Long-term profile changes associated with successfully treated extraction and nonextraction Class II Division 1 malocclusions.
This study was undertaken to compare the post-treatment and long-term soft tissue profiles of successfully managed and stable Class II, division 1 malocclusions treated with either 4 first premolar extractions or nonextraction therapy. It was hypothesized that, if sound extraction decisions were made according to accepted treatment objectives and successful treatment outcomes were achieved, there should be no differences between groups in soft tissue profiles post-treatment and long-term post-retention. The sample consisted of 63 Caucasian adolescents (23 extraction, 40 nonextraction). Correction of the malocclusion was achieved using a combination of cervical headgear concurrent with mandibular growth and maxillary incisor retraction. Pretreatment, post-treatment, and long-term post-retention lateral cephalometric radiographs were evaluated. The soft tissue facial profiles of the extraction and nonextraction samples were the same following active treatment and long-term post-retention. Progressive flattening of the facial profile was observed in both samples. This flattening was attributed to the maturational changes associated with continued mandibular growth and nasal development and was not influenced by whether or not teeth were removed. Long-term lip positions were more retrusive than the ideals suggested by Ricketts and Steiner, but close to the values reported for normal, untreated adults of similar ages. The pretreatment position and thickness of the lower lip as well as the initial maxillomandibular skeletal relationship may be predictors of post-treatment or long-term lower lip position.
Department of Orthodontics, University of Washington, Seattle, USA. ezierhut@aol.com
E C
EC
Zierhut
D R
DR
Joondeph
J
J
Artun
R M
RM
Little
D000293:Adolescent; D000328:Adult; D002508:Cephalometry; D002648:Child; D005145:Face / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D009971:Orthodontics, Corrective / Q000379:methods*; D012008:Recurrence; D012044:Regression Analysis; D018709:Statistics, Nonparametric; D014081:Tooth Extraction; D016896:Treatment Outcome