Medical Engineering

The manufacture of dental prostheses is characterized by a long tradition of artisanship, which still consists of a multitude of time-consuming and cost-intensive manufacturing processes. For this reason, the market for dental prosthetics in Europe and especially in Germany is undergoing major changes. Additive technologies offer a starting point for a digital process chain for dental applications.

Frameworks (SLM)

Not only the "pressure", but also the additive processes in manufacturing require the integration of upstream and downstream steps: Automated handling of materials and components, cleaning as well as quality control, for example by image processing systems. Process reliability and reproducibility are important criteria in the development of new applications.

Coating and active materials

The institutes of the Fraunhofer Competence Field Additive Manufacturing are researching the connection of additively manufactured implants with special coatings for improved biocompatibility. Different layer systems are applied to laser beam melted titanium implants and tested in vitro with regard to cell growth. Thus, especially suitable coating systems can be developed for the laser beam fused titanium implants.

The integration of active materials such as shape memory alloys in laser beam fused implants is another research topic of the Fraunhofer Competence Field Additive Manufacturing. The active implant adjustment in a large number of friction-locked pressure zones optimizes the pressure force on the bony environment and distributes the load dynamically. The active material composite actively counteracts the loosening of the implant over time and thus avoids the need for further operations.

Structures

The additive manufacturing process of laser beam melting offers a variety of solutions for biomedical technology: Additively manufactured products do not have to take into account the geometric and manufacturing limits of today's serial production and can be perfectly adapted in form and structure to the needs of the patient. Not only artificial joints such as hip, knee, shoulder or spine, but also individual skull and other bone plates or jaw implants can be manufactured in this way.

Laser beam melting allows medical implants, instruments and devices to be individually manufactured from biocompatible materials such as titanium, cobalt-chrome or stainless steel, which otherwise can only be produced with great effort or not at all by other methods. The geometric freedoms of laser beam melting make it possible to manufacture implants and prostheses with the most complex internal and external structures to measure. Computer tomography data, for example, can serve as a starting point.

Reliability of implants

Biomedical materials and implants have to meet the highest demands in terms of reliability and performance. Load-bearing implants, for example, must have sufficient fatigue strength to prevent failure in the patient. Suitable mechanical alternating load tests, which simulate the physiological loads, are usually used for this purpose. In the case of individual implants, which are only manufactured in small quantities, further approaches for quality assurance must be considered in addition to experimental tests. The simulation of the component behavior under consideration of the influence of the manufacturing processes can contribute to the reliability evaluation.

An amputation is always associated with a tragic fate. Serious accidents and life-threatening diseases precede every amputation. Every amputation is associated with a long rehabilitation phase.

In order to provide an amputee with the best possible care, an individual solution is always indicated. However, the integration of highly technical components such as computer-chip-controlled knee joints and myoelectronic controls is only one factor in successful patient care. Other characteristics are usually decisive for patient satisfaction: the prosthesis must fit the body exactly. It should be very light and look good. It is precisely in these points that additive manufacturing can provide significant advantages.

Leg prostheses

When manufacturing prostheses, the shape of the residual limb, weight, size and mobility of the patient as well as the individual walking style must be taken into account. The remaining musculature and the anatomical conditions in the residual limb play a role here. Today, this individual adaptation is achieved almost exclusively by using modular prostheses. The focus here is on the function of the prosthesis. Another important point is often forgotten: The appearance of today's modular prostheses is not appropriate for an object that has to be worn every day - this is also the opinion of those affected. Producing a suitable, well-functioning and aesthetically appropriate leg prosthesis requires a lot of manual work, anatomical knowledge and manual skills, but also the appropriate manufacturing process.

Hand orthoses

In contrast to prostheses that replace limbs, orthoses support parts of the body with limited functionality. The reasons for this are just as varied as the individually applied solutions: Fixations, correction of malposition’s, paralysis or muscular dystrophy - to name just a few. Functional maintenance and wearing comfort are of the utmost importance. The additive manufacturing offers thereby possibilities, which cannot be converted with past manufacturing procedures: Waterproof gypsum, the integration of lightweight structures or structures, which permit a Perspiration, are thereby only some the possibilities for the orthoses of the future.