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

本研究旨在通过RPD评价单侧短弓和咬合重建，以阐明咬合接触分布与EMG和Prescale咀嚼肌活动负荷中心位置的关系，采用超薄层压力指示器（Prescale Fuji Film Co.）测量咬合接触分布和负荷中心位置，应用计算机分析系统，用Prescale记录IP咬牙时咀嚼肌活动和咬合接触的肌电。以10例双侧短弓患者为对照组，15例单侧短弓患者为对照组，在单侧短弓修复治疗前后，定期研究RPD治疗前后的咬合负荷、点的坐标和量与咀嚼功能的关系。并与对照组进行对比分析。这些结果概述如下：（1）有牙颌口的咬合负荷中心位于上颌第一磨牙区的中线附近，而单侧短弓牙列的载荷中心偏向于前磨牙宽度的1倍左右，并偏向于向列齿状突侧; 2）单侧短弓牙列的支持区中心偏向于剩余侧，并略偏向于切弓戴用1年左右，单侧缺牙弧区负荷中心位置改善为缺牙弧区，提示生理功能恢复，同时咀嚼肌也得到激活。4）从1年2个月的随访结果来看，单侧缺牙（单侧短弓）的修复在临床和生理上都是有效的。

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.