Development of measurement system for viscoelasticity of periodontium and peri-implantium.

我们先前已经开发了一个自动诊断系统的牙齿移动，测量人类牙周组织的生物力学性能。我们报道了日本人牙周膜粘弹性的正常范围。然而，关于不同种族间牙周组织粘弹性差异的研究报道较少。我们选择了44名中国人和57名日本人的88颗和93颗健康中切牙，年龄分别为20岁。结果表明，不同种族间牙周组织的粘弹性存在差异。由于该系统的阻抗头太大，无法测量种植体基台和磨牙的活动度，因此开发了一种称为T-M测试仪的简化测试仪器。对齿面施加单频振动，测量加速度响应，然后计算齿的机械活动度。牙位移传感器的探头采用了一套双压电晶片压电陶瓷盘。因此，它体积小，重量轻，适合口腔检查。用人工模型证实了传感器的基本特性和测量探头的临床适用性。用T-M粘弹仪测定种植体牙周组织和种植体周围组织粘弹特性的差异。结果表明：用T-M测试仪测量注入迁移率是可行的。种植体的活动度指数评分小于牙齿。我们应用T-M测试仪的相同原理，开发了种植体移动（IM）检查器。我们使用人工牙模型和种植体模型验证了它的性能。新研制的I-M检查器具有足够的测量可靠性，可以在牙科临床中客观地估计种植体的移动。

We have previously developed an automatic diagnostic system for tooth mobility, for measuring the biomechanical properties of human periodontium. We have reported the normal range of viscoelasticity of the periodotum in Japanese. However, there were few reports about a difference of the viscoelasticity of the periodontium between races. We selected 88 and 93 healthy central incisors of 44 Chinese and 57 Japanese aged 20s, respectively. In conclusion, it was suggested that the viscoelasticity of the periodontium was different between races. Since the impedance head of the system is too large to measure mobility in an implant abutment and a molar, a simplified testing instrument called T-M tester was developed. A single-frequency vibration is applied to the tooth surface, an acceleration response is measured, and then the mechanical mobility of the priodontium is calculated. The tooth-movement transducer of the probe utilized a set of bimorph piezoelectric ceramic disks. It is therefore small, light, and suitable for oral examination. The basic characteristics of transducer and clinical applicability of the measurement probe were confirmed using an artificial model. The T-M tester was applied to implants to determine the difference of viscoelastic properties between periodontium and peri-implantium. The obtained results were as follows : it was possible to measure the implant mobility by T-M tester. Mobility-Index scores of the implants were smaller than those of teeth. We applied the same principle of T-M tester and developed an Implant Movement (IM) checker. We verified its performance by using artificial tooth models and implant models. The newly developed I-M checker had sufficient measuring reliability and we could objectively estimate the implant movement in dental clinics.