The role of multiple segment osteotomies in orthognathic surgery.

Multiple segment orthognathic (MSO) surgery is an effective approach to deal with a wide range of dento-facial deformities that have occlusal problems. The indications for MSO surgery were patients with dentofacial deformities and malocclusion requiring stable correction within a short overall treatment period. From 1991 to 1998, 107 patients had MSO orthognathic procedures done at Chang Gung Memorial Hospital for maxillary protrusion/deformity (34 cases), maxillary protrusion and mandibular prognathism (69 cases), and non-cleft maxillary retrusion (4 cases). Follow up period ranged from 6 months to 7 years and results showed stability in movements with only 3 complications. The average overall treatment time was approximately 15 months. Our experience with 107 consecutive patients have shown the results of MSO surgery to be good and the procedure safe with no tooth or segment loss.

Combining single- and double-tooth osteotomies with traditional orthognathic surgery.

Combining large-segment orthognathic surgery and unitooth or small-segment surgery is an effective approach to deal with a wide range of dentofacial deformities that have minor to severe occlusal problems. The indications for combining single- or double-tooth osteotomies with traditional orthognathic surgery were patients with dentofacial deformities and malocclusion requiring stable correction within a short overall treatment period. From 1991 to 1998, a total of 36 patients underwent combination single- or double-tooth-segment osteotomy with traditional orthognathic procedures performed at Chang Gung Memorial Hospital. The indications for surgery were maxillary protrusion (N = 5), bimaxillary protrusion (N = 19), mandibular prognathism with maxillary protrusion (N = 11), and noncleft maxillary retrusion (N = 1). The types of osteotomies performed were the Le Fort I, the anterior segmental osteotomies of the maxilla or the mandible, the palatal split, and the posterior segment in combination with single-tooth or double-tooth segments. Follow-up ranged from 12 months to 6 years and showed stability in the movements with no complications. There was no loss of any "osteotomized" segment. The average overall treatment time was approximately 18 months--5 months preoperative and 13 months postoperative orthodontic treatment. This was at least 6 months shorter in duration compared with traditional orthognathic surgery. Combining traditional orthognathic surgery with single- or double-tooth segments allows us to treat complex dentofacial deformities in the vertical, transverse, and sagittal dimensions with differential repositioning of all segments, either major or minor, simultaneously. The authors' experience with 36 consecutive patients evidence good results and demonstrate the procedure to be safe with minimal complications.

Localized periodontitis induced by rubber bands. Report of two cases.

Two cases of severe localized periodontal destruction caused by rubber bands migrating toward the apices subgingivally are reported. In both cases the patients received periodontal treatment followed by orthodontic treatment and the affected teeth were maintained for two years without extraction. The inappropriate use of rubber bands may cause severe periodontal destruction or even lead to tooth mortality. The use of retentive hooks on orthodontic bands and twisted wire ligatures, as well as close professional supervision, are highly recommended to avoid this hazardous situation.