Evaluation of a Complete Denture Try-in Method Applying Rapid Prototyping

Objectives: The conventional method of fabricating complete dentures has many problems. To solve these problems, we have applied CAD/CAM technology for complete denture fabrication. Thus far, however, on the use of CAD/CAM technology, we cannot discuss the arrangement of the anterior teeth with patients at the try-in appointment. The purpose of this study was to evaluate a new try-in method applying the Rapid Prototyping (RP) and the conventional method using wax dentures. Methods: Four edentulous patients under maintenance control and eight prosthodontists were enrolled in this study at the University Hospital of Dentistry, Tokyo Medical and Dental University. For each patient, wax dentures were made according to the conventional method. A cone beam CT scanned the wax dentures. CT images were imported into a workstation and translated into 3D images. We made the following seven 3D images of dentures using 3D CAD software; one denture of the same shape of wax dentures, two dentures that changed the size of artificial teeth, two dentures that changed lip support, and two dentures that changed the position of occlusal plane. According to these 3D images of the dentures, a RP machine fabricated seven trial dentures for each patient. Two prosthodontists had try-in for one patient using the conventional method and the RP method. Furthermore, prosthodontists rated their satisfaction level of the two methods on VAS questionnaires. Ratings of expected satisfaction with each conventional and new method were compared using Wilcoxon signed-rank test. Results: Rating of aesthetics with the conventional method was significantly higher than those of the RP method (p<0.05). Rating of chair time and general satisfaction with the RP method were significantly higher than the conventional method (p<0.05). Conclusion: These results suggest that the new try-in method applying RP is very promising.