Center of Digital Dentistry, Faculty of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, PR China.
Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, PR China.
J Prosthodont. 2022 Oct;31(8):663-672. doi: 10.1111/jopr.13529. Epub 2022 May 18.
To establish a direct digital method for determining and recording edentulous maxillomandibular relationship using a custom-made jaw movement tracking system and evaluate its accuracy.
A novel jaw tracking system was used to record the trajectory of habitual opening-closing jaw movement, and mandibular rest position (MRP) in 10 edentulous patients. 3D surface scanning was performed on the conventional maxillomandibular impressions and facial structures of patients in MRP. The multisource data were registered using a custom-made recording tool. A plane parallel to the ala-tragus and horizontal lines was constructed 2 mm above the MRP, and its vertical position was used to determine the vertical relationship. The intersections of the trajectory passing through the plane were located, and their density distributions were analyzed. The coordinates of highest density, which presented the highest repeatability of jaw movement, were used to construct the digital maxillomandibular relationship (test group). The maxillomandibular relationship of the new complete dentures with artificial teeth in the intercuspal position was defined as the control group. The displacements of the anterior reference point and 3D deviations of the entire mandibular arch were measured and compared between the test and control groups using a Wilcoxon signed-ranks test and a one-sample t-test, respectively.
With reference to the centric relationship position, the maximum displacements of the anterior reference points were in the horizontal anteroposterior direction for both groups, and there were no significant differences. Compared to the control group, the 3D deviations of the entire mandibular arch in the test group were significant (95% confidence interval: 0.76 mm to 1.35 mm, p < 0.001).
By analyzing the individual trajectory features obtained by the in-house developed jaw tracking system, a digital method for determining and recording edentulous maxillomandibular relationships was established; however, the accuracy needs to be further improved.
使用定制的下颌运动跟踪系统建立直接数字化方法来确定和记录无牙颌上下颌关系，并评估其准确性。
使用新型下颌跟踪系统记录 10 名无牙颌患者习惯性开闭下颌运动轨迹和下颌休息位（MRP）。对患者 MRP 下的常规上下颌印模和面部结构进行 3D 表面扫描。使用定制记录工具对多源数据进行配准。构建一个与翼-外耳平面平行且高于 MRP 2mm 的平面，使用其垂直位置确定垂直关系。定位穿过平面的轨迹的交点，并分析其密度分布。使用呈现出最高下颌运动可重复性的最高密度坐标构建数字化上下颌关系（实验组）。将具有正中关系位人工牙的新全口义齿的上下颌关系定义为对照组。使用 Wilcoxon 符号秩检验和单样本 t 检验分别测量和比较实验组和对照组的前参考点的位移和整个下颌弓的 3D 偏差。
以正中关系位为参考，两组前参考点的最大位移均在水平前后方向，无显著差异。与对照组相比，实验组整个下颌弓的 3D 偏差显著（95%置信区间：0.76mm 至 1.35mm，p<0.001）。
通过分析自主研发的下颌跟踪系统获得的个体轨迹特征，建立了一种用于确定和记录无牙颌上下颌关系的数字化方法，但准确性有待进一步提高。
