Soon, dental implants that kill bacteria, anchor to bone

Scientists in Spain have successfully developed coatings for dental implants that may prevent bacterial infection, eliminate it if it arises, as well as facilitate anchoring to the bone.

Mouth infections are currently regarded as the main reason why dental implants fail.

The fact is that "about 10 per cent of implants have to be removed due to osseointegration problems or to the onset of infections," said Beatriz Palla from University of the Basque Country in Spain.

When it comes to designing strategies to combat these problems, one has to bear in mind the challenge posed by providing the surface of titanium implants with antibacterial properties, and at the same time, by the tremendous resistance that bacterial strains are capable of developing to conventional therapies with antibiotics.

"We had already obtained coatings that facilitate the generating of bone around the implant and thus facilitate anchoring to the bone. In a bid to go a step further, we looked at how to turn these coatings into bactericides," researcher said.

The method they used for this was sol-gel synthesis. Sol-gel synthesis is based on the preparation of a precursor solution (sol) that when left on its own for a while turns into a gel that can be used to coat the surface of the titanium screw, and after heat treatment at a high temperature in the kiln ends up finally being adhered to the screw that will be implanted.

"We used silica as the precursor, because in many studies this compound has been shown to be osteoinductive, so it facilitates one of the objectives we wanted to achieve. What is more, to provide the materials with antibacterial characteristics, we added various antibacterial agents," Palla said.

Researchers developed three types of coatings depending on the various antibacterial agents chosen; each one had a mechanism to tackle bacterial infections, either prophylactically by preventing the bacteria from becoming adhered initially and the subsequent infection, or else by eliminating it once it has developed.

What was needed in the case of prophylactic coatings was "a material with a very long degradation time so that it would remain adhered to the screw and work for as long as possible preventing bacteria from becoming adhered," said Palla.