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BREMEN, Germany: One million dental implants are placed every year in Germany, and often they fail owing to issues such as tissue infections caused by bacteria. In the future, these infections could be prevented owing to a new plasma implant coating developed by researchers at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM) in Bremen. The coating, called DentaPlas, kills pathogens using silver ions and thereby improves the long-term effectiveness of an implant.
Bacterial infection of a dental implant is a dreaded complication, as it carries with it a high risk of jawbone degeneration. Implant placement sets off a race between infectious pathogens and the body’s own cellular defences. If the bacteria win, they form a biological film over the titanium to protect themselves from antibiotics. Once the implant is colonised by germs, the result is an inflammatory reaction, which can result in bone atrophy.
In order to lower the risk of infection and improve the long-term effectiveness of implants, researchers at Fraunhofer IFAM in Bremen have developed a new type of implant coating in cooperation with industry partners. The DentaPlas coating helps prevent the growth of bacteria, thus allowing faster osseointegration. The trick to this lies in combining surface materials with various physical and chemical properties. “We have given the DentaPlas coating a rough texture, which promotes cellular growth, in addition to combining it with a hydrophilic plasma polymer coating, which attracts moisture,” explained Dr Ingo Grunwald, project manager at Fraunhofer IFAM. The researchers have integrated silver nanoparticles into the plasma polymer coating, which is up to just 100 nm thick. The silver nanoparticles dissolve over a period of several weeks, and during that time, they continuously release small quantities of antimicrobial silver ions, which kill bacteria.
“The DentaPlas system consists of three layers, with two plasma polymer layers surrounding a center layer of silver. Within this structure a biocide reservoir is formed, and the outermost layer releases the ions. This is beneficial because it prevents direct contact between the tissue and the silver particles, which can be toxic when exposed,” said developer Dr Dirk Salz. Researchers can change the silver concentration, as well as the thickness of the layers and their porosity. This allows the silver ions to penetrate the outermost plasma polymer layer over a set period deemed necessary for osseointegration. When the silver reservoir is exhausted, no more silver ions are released, thus avoiding any long-term toxic effects.
In trials with finished implants and titanium test samples, the Fraunhofer IFAM researchers demonstrated that the DentaPlas coating is not only antimicrobial but also fully biocompatible and sterilisable. The researchers confirmed the mechanical stability and robustness of the DentaPlas coating in trials using porcine lower jawbones obtained from butcher-shops. Here, they subjected the DentaPlas-coated implants to the rigours of being screwed into place using typical modern dental instruments. The DentaPlas coating passed this stress test with flying colours. Project partner and Fraunhofer spin-off Bio-Gate has successfully transferred the processes of coating the test samples and titanium screws to its own production facilities. The medical technology company is also the manufacturer of the DentaPlas three-layer coating system.
A demonstration unit of the plasma polymer coating is currently available. Researchers will be presenting a dental implant featuring the DentaPlas coating at the MEDICA trade fair in Düsseldorf in Germany from 16 to 19 November at the combined Fraunhofer stand (Hall 10, Booth G05).
From http://www.dental-tribune.com
