Queiruga for your assistance in developing the measurement protocol and for providing training on GeoMagic software. Thank you to Kyle Bennett for his technical support in milling the surgical guides. Thank you to my co-residents for your help and sharing practical suggestions throughout the years of my study. I am also grateful to all the faculty, staff and dental assistants for their support and assistance.

The purpose of this research was to compare the accuracy of threedimensionally (3D) printed post and core fabricated with two different materials: reinforced wax and castable resin. Materials and methods:Fifteen extracted single root central incisors were selected. Root canal treatment and tooth preparation for crown were performed on all teeth. Eleven millimeters post space was created with standardized prefabricated fiber post drill. Polyvinylsiloxane impression material was used for root canal impressions. Each impression was then 3D scanned using an extraoral scanner and cast posts and cores were designed using 3Shape software. The digitally designed post and cores were 3D printed with two different materials: castable wax resin and castable resin. The castable resin patterns were scanned before and after complete polymerization. The wax patterns were also scanned. Digital volumetric measurement using Geomagic® Control X™ software was performed to determine accuracy. Results: The printed post and core had reduced volume (16.09 ± 3.839 mm 3 ) compared to the digital design (17.828 ± 3.904, p < 0.05). Before complete polymerization, the accuracy of 3D printed resin pattern (16.464 ± 3.017) was found to be superior to post and core printed with wax (16.193 ± 3.018, p < 0.05). However, no volume difference was found between completely polymerized resin (16.09 ± 3.839) and wax (16.044 ± 3.834, p = 1). Conclusion: 3D printed post and core showed significant volume shrinkage from the digital files used to create them. However, different materials had no effect on the accuracy of 3D printed post and core. K E Y W O R D S3D printing, accuracy of post and core, customized post and core, post and core 540

Queiruga for your assistance in developing the measurement protocol and for providing training on GeoMagic software. Thank you to Kyle Bennett for his technical support in milling the surgical guides. Thank you to my co-residents for your help and sharing practical suggestions throughout the years of my study. I am also grateful to all the faculty, staff and dental assistants for their support and assistance.