Milad Saif-Alnasr Abdullah, Hussein Farouk Ahmed, Mohammed Al-DanyAtwa, Hashem Mohamed I
Department of Orthodontics, Faculty of Dental Medicine (Boys), Al-Azhar University, Cairo, Egypt.
Dental Biomaterials Research Chair, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
Saudi J Biol Sci. 2020 Feb;27(2):727-735. doi: 10.1016/j.sjbs.2019.12.008. Epub 2019 Dec 17.
The aim of this clinical study was to evaluate and compare the dentoskeletal transverse mandibular arch dimensions following the use of two designs of fixed mandibular expanders using cone beam computed tomography (CBCT). Twenty orthodontic patients, 12 females and 8 males, with mean age of 13.4 ± 0.5 years were selected and randomly divided into two equivalent groups; group A consisted of 10 patients (4 boys, 6 girls) who were treated with modified Williams expander and group B consisted of 10 patients (4 boys, 6 girls) who were treated with a two-arm fixed expander. Consistent expansion instructions were given to all patients according to a standardized slow protocol of one quarter turn twice/week for both expanders. Routine orthodontic records as well as mandibular CBCTs were obtained before (T1) and immediately after expansion (T2) to estimate changes in dentoskeletal mandibular transverse dimensions. The data was statistically analyzed and the significance level was set at ≤ 0.05. Mandibular intercanine, inter-premolar, intermolar widths; and arch perimeter were significantly increased ( ≤ 0.05) following expansion with both fixed expanders. However, the changes in inter-premolar width, intercanine width, and arch perimeter were significantly augmented in two-arm fixed expander group than modified Williams's group. In contrast, their effects on the skeletal mandibular body width were non-significant ( > 0.05). Both expanders yielded significant and equivalent dentoalveolar effects that were more evident with two-arm fixed expander than the William one. Both fixed designs enhanced mandibular transverse dental dimensions; however, they were unsuccessful to create any considerable skeletal effects.
本临床研究的目的是使用锥形束计算机断层扫描（CBCT）评估和比较两种固定下颌扩弓器设计使用后下颌牙-骨骼横向弓维度。选取20例正畸患者，12例女性和8例男性，平均年龄13.4±0.5岁，随机分为两个相等的组；A组由10例患者（4名男孩，6名女孩）组成，他们接受改良威廉姆斯扩弓器治疗，B组由10例患者（4名男孩，6名女孩）组成，他们接受双臂固定扩弓器治疗。根据两种扩弓器均为每周两次、每次四分之一圈的标准化慢速方案，向所有患者给出一致的扩弓指导。在扩弓前（T1）和扩弓后即刻（T2）获取常规正畸记录以及下颌CBCT，以评估下颌牙-骨骼横向维度的变化。对数据进行统计学分析，显著性水平设定为≤0.05。使用两种固定扩弓器扩弓后，下颌尖牙间、前磨牙间、磨牙间宽度以及牙弓周长均显著增加（≤0.05）。然而，双臂固定扩弓器组在前磨牙间宽度、尖牙间宽度和牙弓周长方面的变化比改良威廉姆斯组显著增大。相比之下，它们对下颌骨体宽度的影响不显著（>0.05）。两种扩弓器均产生了显著且等效的牙-牙槽效应，双臂固定扩弓器比威廉姆斯扩弓器更明显。两种固定设计均增强了下颌横向牙维度；然而，它们未能产生任何显著的骨骼效应。
