Digital versus conventional workflow in oral rehabilitations : current status

Abstract

In recent years, computer-aided design and computer-aided manufacturing (CAD-CAM) technology has developed along with its applications in dentistry, including several new techniques that are used in oral rehabilitation applications. These techniques usually differ from conventional analog techniques regarding the way in which impressions are obtained (e.g., conventional impressions vs. intraoral scanning) or the way restorations are designed and produced (e.g., conventional waxing and casting vs. CAD-CAM). The general advantages that digital workflow involving CAD-CAM has over conventional workflow include faster treatment times, shorter appointments, reduced patient discomfort, no need to use plaster models and better predictability. Another key feature of digital workflow is the ability to merge and superimpose three-dimensional (3D) meshes from different imaging examinations to create a virtual patient, which enhances virtual treatment planning and communication with patients. The general disadvantages of digital workflow that have been described include purchasing and managing costs, as well as a learning curve. Nevertheless, it is also important to understand differences in quantitative outcomes such as trueness and precision between digital and conventional workflows. One of the most commonly investigated quantitative comparisons in digital dentistry is between conventional impressions and intraoral scans. In comparison to conventional impressions, intraoral scanning (IOS) has been considered to be more accurate in regard to the outcomes of resulting CAD-CAM crowns and short-span fixed partial dentures. Several articles have found marginal gap values lower than 60 μm for CAD-CAM dental crowns produced using IOS, whereas gap values up to 183 μm were found for crowns produced using conventional impressions. One finding that is found across multiple studies is that ensuring the accuracy of intraoral scans of long-span and completely edentulous arches it is still challenging.