Abstract: A masticatory efficiency measuring apparatus of the present invention includes a tank (3) that contains a stirring liquid to be supplied to a measuring container (2), a heater for heating the stirring liquid in the tank (3), a stirring device for stirring chewed food pieces in the stirring liquid with the measuring container (2) containing the chewed food pieces and the stirring liquid, a concentration meter (5) for measuring the concentration of a food component eluted into the stirring liquid from surfaces of the chewed food pieces, and a control device. The control device controls operations of the heater, stirring device and concentration meter (5), and determines the masticatory efficiency evaluating value based on the measurement result of the concentration meter (5).

Abstract: Abrasive grains are produced by gluing an abrasive powder to an elastic porous carrier. A number of abrasive grains are mixed with an abrasive liquid, and are then sprayed to the surface of a work at an oblique angle thereto to impact it while allowing the abrasive grains to slide on the surface of a work to finish the surface of the work. Over the distance of travel over which the abrasive grains slide, the surface of the work are ground. The elasticity of the carrier allows the abrasive grains to deform matching the contour of the work. By spraying a number of abrasive grains on the work, grinding action is performed in consideration of the contour even if the work is a complicatedly contoured surface such as a dental prosthesis while a polishing effect is obtained at the same time.

Abstract: A ceramic powder having a uniform particle diameter of 50 .mu.m or smaller is used as a dental ceramic powder to produce a high-precision and compact artificial tooth. The ceramic powder fired assures a non-porous and compact structure of the artificial tooth. In a manufacturing method for the artificial tooth, the cream of ceramic powder is poured into a core, the core with the ceramic cream loaded is frozen to shape, thawed, dried and then fired in a furnace. To assure even more compact structure, the cream is compacted and hardened prior to freezing. Pressure is efficiently applied in the compaction and hardening process.