy. Outcome was measured by marginal bone level measured in radiographs before and 1 year after operation. All patients had good oral hygiene. There was an overall significant mean marginal bone loss of 0.2 mm at surfaces without interdental osteotomy (P = 0.001). When the bone loss of the different types of teeth was considered separately, only those of central incisors (0.5 mm, P = 0.0001) and canines (0.4 mm, P = 0.004) were significant. Interdental osteotomy caused an overall mean marginal bone loss of 0.4 mm, but this was not significantly different from that of teeth without interdental osteotomy (P = 0.07). When the bone loss of different types of teeth after interdental osteotomy was considered separately, the only difference that achieved significance was that of premolars (0.3 mm, P = 0.04). Though there were significant differences, none of them was large enough to have any clinical relevance. Le Fort I osteotomy and interdental osteotomy may only in a few instances cause marginal bone loss of clinical relevance. However, the present study was performed on patients with good oral hygiene. The above conclusions may therefore not be valid for patients who, prior to surgery, already have a compromised marginal bone level.