Laser Polishing For Dental Implants
AACHEN, Germany: Researchers have developed a flexible and cost-effective apparatus to polish implants automatically. The project team has managed to reduce the time needed to process dental and blood-carrying implants while maintaining their high bio- and haemocompatibility.
The surface quality of an implant plays a significant role if it is to be used in the body successfully. For example, bone implants require a porous structure so that cells can grow into them well. Other implants, however, need as smooth a surface as possible to prevent bacteria from attaching to them and the surrounding tissue from being damaged.
The MediSurf project has made these kinds of implants the object of its research. The seven partners of the project, funded by the German Federal Ministry of Economics and Technology and led by the Fraunhofer Institute for Laser Technology ILT, recently presented their research results in Aachen, Germany.
The main focus was the optimisation of the surface of the titanium ventricular assist system INCOR, made by Berlin Heart. The project aimed at reducing production time while guaranteeing high haemocompatibility. This means that the implant should leave blood corpuscles undamaged and corpuscles should be prevented from settling on the implant as far as possible. Blot clots are prevented from forming, thus significantly reducing the risk of heart attacks and strokes.
Initially, the researchers had to establish whether laser-based polishing of the surface could obtain the same level of haemocompatibility as with conventional manual polishing. In order to answer this, the team at the Fraunhofer ILT developed a process to polish blood-carrying implants with lasers. “We are able to reduce the micro-roughness to such an extent that the implant exhibits the best possible haemocompatibility. However, we began with very little information on exactly what quality the surface had to have for this purpose,” explained project leader and engineer Christian Nüsser from the Fraunhofer ILT. “For this reason, we had to test various parameters to reach the desired result.”
The haemocompatibility of the implants was tested at the Münster University Hospital. The result: laser-polished implants exhibit the same haemocompatibility as those polished manually, but laser polishing is 30 to 40 times faster than manual polishing. With large lot sizes, this means an enormous reduction in production costs. In addition, laser polishing has a higher reproducibility. It guarantees a homogeneous smoothness over the entire surface of a free-form geometrical component, even on corners and edges, which are difficult to reach when polished manually. Unlike in conventional processes, the edges are not rounded off when polished with lasers, thus guaranteeing high geometrical accuracy of the component. Another advantage of laser polishing lies in its far cleaner and more environmentally friendly process. In contrast to manual polishing, no polishing or abrasive materials are used, leaving no chemical residue on the implant.
Alongside this polishing process, a prototype apparatus has been developed at the Fraunhofer ILT for automated laser polishing of implants. For the first time, scientists have developed a glove box with a six-axis articulated robot, which can grasp the implants and process a complete series of them on its own. This automated machine engineering makes the entire process less expensive, more flexible and appropriate for industrial series production.