[Local compressibility of denture foundation--evaluation of denture foundation in relation to impression pressure]

The viscoelastic character of the denture foundation is different in each individual or site. The character of the mucosa and the appropriate impression procedure should be examined. However, few investigations concerning the relation between the compressibility of the denture foundation and the impression pressure have been reported. The purpose of this study was to discuss the objective evaluation of the denture foundation in relation to the impression pressure. In this report, the local compressibility of the denture foundation of 20 upper edentulous patients was measured with the 20 MHz B-Mode ultrasonic diagnostic equipment. The Compressible Index was defined to analyze the compressibility of the denture foundation quantitatively as against the impression pressure. The main results were as follows: 1. The compressible amount of the denture foundation against 100 gw/cm2 pressurization was an average of 0.32-0.61 mm. 2. The compressible rate of the denture foundation against 100 gw/cm2 pressurization was an average of 13.5-20.7%. 3. The Compressible Index was confirmed to represent the compressibility of the denture foundation accurately as against the impression pressure. 4. It was suggested that the Compressible Index was useful for the clinical simple evaluation of the denture foundation.