Design of 3D-printed macro-models for undergraduates' preclinical practice of endodontic access cavities.

INTRODUCTION: Endodontic access cavity is one of the steps most feared by dental students. The objective of the present work was to show the design phases of different realistic macro-models of a lower first molar, showing root canal anatomy and the ideal access cavity. MATERIALS AND METHODS: Virtual models were designed with MeshMixer, MeshLab and Blender from the data collected (X-rays, CBCT and optical impression) and then printed. Two types of printers-FDM (fused deposition modelling) and SLA (stereolithography) printers-were used to obtain different prototypes which led to final models. A satisfaction questionnaire was then sent to students, after manipulation, to assess the relevance of these models. RESULTS: Two final models of a lower first molar with an extended size (x9) were finally printed with an SLA laser printer with a transparent liquid resin. The first model represented the tooth with its optimal endodontic access cavity. The second one was designed to be divided into two parts according to a mesio-distal axis in order to visualise the root canal system. Most students found these macro-models to be effective tools for endodontic training. DISCUSSION: 3D printing is a proven technology which is no exception in dentistry. Some authors have already proposed 3D-printed replicas of teeth for endodontic education. Macro-models have been designed, printed and made available to students during preclinical courses before and during training. CONCLUSION: These educational macro-models should strengthen the knowledge and skills of students to improve their clinical and future practice within the dental office.