Innovative Digital Protocol for Standardized Endocrown Preparation of Natural Bicuspids

Abstract

Purpose: To establish and verify new digital technique to standardize endocrown preparations using CAD/CAM. Material and Methods: Ten recently extracted intact maxillary premolars were selected in this study. All teeth received standardized endodontic treatment. A standard 3D virtual designed cavity preparation was selected with specific dimensions. This preparation was sent to CAD software as STL file. All teeth samples were held within milling machine using special design attachment. All teeth were then scanned using trios 3. The scanned teeth were checked for trueness using 3D comparing engineering software by superimposition of the virtual model STL file as a control model to each STL file of the ten scanned teeth. Results: The total similarities and differences between 3D designed cavity preparations from Rhinoceros software were compared with the STL files of scanned specimens. The mean difference between the samples and the reference was 0.093 millimeters. Conclusion: 1) The mean trueness of all teeth samples was quantitively within the acceptable range (+100 ___ -100 micron), considering clinically relevant threshold in literature, 2) Qualitatively, the pulpal floor showed the most uneven deviation pattern.