[An experimental study of the measuring system of the mean film thickness of white silicone through image analysis].

Clinically, the fitness test of a denture base employing white silicone has been widely used, and there are several methods for assessing the results. However, none of the conventional methods of assessment are completely objective or quantitative. For solving these problems, a new system has been developed for measuring the mean film thickness of white silicone based on image analyzing. There are several factors that affect the results of the fitness test of the denture base, such as the shape of the denture, the condition of the mucosa within denture bearing area, bite force and the state of occlusal contact. Then, using the new system, these factors were examined for clinical application of the mean film thickness of white silicone. The experiments are composed of three stages. In the first stage, the white silicone was pressurized between two of tablets involved in three types, with a pressurizer. These data resulted in a regression equation applying the rheological equation. In the second stage, pressurizing tests were performed on the models of jaw mucosa with uniform compressibility. The models were categorized into three types according to their compressibility. A result was the more compressible the models of jaw mucosa are, the thicker the white silicone film is. In the third stage, the compressibilities were mixed in the models of jaw mucosa. In the pressurizing test, the compressing dies were modeled on the denture base. Five loading points were established on the surface. Correlation between data obtained from the results of the pressurizing test at each loading point was investigated. The results from these experiments were as follows. 1. The regression equation was established from the compressing test of white silicone between tablets of rigid type. H = 0.236 (r1r2/square root of P) -0.0008 R = 0.977 H: mean film thickness of white silicone R: coefficient of correlation P: loading volume r1: 1/2 of the major side of the each tablet r2: 1/2 of the minor side of the each tablet Units are expressed in the C. G. S system. The film thickness was more highly correlated with the distance to the open system of each tablet than the area.