A. T. Still University, Mesa, Arizona 85206, USA.
Am J Orthod Dentofacial Orthop. 2010 Sep;138(3):262.e1-262.e11; discussion 262-3. doi: 10.1016/j.ajodo.2010.02.023.
The purpose of this study was to evaluate the efficacy of the Schwarz appliance with a new method of superimposing detailed cone-beam computed tomography (CBCT) images.
The subjects were 28 patients with Angle Class I molar relationships and crowding; they were randomly divided into 2 groups: 14 expanded and 14 nonexpanded patients. Three-dimensional Rugle CBCT software (Medic Engineering, Kyoto, Japan) was used to measure 10 reference points before treatment (T0) and during the retention period of approximately 9 months after 6 to 12 months of expansion (T1). Cephalometric and cast measurements were used to evaluate the treatments in both groups. Also, the mandibular widths of both groups were measured along an axial plane at 2 levels below the cementoenamel junction from a CBCT scan. Differences between the 2 groups at T0 and T1 were analyzed by using the Mann-Whitney U test.
The dental arch (including tooth root apices) had expanded; however, alveolar bone expansion was only up to 2 mm below the cementoenamel junction. There was a statistically significant (P <0.05) difference between the groups in terms of crown, cementoenamel junction, root, and upper alveolar process. However, no significant (P >0.05) differences were observed in the interwidths of the mandibular body, zygomatic bones, condylar heads, or mandibular antegonial notches. In the mandibular cast measurements, arch crowding and arch perimeter showed statistically significant changes in the expanded group. The buccal mandibular width and lingual mandibular width values had significant changes as measured from a point 2 mm below the cementoenamel junction.
The findings suggest that the Schwarz appliance primarily affected the dentoalveolar complex, but it had little effect on either the mandibular body or any associated structures. In addition, the molar center of rotation was observed to be below the root apex.
本研究旨在评估 Schwarz 矫治器与一种新的详细锥形束 CT（CBCT）图像叠加方法相结合的疗效。
研究对象为 28 名 Angle Ⅰ类磨牙关系和拥挤患者，随机分为扩弓组和非扩弓组各 14 例。采用三维 Rugle CBCT 软件（日本京都 Medic Engineering）测量治疗前（T0）和扩弓后 6-12 个月保持期约 9 个月（T1）的 10 个参考点。对两组患者进行头影测量和模型测量。同时，在 CBCT 扫描的釉牙骨质界下方 2 个水平处，沿矢状面测量两组下颌骨宽度。使用 Mann-Whitney U 检验分析两组 T0 和 T1 之间的差异。
牙弓（包括根尖）扩张，但牙槽骨仅扩张至釉牙骨质界下方 2mm。牙冠、釉牙骨质界、牙根和上颌牙槽突在两组间存在统计学差异（P＜0.05）。然而，下颌体、颧骨、髁突和下颌前结节间宽度无统计学差异（P＞0.05）。在颌骨模型测量中，扩弓组的牙弓拥挤和牙弓周长发生了统计学显著变化。从釉牙骨质界下方 2mm 处测量，颊舌向下颌宽度值发生了显著变化。
结果表明 Schwarz 矫治器主要影响牙牙槽复合体，但对下颌体或任何相关结构影响较小。此外，磨牙旋转中心位于根尖下方。
