Three-dimensional printing offers possibilities for the development of new models in endodontics. Numerous studies have used 3D-printed teeth; however, protocols for the standardization of studies still need to be developed. Another problem with 3D-printed teeth is the different areas of literature requested to understand the processes. This review aims to gather evidence about 3D-printed teeth on the following aspects: (1) why they are advantageous; (2) how they are manufactured; (3) problems they present; and (4) future research topics. Natural teeth are still the standard practice in ex vivo studies and pre-clinical courses, but they have several drawbacks. Printed teeth may overcome all limitations of natural teeth. Printing technology relies on 3D data and post-processing tools to form a 3D model, ultimately generating a prototype using 3D printers. The major concerns with 3D-printed teeth are the resin hardness and printing accuracy of the canal anatomy. Guidance is presented for future studies to solve the problems of 3D-printed teeth and develop well-established protocols, for the standardization of methods to be achieved. In the future, 3D-printed teeth have the possibility to become the gold standard in ex vivo studies and endodontic training.

Polyetheretherketone is a high-performance thermoplastic polymer that can be used in 3D printing by fused deposition modeling, and is a promising material for dental applications. Some printing parameters are sensitive and can influence the properties of the printed object. Thus, this work aims to evaluate the influence of the print layer thickness on the surface roughness of polyetheretherketone before and after polishing and to verify the effectiveness of the polishing method used, as well as to compare it with the results obtained using polymethyl methacrylate as the control group. Specimens with different impression layer thicknesses were printed with polyetheretherketone (Group A—0.1 mm and Group B—0.3 mm). Additionally, a control group with polymethyl methacrylate specimens was milled. Roughness evaluation was conducted using a contact profilometer after the specimens had been printed (before polishing). Then, silicon carbide sandpaper was used to polish the surface, and the roughness was reassessed. Differences were observed between specimens regarding the print layer thickness and the roughness, with the 0.3 mm layer thickness showing the lowest roughness values. The results of this pilot study suggest that the surface roughness of fused deposition modeling printed polyetheretherketone is influenced by print layer thickness, with the lowest roughness seen at a thickness of 0.3 mm.

This study aimed to describe a support material removal protocol (SMRP) from inside the root canals of three-dimensional printed teeth (3DPT) obtained by the microcomputed tomography (microCT) of a natural tooth (NT), evaluate its effectiveness by comparing the 3DPT to NT in terms of internal anatomy and behaviour toward endodontic preparation, and evaluate if 3DPT are adequate to assess the differences between two preparation systems. After the SMRP, twenty 3DPT printed by PolyJet™ were microCT scanned before preparation and thereafter randomly assigned into two groups (n = 10). One group and NT were prepared using ProTaper Gold^® (PTG), and the other group with Endogal^® (ENDG). MicroCT scans were carried out after preparation, and the volume increase, volume of dentin removed, centroids, transportation, and unprepared areas were compared. For the parameters evaluated, no significant differences were found between the 3DPT and NT before and after preparation (p > 0.05), and no significant differences were found between the 3DPT PTG group and the 3DPT ENDG group (p > 0.05). It can be concluded that the SMRP described is effective in removing the support material SUP706B™. PolyJet™ is adequate for printing 3DPT. Furthermore, 3DPT printed with high-temperature RGD525™ have similar behaviour during endodontic preparation with PTG as the NT, and 3DPT can be used to compare two preparation systems.

This study aimed to evaluate by microCT the preparation of the artificial teeth (ATs), TrueTooth^®, versus natural teeth (NTs): (1) the time and number of pecking movements needed for preparation; (2) the root canal volume increase; (3) if the pulp-colored medium has any effect on the 3D analysis. Material and Methods: Artificial and natural maxillary molars were used. Fourteen AT distobuccal canals and fourteen NT buccal canals were used for the first and second aim and fourteen AT mesiobuccal canals for the third aim. Results: No statistically significant differences were observed regarding the time and number of pecking movements (p > 0.05); for the root canal volume increase, a statistically significant difference was observed (p < 0.05) with a higher mean value for NTs; however, in the group of ATs, there was a volume decrease in three cases. The AT mesiobuccal root canal mean volume increase was also negative. Conclusions: There are no differences between the time and number of pecking movements between NTs and ATs, so TrueTooth^® can potentially be used in endodontic training. The volume increase between ATs and NTs was higher in NTs. However, some samples showed negative values, also seen in the AT mesiobuccal canal, confirming that the pulp-colored medium has an effect on the 3D analysis.