# Print and Try Technique: 3D-Printing of Teeth with Complex Anatomy a Novel Endodontic Approach
## 2 Case Description  
### Case 1  
History and physical examination: A 35-year-old healthy female, without any history of dental trauma, was referred to the endodontist for assessment of her upper right maxillary lateral incisor: she presented complaining of pain on the element 12, especially when chewing, lingering for several days. An extraoral examination did not reveal abnormalities. An intraoral examination showed an aberrant coronal anatomy of element 12: the crown was wider mesially, with a slight irregularity of the incisal edge, hence a dens invaginatus was suspected (Figure 1a);The tooth was negative to cold and heat sensitivity testing, percussion and palpation tests were both positives, whereas the adjacent teeth responded normally. Electric pulp testing confirmed pulpal necrosis. There was no swelling in the apical mucosa area. Probing values, in absence of bleeding and suppuration, revealed a healthy periodontal status. Imaging examination and diagnosis: A long cone periapical (LCPA) X-ray (Figure 1b) was taken (X-minD\({}^{\text{TM}}\) Unity, ACTEON@IMAGING, Merignac, France). Dens invaginatus type3a anatomy [35] was confirmed and chronic apical periodontitis was diagnosed, with a radiolucent area on the mesial aspect of the root, laterally to the main canal, where the invagination was communicating with the periodontal ligament through a pseudo-foramen; a large periapical radiolucency surrounded the periapex. A small-FOV CBCT (Orthophos XG 3D, Dentsply Sirona, Charlotte, VA, USA) (Figure 1c-Movie 1) was taken as a supporting examination. The axial slices confirmed that the main root canal, developing from a small distal chamber, was separated from the invagination at all levels; furthermore, it showed that the invagination was limited to the root, not involving the clinical crown of the tooth, the periapical lesion was present both at the main and the pseudo-foramina and that it had perforated both the buccal and the palatal cortical plate. Figure 1: (**a**) Intraaoral examination showed a wide crown of element 1.2, typical anatomy of a dens invaginatus. (**b**) Periapical X-ray showed a mesial invagination separated from the main distal canal (dens invaginatus type3a), with an apical radiolucent area. (**c**) CBCT confirmed these findings. Print and Try technique and treatment planning: The CBCT file was transformed in an STL one. On the STL file the bone structure was previewed with and without the tooth (Figure 2a-d-Movie 2) and tooth dimensions, including the invagination size, were measured (Figure 2e-g). Afterwards alveolar bone with and without the tooth was printed using the 3 DSlicer software and a Formlabs printer (Figure 3a,b); a specific tooth model was obtained through a Meshmixer software and a Stratasys printer (Figure 3c). Figure 2: (**a–d**) An STL of bone structure with and without element 1.2 was produced and (**e–g**) dimensions of element 1.2 were achieved. A clear material was chosen for the single tooth model (VeroClear, Stratasys, Eden Prairie, MI, USA), thus enabling visualization of both the root canal system and the instruments used at the different negotiation stages. Working on the 3D-printed models it was possible to determine the best treatment option which would have comprise of a primary orthograde endodontic treatment for the main canal, immediately followed by a surgical approach to achieve an adequate sealing of the invagination (Figure 3d). On the transparent tooth model, an occlusal distal conservative access cavity was centered on the main canal and then flexible rotary instruments were tried in to negotiate the canal lumen. A flexible irrigation plastic needle was confirmed to reach within 1 to 2 mm from the working length, even in the presence of a significant curvature between the middle and last third of the canal; also, the obturation stage was rehearsed and it was confirmed that a 3D-filling with warm gutta-percha was achievable. Finally, a complete infill of the invagination was practiced in a mock surgery with a putty bioceramic material.