LaBlonde Brian, Vich Manuel Lagravere, Edwards Paul, Kula Katherine, Ghoneima Ahmed
School Dentistry, Indiana University, Indianapolis, IN, USA.
University of Alberta, Edmonton, Canada.
Dental Press J Orthod. 2017 Feb;22(1):89-97. doi: 10.1590/2177-6709.22.1.089-097.oar.
The aim of this multi-center retrospective study was to quantify the changes in alveolar bone height and thickness after using two different rapid palatal expansion (RPE) activation protocols, and to determine whether a more rapid rate of expansion is likely to cause more adverse effects, such as alveolar tipping, dental tipping, fenestration and dehiscence of anchorage teeth.
The sample consisted of pre- and post-expansion records from 40 subjects (age 8-15 years) who underwent RPE using a 4-banded Hyrax appliance as part of their orthodontic treatment to correct posterior buccal crossbites. Subjects were divided into two groups according to their RPE activation rates (0.5 mm/day and 0.8 mm/day; n = 20 each group). Three-dimensional images for all included subjects were evaluated using Dolphin Imaging Software 11.7 Premium. Maxillary base width, buccal and palatal cortical bone thickness, alveolar bone height, and root angulation and length were measured. Significance of the changes in the measurements was evaluated using Wilcoxon signed-rank test and comparisons between groups were done using ANOVA. Significance was defined at p ≤ 0.05.
RPE activation rates of 0.5 mm per day (Group 1) and 0.8 mm per day (Group 2) caused significant increase in arch width following treatment; however, Group 2 showed greater increases compared to Group 1 (p < 0.01). Buccal alveolar height and width decreased significantly in both groups. Both treatment protocols resulted in significant increases in buccal-lingual angulation of teeth; however, Group 2 showed greater increases compared to Group 1 (p < 0.01).
Both activation rates are associated with significant increase in intra-arch widths. However, 0.8 mm/day resulted in greater increases. The 0.8 mm/day activation rate also resulted in more increased dental tipping and decreased buccal alveolar bone thickness over 0.5 mm/day.
这项多中心回顾性研究的目的是量化使用两种不同的快速腭扩展（RPE）激活方案后牙槽骨高度和厚度的变化，并确定更快的扩展速率是否可能导致更多不良反应，如支抗牙的牙槽倾斜、牙齿倾斜、开窗和骨裂。
样本包括40名受试者（年龄8 - 15岁）在接受RPE治疗前后的记录，这些受试者使用四带式Hyrax矫治器作为正畸治疗的一部分来纠正后牙颊向反合。根据RPE激活速率将受试者分为两组（0.5毫米/天和0.8毫米/天；每组n = 20）。使用Dolphin Imaging Software 11.7 Premium对所有纳入受试者的三维图像进行评估。测量上颌基骨宽度、颊侧和腭侧皮质骨厚度、牙槽骨高度以及牙根角度和长度。使用Wilcoxon符号秩检验评估测量值变化的显著性，并使用方差分析进行组间比较。显著性定义为p≤0.05。
每天0.5毫米（第1组）和每天0.8毫米（第组）激活速率导致治疗后牙弓宽度显著增加；然而，第2组比第1组增加幅度更大（p < 0.01）。两组的颊侧牙槽高度和宽度均显著降低。两种治疗方案均导致牙齿颊舌向角度显著增加；然而，第2组比第1组增加幅度更大（p < 0.01）。
两种激活速率均与牙弓内宽度的显著增加相关。然而，0.8毫米/天导致的增加幅度更大。0.8毫米/天的激活速率还导致牙齿倾斜增加更多以及颊侧牙槽骨厚度比0.5毫米/天减少更多。
