The three-dimensional display of mastication and the movement of occlusal contact point using a jaw movement analyzer (mandibular tracking device) and CAD software

Abstract

顎 運 動 に 関 す る 研 究 は，1984 年 に Lundeen と Gibbs 1) が，咀嚼運動や咬合接触点を再現するために 顎運動測定器を開発し，研究報告されてきた．日本で も種々の顎運動測定器を用いて運動解析した多くの研 究が報告されている 2-5) が，それらは数値化するにと どまり，顎運動を様々な角度からビジュアル化して 3 次元表示することはできなかった．現在では，口腔内 スキャナや CAD/CAM スキャナから読み取ったスタ Purpose: The purpose of this study was to reproduce three-dimensional chewing movements and the change of occlusal contact points by software. Materials and Methods:The study model was converted into the software as STL data from a CAD scanner. In addition, we recorded XML data of the mandibular border movement, opening and closing movements, and chewing movements using a six-degree-of-freedom jaw tracking device (ARCUS digma2, KaVo, Biberach, Germany). The XML data was converted to STL data, and we reproduced the three-dimensional chewing movements and occlusal contact points by the software. Discussion: Using the functional analysis program, it is possible to reproduce the border movements, opening and closing movements, and chewing movements in three dimensions. We could also observe the change of occlusal contact points in the chewing movements. We suggest that occlusal interference could be found or the temporo-mandibular joint could be examined in the future by using the software to analyze three-dimensional jaw movements. Conclusions:We succeeded in observing three-dimensional jaw movements from every angle by the software. In addition, the changes of occlusal contact points in chewing movements were reproduced.