Basics of digital prosthetic fabrication

The Ceramill Full Denture System (Amann Girrbach) enables efficient, precise CAD/CAM-supported denture fabrication. With VITA VIONIC Solutions (VITA Zahnfabrik), there is now the right material system for every step of digital production. Thanks to the combination of intelligent manufacturing technology and coordinated materials, laboratories can increase their productivity in prosthetics. With the Ceramill Mind software, VITA denture teeth can be used to create digital setups in more than 300 functional variants. Here, engineer Falko Noack, Head of Application Technology R&D at Amann Girrbach, answers questions about the digital workflow and its advantages.

What do we need to consider in the digital workflow in order to achieve a good end result?

When working digitally, the same principles apply as in the manual process - if the working base does not fit, the final result will also be deficient. The most relevant step is not with the dental technician, but with the dentist or prosthetist. Digital prosthetics require proper functional impressions to produce adequate models and an accurate bite registration.

What options are offered by the Ceramill Mind software for denture setup?

In principle, with VITA denture teeth and the Ceramill Mind software, patient-specific denture settings can be created in more than 300 functional variants. At the start, the software allows individual positioning of each individual tooth. In the posterior region, the virtual alignment is done according to the specifications of digital model analysis. However, the modification of the digitally set up posterior teeth can only be done in conjunction with opposing quadrants, to ensure that ideal occlusion relationships are guaranteed at all times.

What options does the dental technician have for the setup and design of the gingiva?

For VITA VIONIC Solutions, laboratories have a choice between buccal and lingual concepts when designing with Ceramill Mind - depending on the anatomical situation and/or the desired philosophy. In addition, in terms of the occlusal position, the software supports the cross bite, as well as the normal bite. Ceramill Mind offers digital design tools, such as the free-form function of the wizard, for the individual design of the gingival portions.

How is the try-in done with VITA Vionic Solutions and Ceramill FDS?

For the clinical wax try-in, there are tooth and gingiva-coloured VITA VIONIC WAX blanks. The lab can either mill a full-sized wax try-in from a tooth-coloured blank, or produce the base from gingiva-coloured blanks and affix the CAM-modified denture teeth in the milled alveoli. If the wax try-in was in full-size, then the CAM-modification takes place only on completion.

How is the final completion done and what components are needed?

After a successful try-in, the final denture base is milled using Ceramill Motion 2 from a PMMA blank. For this, the VITA VIONIC System offers VITA VIONIC BASE blanks in different gingiva shades. With the VITA VIONIC FRAME prosthetic frame solution, the CAM-supported basal and circular modification of the denture teeth can be “semi-automated,” according to the digital prosthetic design. This ensures a precise fit of the denture teeth to the milled alveoli. Adhesive fixation of the denture teeth in the alveoli of the base is then performed with the VITA VIONIC BOND fixation system.

What are the advantages of digital prostheses with regard to precision and fabrication time?

The factory system settings automatically provide correct occlusion and are very user-friendly. This results in increased precision and reduced time. In particular, the digital tooth setup allows a time savings of up to 60 percent compared to manual installation. By milling the wax or synthetic base, wax contraction or polymerization shrinkage are eliminated as sources of error.

First published in Digital Dentistry 1/2018, OEMUS MEDIA AG, Germany.