Cephalometric evaluation of adult anterior open bite non-extraction treatment with Invisalign

ABSTRACT Objective: The purpose of this study was to evaluate, by means of cephalometric appraisal, the vertical effects of non-extraction treatment of adult anterior open bite with clear aligners (Invisalign system, Align Technology, Santa Clara, CA, USA). Methods: Lateral cephalograms of 30 adult patients with anterior open bite treated using Invisalign (22 females, 8 males; mean age at start of treatment: 28 years and 10 months; mean anterior open bite at start of treatment: 1.8 mm) were analyzed. Pre- and post-treatment cephalograms were traced to compare the following vertical measurements: SN to maxillary occlusal plane (SN-MxOP), SN to mandibular occlusal plane (SN-MnOP), mandibular plane to mandibular occlusal plane (MP-MnOP), SN to mandibular plane (SN-MP), SN to palatal plane (SN-PP), SN to gonion-gnathion plane (SN-GoGn), upper 1 tip to palatal plane (U1-PP), lower 1 tip to mandibular plane (L1-MP), mesiobuccal cusp of upper 6 to palatal plane (U6-PP), mesiobuccal cusp of lower 6 to mandibular plane (L6-MP), lower anterior facial height (LAFH), and overbite (OB). Paired t-tests and descriptive statistics were utilized to analyze the data and assess any significant changes resulting from treatment. Results: Statistically significant differences were found in overall treatment changes for SN-MxOP, SN-MnOP, MP-MnOP, SN-MP, SN-GoGn, L1-MP, L6-MP, LAFH, and OB. Conclusions: The Invisalign system is a viable therapeutic modality for non-extraction treatment of adult anterior mild open bites. Bite closure was mainly achieved by a combination of counterclockwise rotation of the mandibular plane, lower molar intrusion and lower incisor extrusion.

摘要
研究目的：本研究旨在通过头影测量评估（cephalometric appraisal），明确采用隐适美系统（Invisalign system，Align Technology，美国加利福尼亚州圣克拉拉市）开展成人前牙开𬌗（anterior open bite）非拔牙矫治的垂直向矫治效果。
研究方法：选取30例接受隐适美系统治疗的成人前牙开𬌗患者的头颅侧位片（lateral cephalograms）进行回顾性分析，其中女性22例、男性8例；患者治疗初始时平均年龄为28岁10个月，初始平均前牙开𬌗度为1.8mm。对所有患者治疗前后的头颅侧位片进行描记，对比以下垂直向测量指标：前颅底平面-上颌牙合平面夹角（SN-MxOP）、前颅底平面-下颌牙合平面夹角（SN-MnOP）、下颌牙合平面-下颌平面夹角（MP-MnOP）、前颅底平面-下颌平面夹角（SN-MP）、前颅底平面-腭平面夹角（SN-PP）、前颅底平面-下颌角-颏顶点平面夹角（SN-GoGn）、上颌切牙切端至腭平面距离（U1-PP）、下颌切牙切端至下颌平面距离（L1-MP）、上颌第一恒磨牙近中颊尖至腭平面距离（U6-PP）、下颌第一恒磨牙近中颊尖至下颌平面距离（L6-MP）、下颌前部面高（LAFH）及覆𬌗度（OB）。采用配对t检验（Paired t-tests）与描述性统计（descriptive statistics）方法对数据进行分析，以评估治疗带来的显著变化。
研究结果：统计分析显示，SN-MxOP、SN-MnOP、MP-MnOP、SN-MP、SN-GoGn、L1-MP、L6-MP、LAFH及OB的整体治疗前后差异均具有统计学意义。
研究结论：隐适美系统是用于成人轻度前牙开𬌗非拔牙矫治的可行治疗方案。咬合闭合主要通过下颌平面逆时针旋转、下颌磨牙压低及下颌切牙伸长的协同作用实现。