Kimura H, Sohmura T, Watanabe T
Shika Zairyo Kikai. 1989 Nov;8(6):877-82.
A three dimensional shape measurement using a wide area teeth model was constructed using a high precision laser displacement meter, teeth model scanning machine and personal computer. The system employed a Z-directional movement of a laser displacement meter which tracked wide and complicated changes of shape, allowing for the accurate measurement of not only the crown and alveolar crista of the molar, but also maxillary root, the height difference between which extends about 25mm. As for the labialis of the incisors, teeth model was stood on a gonio stage and measured. In the present study, arrange arc and rugged array of incisors were measured. Improvements in the accuracy of measurement were also expected. Higher resolutions were obtained by the measurement at the center of the measurable range of the displacement meter where the laser beam is most focused. Since the lineality of the measured value varies with the sensitivity coefficient, if the coefficient drifted, values measured in the outer measurable ranges yielded large errors than those in the central positions. The present Z-directional movement enables measurement at the center of the measurable range, yielding smaller errors. The data obtained with the present method of Z-directional movement of a laser displacement meter enables not only the precise measurement of the shape and position of teeth for CAD prosthesis design but also provides basic data for simulation of occlusion by adding the relative positions of the maxilla and mandible to computer models.
使用高精度激光位移计、牙齿模型扫描仪和个人计算机构建了一种基于大面积牙齿模型的三维形状测量系统。该系统采用激光位移计在Z方向上移动，以跟踪广泛而复杂的形状变化，不仅能够精确测量磨牙的牙冠和牙槽嵴，还能测量上颌牙根，其上颌牙根之间的高度差约为25毫米。对于切牙的唇面，将牙齿模型放置在测角台上进行测量。在本研究中，测量了切牙的排列弧度和凹凸阵列。同时也期望提高测量精度。通过在位移计可测量范围的中心进行测量可获得更高的分辨率，在该中心激光束聚焦效果最佳。由于测量值的线性度会随灵敏度系数而变化，如果该系数发生漂移，那么在可测量范围边缘测量的值会比中心位置测量的值产生更大的误差。目前的Z方向移动能够在可测量范围的中心进行测量，从而产生较小的误差。通过激光位移计的这种Z方向移动方法获得的数据，不仅能够为CAD义齿设计精确测量牙齿的形状和位置，还能通过将上颌骨和下颌骨的相对位置添加到计算机模型中，为咬合模拟提供基础数据。
