The effect of an early Le Fort III surgery on permanent molar eruption.
The purpose of this retrospective study was to evaluate the extent to which an early Le Fort III osteotomy affects the position and eruption of the permanent maxillary first and second molars. To test the null hypothesis that there are no changes in eruption patterns, 31 patients diagnosed with craniosynostoses (13 with Crouzon's syndrome, nine with Apert's syndrome, eight with Pfeiffer's syndrome, and one with Carpenter's syndrome) with a mean age at the time of surgery of 5.3 +/- 1.3 years were studied. All patients underwent a Le Fort III osteotomy performed by a single surgeon to correct the anatomical deformity for functional and psychosocial reasons. Eighteen patients with craniosynostoses who had not been operated on (11 with Crouzon's syndrome, four with Apert's syndrome, and three with Pfeiffer's syndrome) served as controls; they had a mean age of 21.2 +/- 9.5 years. First and second molar positions and eruption patterns were assessed separately on panoramic radiographs by three observers. For the patients who underwent surgery, long-term evaluation showed that although 79 percent of all first molars erupted compared with 100 percent for the control group (p < 0.001), only 18 percent of all second permanent molars erupted compared with 89 percent for the control group (p < 0.0001). The authors conclude that in a significant minority of cases, early Le Fort III osteotomy affects first molar eruption, whereas the probability of second molar eruption is significantly decreased in the majority of cases. Therefore, Le Fort III osteotomy sites should be positioned distal to the second molar tooth buds. If this is not possible, patients, parents, and dental professionals should be made aware of these early postosteotomy sequelae so that later treatment planning can be enhanced.