In this comprehensive review, the current state of the art and recent advances in 3D printing in dentistry are explored. This article provides an overview of the fundamental principles of 3D printing with a focus on vat photopolymerization (VP), the most commonly used technological principle in dental practice, which includes SLA, DLP, and LCD (or mSLA) technologies. The advantages, disadvantages, and shortcomings of these technologies are also discussed. This article delves into the key stages of the dental 3D printing process, from computer-aided design (CAD) to postprocessing, emphasizing the importance of postrinsing and postcuring to ensure the biocompatibility of custom-made medical devices. Legal considerations and regulatory obligations related to the production of custom medical devices through 3D printing are also addressed. This article serves as a valuable resource for dental practitioners, researchers, and health care professionals interested in applying this innovative technology in clinical practice.

Innovations in intraoral scanner (IOS) technology are opening up ever more indications for computer-aided design and manufacturing (CAD-CAM). The manufacturers claim that the latest generations of scanners allow the digitizing of root canal preparations. However, there is a lack of studies evaluating the quality of the optical impressions made for this type of treatment. The purpose of this study was to evaluate the measurement error of 4 IOSs and a laboratory scanner used for the digitizing of root canal preparations and to highlight the effect of the presence or absence of adjacent teeth on the quality of the digital model. Two models: one presenting adjacent teeth, one without adjacent teeth, both presenting a 10 mm deep nominal conical pit mimicking a root canal preparation were fabricated. Each model was scanned 10 times with a laboratory scanner (E3) and 4 intraoral scanners (Primescan, Omnicam, TRIOS 4, and Medit i700). The digital models were then exported as standard tessellation language (STL) files and analyzed to evaluate the mean measurement error of the digitizing of the root preparation at three different depths: 0-3 mm, 3-6 mm, and 6-9 mm. Significant differences were assessed with a 1-way ANOVA test and the pairwise comparison between scanners was done by Tukey's multiple comparison test. Statistical differences were found between scanners (P < 0.05). The mean measurement error ranged from 9.8 ± 0.5 μm with the Medit i700 to 28.2 ± 10 μm with the E3. The E3 and Omnicam scanners were in some cases incapable of digitizing the conical preparation in its entirety. The group Primescan, TRIOS 4, and Medit i700 showed minimally significant differences. The presence of adjacent teeth had a negative effect on the model quality for some scanners, mainly because of the obstruction of the IOS's head. Significant differences were found among the dental scanners used for digitizing root canal preparations. Optical impressions with modern intraoral scanners seem to be an adapted method of registration of root canal preparation for post-and-copings of post-and-cores fabrication.