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
目的：本研究旨在通过头影测量（cephalometric appraisal）评估成人前牙开𬌗患者采用隐形矫治器（Invisalign系统，Align Technology公司，美国加利福尼亚州圣克拉拉）行非拔牙矫治的垂直向疗效。
方法：本研究分析了30例接受Invisalign矫治的成人前牙开𬌗患者的头颅侧位片（其中女性22例，男性8例；治疗起始平均年龄为28岁10个月；治疗初始平均前牙开𬌗度为1.8mm）。对治疗前后的头影测量片进行描记，以比较以下垂直向测量指标：蝶鞍点-鼻根点平面至上颌咬合平面的夹角（SN-MxOP）、蝶鞍点-鼻根点平面至下颌咬合平面的夹角（SN-MnOP）、下颌平面至下颌咬合平面的夹角（MP-MnOP）、蝶鞍点-鼻根点平面至下颌平面的夹角（SN-MP）、蝶鞍点-鼻根点平面至腭平面的夹角（SN-PP）、蝶鞍点-鼻根点平面至下颌角点-颏顶点平面的夹角（SN-GoGn）、上切牙切端至腭平面的距离（U1-PP）、下切牙切端至下颌平面的距离（L1-MP）、上颌第一磨牙近中颊尖至腭平面的距离（U6-PP）、下颌第一磨牙近中颊尖至下颌平面的距离（L6-MP）、下颌前部面高（LAFH）以及覆𬌗度（OB）。采用配对t检验与描述性统计学方法分析数据，评估治疗所引发的各项显著变化。
结果：研究发现，SN-MxOP、SN-MnOP、MP-MnOP、SN-MP、SN-GoGn、L1-MP、L6-MP、LAFH及OB的整体治疗变化均存在统计学显著性差异。
结论：Invisalign系统是治疗成人轻度前牙开𬌗的可行非拔牙矫治手段。咬合闭合主要通过下颌平面逆时针旋转、下颌后牙压低以及下切牙伸长的联合作用实现。