A Clinical, Periodical and Physiological Evaluation of Changes in Masticatory Load Center and Function

本研究的目的是评价RPD对单侧弓缩短和咬合重建的影响，通过肌电和预测来阐明咬合接触分布与咀嚼肌肉活动负荷中心位置的关系。采用超薄层压力计（Prescale Fuji Film Co.）测量咬合接触分布、负荷分布及负荷中心位置，采用专用计算机分析系统记录咀嚼活动和咬合接触肌电图。十双边缩短arch-cases被用作控制和十五单边缩短牙科拱门联系人在单边缩短弧prosthdontic治疗之后,那些咬合的负载,坐标的点和数量,咀嚼功能的关系进行了研究在前后RPD定期治疗。将这些数据与对照组进行分析和评价。这些结果的概要如下：1)齿状口的咬合负荷中心位置在上颌第一磨牙区中线左右，而单侧缩短弓的咬合负荷中心偏前约1个前磨牙宽度，并向左齿状侧倾斜。2)单侧短弓牙槽的支撑区中心偏向残侧，稍偏向切弓。3)佩戴符合设计要求的RPD约1年后，在单侧齿状弧形中，负荷中心位置改善为齿状弧形，假定生理和功能恢复，并激活咀嚼肌肉。4) 1年零2个月的随访结果显示，单侧无牙病例（单侧弓缩短）的修复在临床和生理上都是非常有效的。

The aim of the study was to evaluate the unilateral shortened arch and occlusal rconstruction by RPD to elucidate relation between distribution of occlusal contacts and location of load center of masticatory musculature activities by EMG and Prescale.Distnbution of occlusal contacts and those loads, also location of load center were measured by extra-thin-layer of pressure indicator (Prescale Fuji Film Co.), with an exchusive analyzing computer system EMG of masticatory activities and occlusal contacts were recorded with Prescale at IP clenching. Ten bilateral shortened arch-cases were used as control and fifteen unilateral shortened dental arches contacts in unilateral shortened arc and after prosthdontic treatments, those occlusal loads, coordinates of the points and amounts, in relation masticatory functions were studied in periodically at pre and post RPD treatments. These data were analyzed and evaluated in those of control group. The outlines of these results were as follows ;I) The location of the occlusal load center in dentate mouth was in about median line of the maxillar first molar region, but in unilateral shortened arch the load center was biased about one premolar breadth anteriorly and inclined toward nemaining dentate side.2) The center of supporting area of unilateral shortened arch edentation was biased toward remaining side and slightly to incisal arch.3) Then after wearing eligible designed RPD for about one year, in unilateral edentate arc, the location of load cnter was improved as dentate arc, presuming physiological and functional recovery, and also activated masticatory musculatures.4) The prosthodontic restoration for unilateral edentate cases (unilateral shortened arch) was quite effective in clinical and physiological standpoints from the follow-up results in one year and 2 months.