Eurutairat Sawitt, Vongtiang Natnicha, Wonghinkong Sakda, Manopatanakul Somchai, Santiwong Peerapong, Viwattanatipa Nita
Candidate Master's Degree in Orthodontics, Faculty of Dentistry, Mahidol University, Bangkok, Thailand.
Private practice, Bangkok, Thailand.
BMC Oral Health. 2025 May 14;25(1):719. doi: 10.1186/s12903-025-05891-w.
The bowing effect observed during premolar extractions presents a challenge in clear aligner therapy. This study aims to investigate the accuracy of maxillary tooth movement in first premolar extraction cases using the in-house clear aligner (IHCA), comparing the palatal power arm (PA) and non-power arm (control / C).
Eighteen adults requiring maxillary first premolars extraction using IHCA were recruited. Using a randomized controlled trial with a split-mouth design, each patient received treatment for both PA and C. Data at the 24th IHCA comprising virtual-power arm (VPa), virtual-control (VC), actual-power arm (APa) and actual-control (AC) were measured by superimposition with pretreatment digital model, using 3D GOM Inspect software. Six types of tooth movement were assessed. Paired t-test or Wilcoxon signed-rank test was used to compare the differences between groups. Root mean square error (RMSE) as predictability was computed.
For the maxillary canine, there was no significant difference between the PA and C groups for all types of tooth movement except rotation. Specifically, the PA exhibited a significantly less difference in distal-in rotation compared to the control group (APa-VPa -3.54°/AC-VC -11.57°). Similarly, the RMSE of PA demonstrated better accuracy in rotation than the control (PA 7.85°/control 15.98°). In terms of anchorage, the RMSE of PA indicated greater deviation than the control in the second premolar mesial-in rotation and crown-tipping. Regarding the first molar, the RMSE of PA was mostly similar to that of the control.
IHCA can effectively retract maxillary canines in cases involving premolar extraction. However, although palatal power arms improve the accuracy of canine rotation, no notable benefits are seen for other types of tooth movement or for anchorage control.
Current Controlled Trials ISRCTN14020146 of the International Standard Randomized Controlled Trial. The date of registration was 16/11/2022. The trial was retrospectively registered.
前磨牙拔除过程中观察到的弓曲效应给隐形矫治带来了挑战。本研究旨在调查使用自制隐形矫治器（IHCA）进行上颌第一前磨牙拔除病例中牙齿移动的准确性，比较腭侧加力臂（PA）和非加力臂（对照组/C）。
招募了18名需要使用IHCA拔除上颌第一前磨牙的成年人。采用随机对照试验和分口设计，每位患者接受PA和C两组治疗。在第24副IHCA时的数据，包括虚拟加力臂（VPa）、虚拟对照组（VC）、实际加力臂（APa）和实际对照组（AC），通过使用3D GOM Inspect软件与治疗前数字模型叠加来测量。评估了六种牙齿移动类型。采用配对t检验或Wilcoxon符号秩检验比较组间差异。计算均方根误差（RMSE）作为可预测性指标。
对于上颌尖牙，除旋转外，PA组和C组在所有类型的牙齿移动方面均无显著差异。具体而言，与对照组相比，PA组在远中向旋转方面的差异明显更小（APa-VPa -3.54°/AC-VC -11.57°）。同样，PA组在旋转方面的RMSE显示出比对照组更高的准确性（PA 7.85°/对照组15.98°）。在支抗方面，PA组在第二前磨牙近中向旋转和牙冠倾斜方面的RMSE显示出比对照组更大的偏差。对于第一磨牙，PA组的RMSE大多与对照组相似。
在涉及前磨牙拔除的病例中，IHCA可有效内收上颌尖牙。然而，尽管腭侧加力臂提高了尖牙旋转的准确性，但在其他类型的牙齿移动或支抗控制方面未见明显益处。
国际标准随机对照试验的当前受控试验ISRCTN14020146。注册日期为2022年11月16日。该试验为回顾性注册。
