Generation of functional Cerec 3D occlusal surfaces: a comparison of two production methods relevant in practice.

The introduction of the Cerec 3D software (R 1500) promised the generation of functional occlusion points and proximal contacts on the basis of a 3-dimensional virtual model on the screen. The objective of this in vitro study was to check this claim in the simulated chairside production of a single tooth restoration. Furthermore, the differences both in conventional finishing and in ceramic glazing were to be determined. For the operator, the latter should simplify or shorten the intraoral finishing and polishing of the occlusal surface, or make it superfluous. To check the suitability of the two methods, these were compared with regard to their quality and the time required to perform them. Ten cavities on articulated models, representing real clinical cases, were each provided with two restorations. One was produced with the glazing method (group A), the other conventionally (group B). The Cerec 3D software, version R 1500, was used for designing the restoration. The restorations made from Vita Mark II ceramic blocks were finished with fine diamond instruments and polished with Sof-Lex disks when using the conventional method. In the alternative method, finishing was practically replaced by glazing the surface. The restorations were evaluated in the articulator, considering both the vertical relation at the incisal pin as well as the accurate position of the contact points. The study showed that functional rehabilitation was possible and no significant qualitative differences occurred in the methods. In this in vitro study, it was found that the glazing method reduced the time required by the operator by around 20% and indicates an improvement in quality. The results of this study promise simplification when the glazing method is used clinically.