A comparative study of the accuracy of five CAD-CAM systems

The study aims at comparing the precision of different CAD/CAM systems: original systems built by the same manufacturer as opposed to systems whose components are built by different manufacturers.

We used the same physical cast which was scanned with five different scanners. The design of the PMMA copings was done by the same operator for the five virtual casts. Each coping was milled three times by each milling machine, thus obtaining 75 copings. The internal space was analyzed by scanning the replicas in light body silicone.

The results analyzed the vertical marginal space (VMS) at the preparation limit, the axial internal space (AIS) and the internal occlusal space (IOS). For VMS the best results were obtained for scanner no 5 (S5) and milling machine 3 (M3). For AIS the best results were obtained with S4 and M3 combination. For IOS the best results were obtained with S45 and M3 combination.

According to the results of the study, we are able to confirm the working hypothesis by stating the following conclusions: the quality of the prosthetic elements obtained through CAD/CAM processing differs depending on the CAD/CAM system used and is influenced by each component of every system individually, both the scanner and the milling unit; changing/switching any component of the CAD/CAM system has an impact on the quality of the resulting prosthetic work, but in an unpredictable manner.