A team of researchers at Aalto University, Finland, developed a method to select new surface treatment processes for orthopaedic and dental implants that may reduce the risk of infection. Implants are commonly made from metals, such as titanium alloys, which are made porous during processing used to prepare them for medical use. While this can ensure good contact between the implant and the bone, it can also allow bacteria to adhere and grow on both the surface and the inside, leading to an increased risk of infection.

A thin coating of a biomaterial called Hydroxyapatite (HAP) or bioactive glass (BAG) is typically applied to implants to alter surface properties. Such coatings improve the body’s ability to recognize a foreign object in a more friendly way and promote implant integration into surrounding tissues. During the heat treatment process, excessive stresses can cause premature cracking and removal of the coating layer. This can lead to the development of unsuitable compounds and increase the risk of infection.

The team said that they proved that by adding another compound called beta-tricalcium phosphate, such stresses are reduced, the biomaterial coating is better preserved, and by reducing bacterial adhesion, the implant surface is allowed to function in an optimal way. This research is significant in the battle against the spread of drug-resistant bacteria.

Aalto University and its partner manufacturers have already started developing new experimental devices for advanced testing of biomaterials at the conditions most close to life. Besides proving developed technology, it will allow high-throughput screening of the biomaterials with substantially better properties.

The research was conducted at Aalto University and supported by Tekes, the Finnish national innovation agency, and by the EU FP6 project “Meddelcoat”.