Material characterization and defect detection of additively manufactured ceramic teeth using non-destructive techniques

Abstract

In recent years, additive manufacturing (or) 3-Dimensional (3D) printing is applied to denture materials widely. However, there is no proper technique or standard for testing the material properties such as Young's modulus and Poisson's ratio that are directly related to the strength of denture materials. This research focuses on the use of laser ultrasound technique, ultrasonic microscopy, and ultrasonic C-scanning imaging system to explore the material properties and acoustic parameters of human teeth and additive manufactured teeth. In addition, defect detection is performed on the additively manufactured teeth to provide the relevant information to help the dentists. Firstly, we used ultrasonic microscopy to obtain the surface wave velocity of the denture material and obtained the elastic coefficient of the material through the principle of wave propagation. Secondly, the laser ultrasound technique was performed on denture material in a non-destructive way, and the inverse calculation procedure was applied to obtain the elastic coefficient of the denture material. Finally, the elastic coefficient was obtained from the three-point bending test, and the correctness of the back-calculation results of ultrasonic microscopy and the laser ultrasound was verified. Results showed that the elastic coefficient obtained by the laser ultrasonic combined with the inverse calculation was comparable with the three-point bending test, with the error value within 5%. The comparison error between the ultrasonic microscopy and the three-point bending test was within 15%. Besides, the ultrasonic C-scanning system can detect the defects with an accuracy of less than 0.2 mm. Therefore, this research has successfully measured the material properties, acoustic parameters, and defect detection of dentures through non-destructive ultrasonic testing. It demonstrates considerable potential in dental medical measurement and can provide effective methods for the testing and manufacturing of denture materials.