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

目的研制一种能动态复制六自由度下颚运动的新型铰接器。方法选择一名健康成人志愿者（男性，31岁），拟行左侧上第一磨牙全铸造冠修复。按照德岛大学口腔医院标准方法进行牙体准备和印模的临床操作。在征得知情同意后，使用六自由度下颌跟踪装置（BS-3）测量受试者的下颌运动。将记录的下颌运动信息附着在工作模型的基牙上，将该模型固定在HEXAPOD的定位台上。在复制颌运动时，在咬合表上方的FGP蜡上刻下对牙咬合面功能通路。从咬合台上取下功能核，用FGP打蜡机对全冠进行上蜡。BS-3测量的下颌运动数据精确到平移10微米，旋转0.001度。HEXAPOD可以精确控制定位阶段在0.5-1.0 um的平移水平和1.0 arcsec（0.000278度）的旋转水平，因此可以完成测量的下颌运动的完全替换。由于铸石模型受牙周组织的影响不具有弹性，在颌部运动闭合阶段模型可能发生断裂。因此，我们采用硅橡胶压模材料作为减震器贴附上铸石模型。结果表明，该新型六自由度关节器可用于义齿功能咬合面设计。

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.