Zierhut E C, Joondeph D R, Artun J, Little R M
Department of Orthodontics, University of Washington, Seattle, USA.
Angle Orthod. 2000 Jun;70(3):208-19. doi: 10.1043/0003-3219(2000)070<0208:LTPCAW>2.0.CO;2.
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.
本研究旨在比较采用拔除4颗第一前磨牙或不拔牙矫治成功且稳定的安氏II类1分类错牙合畸形患者治疗后及长期的软组织侧貌。研究假设为，如果根据公认的治疗目标做出合理的拔牙决策并取得成功的治疗效果，那么两组患者治疗后及长期保持后的软组织侧貌应无差异。样本包括63名白种青少年（23名拔牙患者，40名不拔牙患者）。采用颈带矫治器配合下颌生长及上颌切牙后移的方法矫正错牙合畸形。对治疗前、治疗后及长期保持后的头颅侧位片进行评估。拔牙组和不拔牙组患者在积极治疗后及长期保持后的软组织面部侧貌相同。两组患者均出现面部侧貌逐渐变平的情况。这种变平归因于与下颌持续生长和鼻部发育相关的成熟变化，且不受是否拔牙的影响。长期的唇部位置比里氏（Ricketts）和施泰纳（Steiner）提出的理想值更后缩，但接近报道的同龄正常未治疗成年人的值。下唇的治疗前位置和厚度以及最初的上下颌骨骨骼关系可能是治疗后或长期下唇位置的预测因素。
