Changes of facial actions in speaking and smiling by the dental treatment.

牙科治疗的目的之一是实现嘴唇周围的良好平衡。前牙的位置与嘴唇和周围环境的运动密切相关。例如，对于上颌牙齿前突的受试者，上唇即使在松弛状态下松动也需要强烈的张力才能闭合。下颌牙前突也不同于正常和上颌牙前突患者。然而，很难确定面部表情的治疗结果。首先，我们介绍了一种精确、高效的三维测量系统，该系统使用两个高速摄像头来分析面部表情。通过跟踪面部的6个标志物来分析面部动作。结果表明，“气”笑与自然笑基本一致，并呈现出一定的变化特征。另一方面，强迫微笑表现出与其他两种微笑不同的模式。没有情绪，微笑的面部表情是有些困难的。因此，我们认为在自然微笑的基础上，再加上自然微笑，可以用于面部表情的研究。通过对正常牙合的前牙打蜡法研究前牙覆盖与面部动作的关系，结果表明，前牙的位置强烈地影响嘴唇和周围环境的运动，并介绍了面部动作的三维显示程序。这一可视化系统将为牙医和患者之间提供一种沟通工具。

One of the purposes of dental treatments is achieving a well-balanced surroundings of lips. A position of anterior teeth is closely related to the movement of lips and the surroundings. For example,in case of subjects with maxillary teeth protrusion, strong tension of upper lip is necessary for closing even if it is loose in relax. Mandibular teeth protrusion is also different from normal and maxillary teeth protrusion subjects. However, it is quite difficult to determine the treatment results regarding facial expression. The first, we introduced a precise and efficient three-dimensional measurement system using two high speed cameras to analyze facial expression. Facial actions were analyzed by tracking 6 markers on the face. Results were as follows.'Chi'-smile was almost similar to natural smile which showed a characteristic patterns with some variations. On the other hand, forced smile showed different patterns from the other two smiles. Facial expression of smile is somewhat difficult without emotion. Therefore, it is considered that chi-smile in addition to natural smile can be used in studies of facial expressions.As the relationship between overjet of anterior teeth and a facial action by method of setting wax on anterior teeth of normal occlusion, the results suggested, that a position of anterior teeth strongly influenced the movement of lips and the surroundings.We also introduced a three dimensional display program of facial action. This visualizing system will contribute a communication tool between the dentists and patients.