Development of a Wear Testing Machine for Dental Crown Application

Abstract

A three axes wear testing machine for a dental crown was developed for human tooth application. There were two main sections of the controllers: the application of an AC servomotor (Z-axis) for creating and controlling the force which is used in testing and the application of a step motor (X-axis and Y-axis) for creating and controlling the motion. This study aimed to compare the ability of the controlling force of the AC servomotor on two different surfaces—a smooth fl at surface and a dental crown surface. Three testing cases were considered at frequencies of 0.5, 0.75, and 1 Hz in a range of motion of 1 mm: 1) simulating the force of chewing (0–60 N) and the motion of a circular process, 2) simulating a constant force (60 N) of one way movement in a circular process and 3) simulating a constant force (60 N) of the reciprocating movement in a circular process. The machine was tested using a dental crown, which was made of zirconia, by simulating the force, the motion and the various conditions of the teeth in the oral cavity. The force which occurred in all three axes was measured by the load cell. According to the experiment, the AC servomotor was able to control the force exerted on two different surfaces with nearly similar results. The average force errors on the smooth surface and the dental crown surface were 13.70 and 13.82%, respectively. The root mean square errors of the smooth surface and the dental crown surface were 17.47 and 16.99, respectively.