Abstract
A shape of denture base is uncertain, and has a curved surface. So, some methods were developed and applied for measuring its area. The method of measuring the denture wearing area have been applicating by some methods. In practice, the method of converting the spray film of vinyl chloride into its weight, the method of converting corroded adapted metal film into its illuminating quantity, and the method of measuring adapted film or paper by planimeter, were reported. The usefulness of them are under consideration, they have both merit and demerit. Among other methods, the method of using planimeter are said to use easy, and often applied. But we are anxious about correctness of measurement.
Now we think to improve these defects, so we have developed the method of measuring denture wearing area, which system is made up of micro-computer, X-Y plotter, and digitizer for planimeter. An outline of this system, the figure to measure is made input to the X-Y axis of cordinates as n-polygon, which is calculated by a method of calculation for the area of npolygon, and is made output to computer display and X-Y plotter.
After examinating these soft and hard wear, we have come to a conclusion that was reliable and useful method to measure area. And then, the method to apply micro-computer obtains an effective number of six figures, but the method to apply planimeter obtains an effective number of three figures. And after measured, there is a merit, which the calculated data are printed out by micro-computer. In the correctness of measurement, the method to use micro-computer is superior to using planimeter in 0.21%.
In the near future, we shall develop this program, and make the system to calculate section property, that is, geometrical moment of inertia and section of modulus.
