AN ANALITICAL EVALUATION OF PERIODONTAL TISSUE CHANGE WITH DAMPED OSCILLATION OF TEETH.

特别是牙齿活动度的测量被认为是直接显示牙周组织状况和功能的主要技术，本研究旨在建立一种新的方法来客观评价包括牙齿活动度在内的牙周组织特征。在临床研究之前，它使用了具有可调节的牙根锥度和牙根周围减震材料厚度的人工牙模型。考察了阻尼振荡、弹性常数、粘滞常数及弹性与粘滞常数之比等因素对阻尼振荡的影响。这些数据被用来探讨他们是否有助于客观评价牙周组织的特点。研究结果如下：（1）通过对牙体模型在水平和垂直载荷作用下，在加速度计上选择的波形进行分析，得出了上述结果。(2)推导出了弹性模量的理论计算公式，并考虑了弹性常数和粘滞常数对临床应用的影响。(3)无论是水平还是垂直洛丁作用下，单根阻尼振动、弹性常数、粘滞常数以及弹粘比均随根系锥度的增大而减小。(4)在垂直洛丁作用下，根底吸震材料厚度增加，根底吸震材料的阻尼振动、弹性常数、粘滞常数及粘弹比均减小。

In particular, the measurement of tooth mobility is concidered a majior technique for demonstrating the conditions and functions of periodontal tissue directly.The aim of this study is to establish a new method to evaluate periodontal tissue characteristics objectively, including tooth mobility. In advance of clinical study, it used artificial tooth model with adjustable root tapers and thickness of a shock-absorbing material around the root. Factors investngated included individual damped oscillation, elastic constants, viscositic constants and the ratio of the elastic and viscositic constant. The data were used to explore whether they contribute to objective evaluation of the characteristics of periodontal tissue. The results were as follows :(1) These were obtained from analysis of the wave forms selected on an accelemeter when the tooth model was loaded horizontally and vertically.(2) A theoretical formula of the accelation was derived, and the elastic and viscositic constants were considered with regard to clinical use.(3) In cases of both horizontal and vertical loding, individual damped oscillation, elastic constants, viscositic constants and the ratio of the elastic and viscositic constants showed a tendency to decrease as the taper of the root increased.(4) In case of vertical loding, the value of individual damped oscillation, elastic constants, viscositic constants and the ratio of the elastic and viscositic constants decreased as the thickness of the shock absorbing material on the botom of root increased.