Use of 3-dimensional-Printed Guide in Hemisection and Autotransplantation of a Fusion Tooth: A Case Report.

Three-dimensional (3D)-printed guides have been used in endodontics to prepare a conservative access, locate calcified or missing canals, and perform precisive osteotomy in apicoectomy. Here, we present the treatment of a fusion tooth by combining 3D printing technology and endodontic intervention in a 10-year-old patient. The bifid crown of a maxillary right lateral incisor #7 had caused esthetic concerns and malocclusion. Clinical and radiographic examinations showed that #7 is fused with a supernumerary tooth with 2 independent root canals. The fusion involved the entire crown and the coronal and middle roots. Because of financial constraints, a multidisciplinary approach involving endodontic, orthodontic, and prosthodontic treatment was excluded. We hemisectioned the tooth intraorally with a 3D-printed guide, extracted the supernumerary tooth, and transplanted tooth #7 to a position with improved esthetics and occlusion. A 3D-printed tooth replica was used to prepare the recipient site for autotransplantation. At the 6-month follow-up, tooth #7 was diagnosed with pulp necrosis and asymptomatic apical periodontitis. Root canal treatment of tooth #7 was completed, and osseous healing was observed 8 months later. The patient had no clinical symptoms and was satisfied with the outcome 14 months after hemisection and transplantation. The open space between teeth #7 and #8 was closed without orthodontic treatment. We present an alternative option to treat a fusion tooth in young patients who do not opt for other treatment options because of their stage of development or for socio-economic reasons. Techniques in modern endodontics, such as cone-beam computed tomographic imaging and 3D printing, should be adapted when it is beneficial to patients.