Dec. 20, 2007 Three years after patients were given Nobel Direct dental implants, the risk of the implant loosening has increased even more. A follow-up by researchers at the Sahlgrenska Academy in Sweden shows that eight per cent of the implants are lost.
Nobel Direct was launched in 2004 by Nobel Biocare AB. The implants were considered a great innovation, as they could be screwed directly into the jawbone without having to first lift up the mucous membrane.
"We have followed up 48 patients who were among the first to get the implant. For each passing year, we have been able to see how the problems related to these implants have grown more and more," observes Pär-Olov Östman, a dentist who presented the study December 21 at the defence of his dissertation.
After one year, about five per cent of the implants had been lost, and 20 per cent of the remaining implants showed bone loss of more than three millimetres. The new report indicates that after three years, eight per cent of the implants had been lost, and 25 per cent of the remaining implants showed bone loss of more than three millimetres.
"We believe that the problems related to Nobel Direct result both from the design of the implant and an uneven surface against the soft tissue in combination with the method of treatment recommended by the company," according to Professor Lars Sennerby.
For some time, Nobel Direct was marketed as an implant that was easy to use, and therefore suitable for less experienced dentists. According to the company's marketing, the implant would also counteract marginal bone loss.
"If the implant is inserted in a more conservative manner, avoiding direct load, the results appear to be better. We believe that there are additional implants with similar design that can also cause problems if they are inserted in the same way as Nobel Direct. However, we are unable to draw any certain conclusions regarding these," says Professor Tomas Albrektsson, the head of the Department for Biomaterials Science at the Sahlgrenska Academy.
At the request of the Medical Products Agency, Nobel Biocare AB is now working to clarify certain information in the product information material. The company also markets several other titanium implants that have been scientifically shown to be very safe, including a Brånemark implant with the same patented surface as the Nobel Direct implant in dispute.
The implant is a type of artificial dental root made of titanium. The titanium screw is surgically inserted in the jawbone, and must often become well-secured there so that after several months, it can be used as a foundation for crowns, bridges and dentures. The method was invented by Professor Per-Ingvar Brånemark at the Sahlgrenska Academy in the 1960s. There are several types of titanium appliances, but all are based on titanium being a metal with the unique property of being able to be osseointegrated.
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