Study of Denture Foundation with B-mode Ultrasonic Equipment - Development Measuring System for Occlusal Load and Thickness of Denture Foundation -

本研究的目的是开发图像处理系统，它可以测量义齿基托的厚度和咬合力。使用该系统，我们研究了义齿基托的可压缩性并确定特定区域的厚度减轻量。在本报告中，使用20 MHz B型超声诊断设备测量了60名全口义齿佩戴者在非咬合负荷和最大咬合力下的粘膜厚度。另外，对15例全口义齿修复后，分别在切牙乳头、腭隆凸和腭正中缝处减轻0.25、0.50、0.75、1.00mm的情况下，用同样的方法测量了粘膜厚度。该系统可测量义齿基托厚度，测量精度为0.1mm.在最大咬合力作用下，粘膜厚度平均减少约0.3mm.在最大咬合力作用下，下颌骨粘膜厚度的下降速率大于上颌.从减轻手术后粘膜厚度的减少情况来看，重度腭突需要减轻0.50mm，中度腭突需要减轻0.20-0.50mm。即使在不存在腭隆凸的情况下，在切牙乳头和腭正中缝区域厚度减轻约0.25 mm也是理想的。

The purpose of this study was to develop the image processing system, which allows to measure the thickness of the denture foundation and the occlusal force. Using this system, we investigated the compressibility of the denture foundation and to determine the amount of relief in thickness over the specific area.In this report, the mucosal thickness of 60 complete denture wearers were measured with 20 MHz B-Mode Ultrasonic Diagnostic Equipment, under both non occlusal load and maximum occlusal force. Moreover, the mucosal thickness of 15 complete denture wearers whose dentures were relieved by 0.25, 0.50, 0.75, 1.00mm over the areas of incisive papilla, torus palatinus and median palatine suture were also measured by the same manner.The main results were as follows :1. The thickness of the denture foundation could be measured at the accuracy of 0.1mm in the system.2. Decrease in the mucosal thickness under maximum occlusal force was about 0.3mm in averages.3. Decreasing rate in the mucosal thickness under maximum occlsal force was greater in a mandible than in a maxilla.4. Judging from the decrease in the mucosal thickness by relief procedures, it was found that 0.50mm relief in thickness was necessary in a case of severe torus palatinus and 0.20-0.50mm relief in a moderate one.5. Even in a case without the existence of torus palatinus, about 0.25mm relief in thickness was desirable over the incisive papilla and median palatine suture areas.