Development of new articulator with six degrees of freedom jaw movement replicating system

目的研制一种能在六个自由度上动态再现下颌运动的新型咬合架。方法选择一名健康成年志愿者（男，31岁），在其左侧上颌第一磨牙行全冠修复。根据德岛大学牙科医院的标准方法进行牙体预备和取模。在知情同意后，使用六自由度下颌跟踪仪（BS-3）测量受试者的下颌运动。将记录的颌骨运动附着在工作模型的基牙上，并将该模型固定在HEXAPOD的定位台上。在下颌运动复制过程中，在牙合台上方的FGP蜡上雕刻对侧牙牙合面的功能通路。结果与讨论BS-3测量的下颌运动数据平移精度为10 μ m，旋转精度为0.001 °。HEXAPOD可以精确地控制定位平台在0.5-1.0 μ m的水平上平移和1.0 arcsec（0.000278度）的旋转，因此可以执行测量的颌运动的完全重新定位。由于牙周组织的存在，铸石模型不具有弹性，在下颌运动的闭合阶段，模型可能会破裂。因此，我们采用硅橡胶印模材料作为减震材料，固定上牙体模型，从而证明新型六自由度牙合架适用于设计功能性义齿牙合面。

OBJIETIVE The purpose of this research is to develop a new articulator that performs dynamic replication of jaw movement in six degrees of freedom.METHOD A healthy adult volunteer (male, 31 years old) who palaned to have full cast crown restoration on his left side upper first molar was selected as the subject. Clinical procedures for tooth preparation and taking impression were performed according to the standard methods of Tokushima University Dental Hospital. After taking informed consent, jaw monement of the subject was measured with six degrees of freedom jaw tracking device (BS-3). The recorded jaw movements were attached on the abutment tooth of working model, and this model was fixed on the positioning stage of HEXAPOD. During replication of jaw movement, functional pathway of opposite tooth occlusal surfacewas carved on FGP wax above occlusal table. Functional core was taken from the occlusal table, and FGP srticulator was used for waxing up of full veneer crown.RESULTS AND DISCUSSION Jaw movement data that measured by BS-3 is accurate to level of 10 um for translation and 0.001 degrees for rotation. HEXAPOD can control positioning stage precisely at level of 0.5-1.0 um for translation and 1.0 arcsec (0.000278 degrees) for rotation, so complete replocation of the measured jaw movements could be performed. Since cast stone cast stone model dose not have elasticity due to the periodontal tissue, the model could be broken during closing phase of jaw movement. So we applied silicone rubber impression material as shock absorber for attaching upper cast stone model.It could be concluded that the new six degrees of freedom articulator was applicable for designing functional occlusal surface of dental prosthesis.