I recently read an interesting article written by Catharine Paddock, PhD on a
dental implant that has a slow-release drug reservoir that reduces infection risk. In a laboratory test, the reservoir slowly released a strong antimicrobial agent and showed that the new implant could prevent and eliminate bacterial biofilms, which is a major cause of infection associated with dental implants.
The KU Leuven in Belgium researchers have designed and tested the implant according to a paper published in the journal European Cells and Materials. Dr. Kaat De Cremer, lead author from the Centre of Microbial and Plant Genetics at KU Leuven says that the reservoir in the implant can be filled by removing the cover crew. The implant is made of a porous composite material and the drugs gradually diffuse from the reservoir to the outside of the implant, which is in direct contact with the bone cells. Therefore, the bacteria can no longer form a biofilm.
Bacteria have two life-forms. One form called the planktonic state and exists as single, independent cells, and in the other, they aggregate in a slime-enclosed mass called a biofilm. These biofilms are stubborn and hard to treat. When they become chronic, they are very resistant to antibiotics. Infections of the mouth are often the main reason why dental implants fail, leading to research looking for ways to protect against infection by developing an antimicrobial coating for the implant.
They noted that implant developers are increasingly using materials with rough surfaces because they enlarge the contact and, improving anchorage with bone cells and integration into the bone. The greater surface area also raises the risk of biofilm development. The new implant is a composite of a silicon-based diffusion barrier integrated into a porous, load-bearing titanium structure.
In various lab tests, they filled the reservoir with chlorhexidine, a powerful antimicrobial commonly used as an oral rinse or mouthwash. The chlorhexidine-filled implant stopped Streptococcus mutans, which is a common mouth bacterium that attacks teeth from forming biofilms. Biofilms were also eliminated that were grown on the implant before loading the reservoir. The results prove the implant is effective at both preventing and eliminating biofilms and may potentially be able to prevent and cure infections in patients.
The authors point out that their work is a proof of principle based on tests done in the laboratory and further research should now be done to show that the implants are effective in patients. Several issues need to be addressed including whether the new material fulfills the mechanical requirements of dental implants and whether there is a risk of protein and calcification clogging up the pores. They also note the design of the silicon composite implant suits personalized treatment where different drugs can be loaded into the internal reservoir, depending upon the patient’s individual need. The concept could be translated to any percutaneous implant that can incorporate an internal reservoir as percutaneous fixation devices, as long as this does not compromise the mechanical strength of such load-bearing devices.
Dr Fredda Branyon