Assessment of visco-elasticity of the periodontium by means of simultaneous recording fo tooth oscillation and peripheral circulation

由于血液流经牙周膜的毛细血管，牙齿会发生脉动。本研究的目的是通过使用非晶态磁芯多谐振荡器传感器测量牙齿的摆动，获得一个评价牙周组织外周循环和粘弹性的指标。(1)唇舌方向的平均幅度(0.59微米)及其变化小于牙轴方向(0.88微米)。(2)牙齿搏动晚于R波后0.11~0.13秒。(3)唇面3个测量点在16颗牙中移动方向一致，其余3个测量点走势不同。(4)观察到两种功率谱模式。一种是频谱功率随着频率的增加而逐渐减小，另一种是频谱中间出现凹陷。第二，通过测量牙齿移动开始时的牙齿摆动，估计在第一前磨牙移动一个月后，左上尖牙分别受到0、20、60和120g的正畸力推动的可能性。静息0g时，脉搏与心率同步，幅度为0.15微米。在20克的力作用下，振幅略有增加。这表明受压的牙周膜下的血流仍然是安全的。在60克和120克的力下，振幅分别接近0.1微米和0.05微米以下。这一下降幅度表明，随着作用力的增加，牙周膜的血流受阻。

The tooth pulsates due to blood flow through capillary vessels of the periodontal membrane. The purpose of the present research was to obtain an index for assessment of the peripheral circulation and visco-elasticity of the periodontium through the measurement of tooth oscillation with an Amorphous core multivibrator senser.First, to obtain the norm of tooth oscillation of the unaffected periodontium, the recordings of 23 central incisors with healthy periodontal membrane were analyzed. (1) The mean amplitude of the labio-lingual derection (0.59mum) and the variations were smaller than the tooth axis deirection (0.88mum) . (2) The tooth pulsated as late as 0.11-0.13 sec after R-wave of electrocardiograph. (3) The three measurement points at the labial surface moved in a similar direction in 16 teeth, and showed different trends in the others. (4) Two patterns of the power spectrum were observed. One in which the power of the spectrum decreased gradually with increased frequency, the other was that the depression is seen at the midst of the spectrum.Second, the possibility of the index of the optimum force were estimated from the measurement of tooth oscillation at the beginning of the tooth movement, a month after the first premolar, the upper left canine were pushed by the orthodontic force of about 0,20,60 and 120 grams. At resting condition of 0 gram, the pulsation synchronized with the heart rate in which the amplitude was 0.15 mum. The amplitude at the force of 20 grams increased slightly. This suggested that the blood flow was still secured under the pressed periodontal membrane. At the force of 60 and 120 grams, the amplitudes were almost 0.1 and under 0.05 mum, respectively. This decreased amplitude indicated that the blood flow in the periodontal membrane was impeded as the force imcreased.