title: Effect of presurgical incisor extrusion on stability of anterior open bite malocclusion treated with orthognathic surgery.
abstract: The records of 40 nongrowing open bite patients treated with orthodontics and maxillary surgery were divided into two groups and evaluated. The extrusion group (n = 19) included those patients who had presurgical maxillary incisor extrusion of at least 1.5 mm. In the nonextrusion group (n = 21), the maxillary incisors were maintained or intruded prior to surgery. Statistical analysis showed no relationship between presurgical extrusion of the maxillary incisors and the stability of open bite correction; the maxillary incisors were generally stable long term in both groups. Overbite decreased a mean of -0.97 mm in the extrusion group and -0.67 mm in the nonextrusion group during the mean 5-year 10-month follow-up period after appliance removal. Twenty-five percent (10 of 40, 5 from each group) of the sample had no incisal overlap long term. These findings suggest that a moderate amount of presurgical incisor extrusion or lack of extrusion are stable long term and have little influence on posttreatment stability of open bites. The decrease in overbite observed after treatment may result from the influence of various dental, skeletal, and soft tissue factors rather than from any single factor.
authors.affiliation: Department of Orthodontics, University of Washington, Seattle, USA.
authors.forename: F M
authors.initials: FM
authors.lastname: Lo
authors.forename: P A
authors.initials: PA
authors.lastname: Shapiro
mesh_terms: D000328:Adult; D002508:Cephalometry; D005260:Female; D006801:Humans; D007180:Incisor; D008297:Male; D008310:Malocclusion / Q000175:diagnosis / Q000601:surgery*; D008437:Maxilla; D009971:Orthodontics, Corrective / Q000379:methods; D019340:Osteotomy, Le Fort; D011300:Preoperative Care; D012008:Recurrence; D012044:Regression Analysis; D014087:Tooth Movement Techniques / Q000379:methods*