Rubber Hardness Discrimination and Associated Bite Force in Osseointegrated Implant Patients

为阐明牙周膜的功能作用，对20名正常牙齿受试者和6名种植者的牙间橡胶硬度进行了检测。一个钛种植体[Branemark系统]在正畸治疗后被植入上切牙位置。制备了五种不同硬度的橡胶试件进行试验。每片分别放置在上颌种植门牙和天然门牙的位置。受试者被要求评估与参考试件相比，试件的手感是否更硬、更软或硬度相似。在识别过程中，用应变片电测咬合力。正常受试者左侧错误率为25.2[-+]7.5%，右侧错误率为28.2[-+]5.4%。在种植患者中，自然部位的误差率为23.3[-+]5.0%，种植体部位的误差率为28.0[-+]8.7%。受试者之间和被检查地点之间的错误率没有观察到任何差异。在种植体患者中，橡胶硬度在自然部位和种植体部位误差分布的中位数没有差异(自然：51.1[-+]3.2°，种植体：50.2[-+]2.5°)。然而，患者的咬合力显著高于正常牙齿受试者(p&lt；0.001)，个别患者自然部位的咬合力与种植部位的咬合力没有差异。这些结果提示正畸治疗对种植体患者的牙周膜有一定的影响，通过控制咬合力，牙周膜在橡胶硬度辨别中可能起到补偿作用。

To clarify the functional role of the periodontal membrane, interdental discrimination ability of rubber hardness was examined in 20 normal dentate subjects and 6 implant patients with cleft palate. One titanium implant [Branemark system] was inserted into the upper incisor site after orthodontic treatment. Five different test pieces of rubber hardness were prepared for the experiment. Each piece was placed at the site of upper implant incisor and natural incisor. The subjects were asked to assess whether a test piece was felt harder, softer or similar in hardness compared with a reference test piece. Bite forces were electrically measured with strain gauge during the discrimination. The error rate of the normal dentate subjects was 25.2【minus-plus】7.5% (mean 【minus-plus】 SD) on the left site, and 28.2【minus-plus】5.4% on the right. In the implant patients, the error rats were 23.3【minus-plus】5.0% in the natural site, and 28.0【minus-plus】8.7% in the implant site. Any differences in the error rates were not observed between subjects, and between sites examined. In the implant patients, the median of error distribution for rubber hardness in the natural site was not different from implant site (natural : 51.1【minus-plus】3.2 deg., implant : 50.2【minus-plus】2.5 deg.). However, bite forces of the patients were significantly higher than that of normal dentate subjects (p<0.001), and bite forces in the natural site were not different from those in the implant site in individual patients. These results suggested that the periodontal membrane of these implant patients may be affected by orthodontic treatment, and that, controlling bite forces, periodontal membrane in the lower teeth may play compensation in rubber hardness discrimination.