Development of quantitative evaluation method for occlusal morphology and occlusal tooth contacts

本研究的总体目标是建立一种客观评价牙合的方法。以下是本研究项目的成果。用这笔预算购买的新的工作站计算机提高了口腔颌面诊断系统的数据处理速度。根据磨牙区咬合小关节的法向和位置，将其分为AM、AD、BM、BD、CM、CD六种不同类型。A、B、C代表各小平面的内侧位置及其法矢方向，M、D代表法矢的前后方向。结合咬合面的三维形态和6个自由度的颌面运动数据，分析咬合接触在咀嚼过程中的动态变化。用该方法计算了相对咬合面之间的距离和颌骨闭合运动轨迹的入射角。这些数值参数被用来评估…咀嚼时有更多的咬合接触。结果表明：(1)在咀嚼第四阶段，AM和CM型咬合面的相对咬合面之间的距离较短。2)咀嚼第四阶段时，下颌运动轨迹与AM、CM类小关节的夹角较小(约10°)。AD和CD型咬合面的夹角为20°~30°。3)BD型咬合面末端闭合运动的入射角为30°，BM型面为40°。4)在第五阶段，BD型咬合面相对咬合面的距离最小。在第四阶段的咀嚼运动中，下颌磨牙功能尖和相对上磨牙的AM型咬合面作为咀嚼运动的功能导向。这一发现表明，这些小面的功能特性是砂浆和研磨。另一方面，BD型咬合小关节对咀嚼行程的第五阶段起挤压、挤压和功能引导作用。本研究结果显示了合理的咬合小关节分类方法，揭示了各小关节的功能特性。这些结果为建立牙合接触的客观评价方法提供了有价值的数据。较少

Overall object of this research is to develop objective method for the evaluation of dental occlusion. Followings are outcomes of this research project.1. New workstation computer that was purchased with this budget improved data processing speed of stomatognathic diagnostic system.2. Occlusal facets on molar region were classified into six different types (AM, AD, BM, BD, CM, CD) according to the direction of its normal vector and its position. A, B and C represents medio-lateral position of each facet and direction of the normal vector of it, and M and D represents antero-posterior direction of the normal vector.3. Three-dimensional shape of occlusal surface and six degrees of freedom jaw movement data were combined to analyze dynamic transition of occlusal contacts '' during mastication. Distance between opposite occlusal surfaces and incident angle of the jaw closing f movement pathway were calculated with this method. These numerical parameters were utilized for the evaluation of … More occlusal contact during mastication. The results are as follows1) During fourth phase of chewing stroke, distance between opposing occlusal surfaces were shorter at AM and CM type occlusal facets. This tendency was remarkable at AM type facet on functional cusp of lower molar.2) During fourth phase of chewing stroke, angle between the jaw movement pathway and AM and CM type occlusal facets were relatively small (about 10 degrees). These angles of AD and CD type facets were ranged from 20 to 30 degrees.3) Incident angle of the terminal jaw closing movement was 30 degrees at BD type occlusal facet, and 40 degrees at BM type facet.4) During fifth phase of chewing stroke, distance between opposing occlusal surfaces was shortest at BD type occlusal facet. During fourth phase of chewing stroke, AM type occlusal facet on functional cusp of lower molar and opposing upper molar work as the functional guidance of masticatory movement. This finding suggest that functional property of these facets are mortaring and grinding. On the other hand, BD type occlusal facet works for squeezing, crushing and functional guidance for fifth phase of chewing stroke. The results of this study exhibit rational classification method for occlusal facet and functional properties of each occlusal facet were revealed. These findings provide valuable data to develop objective evaluation method for occlusal tooth contact. Less