A recent scientific study at the University of Washington proved a key feature of the Z4. Using the milling and grinding machine, dental professionals can drill screw-access channels for hybrid implant restorations, e.g. screw-retained crowns, into regular ceramic blocks with no significant difference in flexural strength compared to factory-pre-drilled ‘meso’ blocks, which are significantly more expensive, and for which the nesting process is more challenging.
The study compared screw-access channels that were prefabricated under factory settings and channels milled in a Z4 milling and grinding machine from vhf. For this, a variety of ceramic CAD/CAM materials from different manufacturers was evaluated. The study ultimately proved that there was no significant difference in flexural strength of ‘meso’ blocks, compared with Z4-drilled blocks. Therefore, processing standard blocks with the Z4 means less cost for material and less material inventory necessary. The authors of the study were Jack M. Keesler, DDS, MSD, under guidance of the renowned Professor John A. Sorensen, DMD, PhD, FACP. This study was for Dr. Keesler’s University of Washington 2019 Master’s Thesis.
The CEO of vhf Inc., Nicolas Rohde, PhD, appreciates the study results: “The study results are of paramount importance for users of milling machines and a convincing argument for those who are thinking of purchasing a Z4. Our customers can conveniently finish perfect restorations at lower cost by drilling screw-access channels in highest quality.”
The Z4 is a four-axis, high precision milling and grinding machine with an integrated compressor and PC that requires no additives for the water-cooling system. Developed for same-day dentistry, it enables patients to receive high-quality restorations much faster. The block material is fixed without tools and can therefore be exchanged in seconds. For the study, two fine-grained diamond radius tools from vhf were used for grinding the channels.