Introduction:

The use of additive manufacturing and environmentally friendly post-treatment processes should enable better and faster supply of dental products and improved occupational safety and environmental compatibility in their manufacture in the future. Until now, the geometrically complex, individual framework structures for dental prostheses have been manufactured from a cobalt-chromium alloy (Co-28Cr-6Mo) in dental laboratories using a complex model casting process with a high proportion of manual work.

A new process chain using metal binder jetting (MBJ), in which a liquid binder is selectively applied to powder particles and thus builds them up layer by layer to form a filigree component, is intended to reduce manual work steps during shaping. The subsequent acid-free finishing with plasma electrolytic polishing (PeP) offers the opportunity to reduce environmental and health impacts. The main issues of the project will be the development of software solutions for distortion and shrinkage compensation during sintering of the structures and the development of a parameter window for the PeP of Co-28Cr-6Mo as an environmentally friendly post-processing strategy. The interaction of material, design, additive manufacturing and post-processing will be considered holistically.

Aim:

The aim of the ProDentAM research project is to develop a process chain consisting of additive manufacturing, specifically metal binder jetting, and plasma electrolytic polishing for the production of metallic framework structures for dental prostheses. The aim is to reduce manual work steps and the environmental and health impact of manufacturing these structures.

Methodology:

At the outset, an orientation model of the clinical situation is simulated and specific requirements for production and production limits are defined. What means, methods, surveys and technologies will be used to achieve this? For the MBJ process, the Co-28Cr-6Mo powder will be extensively characterized and parameters optimized for its processing. In particular, geometrical accuracy, sin-ter density and mechanical stability are considered. In order to control these specifically, a simulation method for distortion compensation of the thin-walled, complex structures is developed and the prediction accuracy is tested iteratively.  For the final process step, post-treatment, an electrolyte adapted to the material system and the associated post-processing strategy are being developed. This includes, among other things, the removal rate, the removal at edges, as well as pick-up points and is also tested iteratively and, if necessary, developed with other processes to form a complete process chain.

Potential, dissemination, transferability:

A successful project leads to a new process chain for the production of metallic framework structures for dental prostheses. This includes a parameter set, as well as a removal strategy for additively manufactured, individualized structures and a post-processing strategy using PeP. The application of this process chain, based on the 590,000 clasp prostheses manufactured annually (as of 2020), would generate a new sector of this industry even if only a small market share is covered (5% in the 1st year, 20% after 3 years). It is also possible to transfer the new process chain to the manufacture of orthodontic appliances and components for other forms of removable dentures. The extension of the process chain to other material systems such as titanium alloys can be applied in other industries such as aerospace.​