Non-destructive evaluations of 3D printed ceramic teeth: Young's modulus and defect detections

Additive manufacturing (AM) or 3-Dimensional (3D) printing has become a promising manufacturing technique in architecture, aerospace, automotive and dental medicine industries. However, additively manufactured parts need to demonstrate their stable mechanical properties. In this study, 3D printed dentures were made by two different sintering temperature to explore the changes in material properties. The Young's modulus of the 3D printed dentures were calculated and compared with CNC produced denture. Further, artificial defects were created on 3D printed dentures and scanned to identify the defects using ultrasonic technique (UT). The pulse exciter is used to excite the ultrasonic penetration denture and receive the echo to determine the location and size of the defect. Besides, the same artificial defects were scanned by Computer tomography (CT) to compare with Ultrasonic technique. From the obtained results, the 3D printed all-ceramic denture can achieve the strength of the current all-ceramic denture which is produced from CNC process. The sintering parameters in the 3D printing process can easily affect the material properties as shows the variation in Young's coefficient. The experimental results indicate that the Ultrasonic non-destructive technique showed 0.2 mm accuracy in defect scanning, with minimum error of 2.3%. In addition, the denture information obtained by Ultrasonic C scanning was successfully processed by the software to create a 2D planar tomographic image of the denture. The Ultrasonic C-scan technique can be adopted as an alternative method to identify the defects in ceramic based 3D printed teeth.