Precision of Digital Prosthodontic Planning for Oral Rehabilitation

Abstract

Aims: Recently, digital wax-up is proposed as a tool to aid prosthodontic planning. Accuracy is a requirement of the diagnostic wax-up in order for its information to be transferrable clinically.The purpose of this study is to evaluate the precision of digital prosthodontic planning in the form of digital wax-up. Study Design: Comparative study. Place and Duration of Study: Oral Health Centre of Western Australia and School of Computer Science and Software Engineering, University of Western Australia, from June 2012 to December 2013. Methodology: Twenty-five dental arch models of 15 patients were collected. The models were duplicated twice to allow for the execution of conventional wax-up and digital wax-up. The conventional wax-up involved tooth modification with inlay wax. The digital wax-up was based on fitting average tooth forms on virtual pre-treatment models. For the analysis, the conventional wax-up models were converted to digital models. All the wax-up models were segmented to yield soft tissue and tooth-gingiva models. With the aid of the 3D image registration process, the segmented models were superimposed on the pre-treatment models to evaluate the accuracy of fit. Further, the gingival margin discrepancies of each wax-up protocol were evaluated. Results: The image registration process revealed less discrepancies for the digital wax-up (soft tissue = 0.11mm, tooth-gingiva junction = 0.11mm) than the conventional wax-up (soft tissue = 0.18mm, tooth-gingiva junction = 0.20mm). Similarly, the gingival margin discrepancies were less for the digital wax-up. However, the patterns of discrepancies were similar for the two wax-up protocols. Conclusion: In terms of accuracy and transferability, the digital wax-up is comparable to the conventional wax-up.