Rubber Hardness Discrimination and Associated Bite Force in Osseointegrated Implant Patients

为明确牙周膜的功能作用，对20例正常牙体和6例腭裂种植体患者进行了橡胶硬度的牙间辨别能力测定。正畸治疗后，将一颗钛种植体（Branemark系统）植入上切牙部位。为实验准备了5种不同的橡胶硬度试样。每个片放置在上种植切牙和自然切牙的位置。受试者被要求评估与参考测试片相比，测试片的硬度是否更硬、更软或相似。在判别过程中，用应变计电测咬合力。正常齿状体受试者的左侧误差率为25.2【负正】7.5%（平均【负正】SD），右侧误差率为28.2【负正】5.4%。在种植体患者中，自然部位的误差为23.3【负正】5.0%，种植体部位的误差为28.0【负正】8.7%。在被试之间和被测地点之间，没有观察到错误率的任何差异。在种植体患者中，天然部位橡胶硬度的误差分布中位数与种植体部位没有差异（天然部位：51.1【负加】3.2度，种植体：50.2【负加】2.5度）。然而，患者的咬合力明显高于正常牙齿受试者（p<0.001），并且个体患者自然部位的咬合力与种植部位的咬合力没有差异。结果表明，正畸治疗可能会影响种植患者的牙周膜，下牙的牙周膜在控制咬合力的情况下对橡胶硬度的区分起到补偿作用。

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.