Evaluation of custom posts and cores fabricated by two digital technologies in core and post space dimensions

Abstract Objectives To evaluate the adaptability between posts and post spaces and the rationality of cores fabricated by two digital custom posts and cores processes. Materials and methods Titanium posts and cores were fabricated by digital scanning impression technology or digital scanning wax-pattern technology on tooth defect molds of incisors, premolars, and molars, with traditional lost-wax casts of these teeth as the controls. Micro-CT and a laboratory scanner were used to determine intervals between post wall and root canal wall of the root apex, middle, and cervix of each sample in cross-, sagittal, and coronal sections; intervals between the end of post and tooth; diameters of cervical, middle, and incisal part at cross-, sagittal, and coronal sections of each sample, as well as shoulder widths. Results Three fabrication processes showed significant differences in intervals between post-and-core prostheses and root canal wall, diameters of all parts of cores, and shoulder widths. Scanning impression showed significant advantages in the main part of posts and cores in incisors and premolars, while the scanning wax-pattern process showed obvious inferiorities in premolars and molars. As to core spatial size, values of measured sites in the scanning impression process were closer to the standard than those of the traditional process, while differences between the measured value of the scanning wax-pattern process were much more obvious than in the traditional process. Conclusion The digital custom posts and cores employed scanning impression improved rationality and precision of post-and-core dimensions compared with the two other processes. Clinical relevance Fabrication using digital design and processing for custom posts and cores has better precision and adaptability.