Department of Medical, Surgical and Health Sciences, University of Trieste, Piazza Ospitale 1, 34129, Trieste, Italy.
Orthodontic Department, Dental School, University of Genoa, Genoa, Italy.
Prog Orthod. 2022 Aug 15;23(1):27. doi: 10.1186/s40510-022-00423-6.
The introduction in the orthodontic field of the digital workflow for guided insertion of palatal TADs and the development of the 1-visit protocol led to the reduction of chair time and the possibility of complete customization of designs and materials. Conversely, the reduction of operative steps implicates a lower tolerance of deviations between the planned and the actual position of the miniscrews, particularly when the orthodontic device is fixed on 4 palatal TADs or has a rigid structure. This study aims to analyze the influence of each step of the digital workflow on the deviation of the miniscrews' axis of insertion in a bicortical sample. The null hypothesis is that there are no significant differences in the deviations among the operative steps.
33 subjects were selected for insertion of bicortical palatal miniscrews with a 1-visit protocol. Digital files were collected at the three stages of the workflow (i.e., digital planning, laboratory prototype, post-insertion impression). A 3D software analysis was performed on a total of 64 miniscrews. After automatic shape recognition of the guiding holes of the digital plan and the scanbodies of the laboratory prototype and post-insertion impression as geometric cylinders, their three-dimensional longitudinal axis was traced and the deviation among them was calculated. Friedman test with Bonferroni correction was performed to assess the significance of the deviations among the three steps, with significance set at p < 0.05.
The laboratory step has a significantly lower degree of deviations (2.12° ± 1.62) than both the clinical step (6.23° ± 3.75) and the total deviations (5.70° ± 3.42). No significant differences were found between miniscrews inserted on the left or the right side.
This study suggests that laboratory procedures such as surgical guide production or rapid prototyping don't play a significant role in the degree of deviations between the planned and the positioned palatal TADs. Conversely, the clinical steps have a bigger influence and need to be carefully evaluated. Despite this difference, there is a cumulative effect of deviations that can lead to the failure of the 1-visit protocol.
在正畸领域引入导弓辅助植入腭部微型种植体的数字化工作流程，以及发展单次就诊方案，这使得椅旁时间得以减少，同时也使设计和材料的完全定制化成为可能。然而，操作步骤的减少意味着对计划与实际微型种植体植入位置之间偏差的容忍度降低，尤其是当正畸装置固定于 4 个腭部微型种植体或具有刚性结构时。本研究旨在分析数字化工作流程的每一步骤对双皮质腭部微型种植体植入轴偏差的影响。零假设是各个操作步骤之间的偏差无显著差异。
选择 33 例患者进行单次就诊方案下的双皮质腭部微型种植体植入。在工作流程的三个阶段（即数字化设计、实验室模型、植入后印模）收集数字文件。对总共 64 个微型种植体进行三维软件分析。在自动识别数字化设计中的引导孔和实验室模型以及植入后印模的扫描体的形状为几何圆柱体后，追踪其三维纵向轴，并计算它们之间的偏差。采用 Friedman 检验（Bonferroni 校正）评估三个步骤之间偏差的显著性，显著性水平设置为 p<0.05。
实验室步骤的偏差程度（2.12°±1.62）显著低于临床步骤（6.23°±3.75）和总偏差（5.70°±3.42）。左侧和右侧植入的微型种植体之间无显著差异。
本研究表明，实验室操作，如手术导板制作或快速成型，对计划与定位的腭部微型种植体之间的偏差程度影响不大。相反，临床步骤的影响更大，需要仔细评估。尽管存在这种差异，但偏差具有累积效应，可能导致单次就诊方案失败。
