[Effect of addition of calcia on the properties of zirconia investments].

The zirconia investments with calcia were studied of the compressive strength, setting expansion, thermal expansion, total expansion, thermogravitometry, differential thermal analysis on fabrication method, concentration, particle size of zirconia, calcia and mixing liquid. Addition of calcia caused the change from contraction to expansion in setting expansion. The optimum concentration of calcia was determined to be 10 mol% as judged from total expansion, strength and operability.