Studies on quantification of evaluation of dental occlusion

本研究旨在探讨牙合的定量评价方法。方法：受试者为健康志愿者（男3名，女3名，年龄22±2.27岁）。采用罗兰DC合作公司LPX-1200型三维激光扫描仪和牙模对受试者的咬合面进行数字化处理。使用新开发的6自由度下颌跟踪设备记录咀嚼过程中的下颌运动，该设备由一对双轴铣刀组成，并使用新开发的定制软件将这些数据链接到咀嚼过程中的咬合区域分析中。同时，采用水胶体压印材料法测定咀嚼效率，这是筛分试验的应用之一。试验食品为水胶体压印材料（Aromaloid, GC Corporation, Japan），尺寸为10mm（高）xl3mm（直径）-采用Spearman秩相关法评价咀嚼效率与咬合面积的关系。（SPSS 15.0J, SPSS Inc）。结果与讨论：咀嚼过程中累积咬合面积与咀嚼印模片数相关，但牙尖间位置的咬合面积与咀嚼效率相关性不明显。10次咀嚼时，距离在1000 ~ 1250 μm的咀嚼面积与咀嚼片数呈正相关，距离在250 μm以下的咀嚼面积与咀嚼片数呈负相关。而在咀嚼次数为20次时，250 μm距离断面下的咬合面积与咀嚼片数呈正相关。这些结果表明，没有功能运动就无法评估咬合，咀嚼过程中累积的咬合面积可以作为功能方面评估咬合的定量参数之一，但也表明咀嚼阶段对参数的定义非常重要。

The aim of this research was to investigate a quantitative evaluating method of dental occlusion. Methods: Subjects were healthy volunteers (males, female 3, avenged age 22±2.27). Occlusal surface of each subject were digitized with the 3D lazier scanner (Model LPX-1200, Roland DC cooperation) and dental casts. Jaw movements during mastication were recorded with a newly developed 6-degree-of freedom Jaw tracking device, which consisted of a pair of biaxial mils- Those data were linked to analyze occlusal area during mastication with a newly developed custom software. At the same time, masticatory efficiency was measured with a hydrocolloid impression material method, that was one of applications of the sieving test The test food was hydrocolloid impression material (Aromaloid, GC Corporation, Japan), the size of it was l0mm (height) xl3mm (diameter)- Spearman rank correlation was used to evaluate the relationship between masticatory efficiency and an area of occlusion. (SPSS 15.0J, SPSS Inc). Result and discussion: The cumulative area of occlusion during mastication was correlated with the number of pieces of chewed impression material, although the occlusal area at the intercuspal position was not correlated with the masticatory efficiency clearly. At 10 times chewing, occlusal area of 1000 to 1250 μm distance section was correlated with the number of pieces positively, while that of under 250 μm distance section was correlated with the number of pieces negatively. On the contrary, at 20 times chewing, occlusal area under 250 μm distance section was correlated with the number of pieces positively. Those results suggested that the occlusion could not be evaluated without functional movements, and cumulative area of occlusion during mastication could be one of quantitative parameters for evaluating occlusion in functional aspect But it also suggested that chewing phases are very important to formulate a definition of parameters.