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

我们已经开发了一种自动诊断系统，用于测量人类牙周组织的生物力学特性。我们已经报道了日本人骨膜粘弹性的正常范围。然而，关于不同种族牙周组织粘弹性差异的报道很少。我们分别选择了44名20岁的中国人和57名20岁的日本人，分别选择了88名和93名健康中切牙。结果表明，不同种族牙周组织的粘弹性存在差异。由于该系统的阻抗头太大，无法测量种植基牙和磨牙的移动性，因此开发了一种简化的测试仪器，称为T-M测试仪。在齿面施加单频振动，测量加速度响应，然后计算齿体的机械迁移率。探针的齿动换能器采用一组双晶片压电陶瓷片。因此，它体积小，重量轻，适合于口腔检查。通过人工模型验证了换能器的基本特性和测量探头的临床适用性。采用T-M测试仪测定种植体牙周组织与种植周组织粘弹性的差异。结果表明：利用T-M仪可以测量种植体的迁移率。种植体的移动性指数得分低于牙齿。我们应用与T-M测试相同的原理，开发了一种种植体运动（IM）检查器。我们通过人工牙模型和种植体模型验证了其性能。新开发的I-M检测仪具有足够的测量信度，可以客观地估计牙科诊所种植体的运动情况。

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.