GUM tissue eaten away by disease can now be restored using a gel that rebuilds teeth’s vital supporting tissue. The gel, which is simple to apply during routine surgery, contains amelogenin, a structural protein which reawakens the processes that govern the growth of teeth in infants.
Patients suffering from periodontitis develop large gaps between their teeth and the surrounding tissue as bone and gum tissue is eaten away. Clinical trials with the gel show that on average, two-thirds of the tissue that has been worn away regrows in patients treated with the gel. In some cases, all the tissue originally lost grows back.
The gel, Emdogain, went on sale in the US last month and in Britain earlier this year. It is already on the market in several European countries including Sweden, where it was developed by Biora, a biotechnology company based in Malmö.
Dentists usually treat periodontitis with flap surgery, in which a small cut is made around a diseased tooth. After cleaning around the root, the gum is stitched to close the fissure. “You get rid of the pocket, but you don’t get any recovery in the tissue supporting the tooth,” says Tomas Hammargren, the president of Biora.
Dentists apply Emdogain during flap surgery by injecting it through the cut to coat the exposed root. Within two days the gel, a modified version of a polymer found in seaweed, biodegrades to leave a coating of amelogenin on the root surface.
“It sets off a chain reaction that rebuilds the supporting tissue,” says Hammargren. First, the protein coating attracts cementoblasts, cells which form another thin coating on the roots called the cementum. Next, ligaments grow into the cementum, anchoring it to bone tissue surrounding the tooth.
More than 300 patients with advanced periodontitis were included in the trials, which were conducted at clinics in the US and Sweden. All had gaps of 5 millimetres or more between their teeth and the surrounding tissue. The trials showed that the gel made worn bone tissue regrow, as well as soft gum tissue. “You get tissue back, so the hole closes up,” says Hammargren. Within 16 months, two-thirds of lost tissue had grown back in treated patients, rising to as much as 70 per cent or more after three years. Some patients regained all the lost tissue.
No such regrowth was seen in patients who received a placebo, and some untreated patients suffered further tissue loss. In half the clinical trials, dentists treated neighbouring teeth in the same jaw either with a placebo or the active gel. This made it easier to show that the gel was working.
Results of these trials-which convinced regulatory authorities in the US, Europe and Japan to approve the gel for sale-are to be published later this year in a special issue of The Journal of Clinical Periodontology.
Gareth Griffiths, secretary of the British Society of Periodontology and lecturer in periodontology at the Eastman Dental School in London, is impressed with the results of Biora’s studies. He says that the method of applying the gel is less fiddly than alternative techniques under development. These require the insertion of membrane barriers to prevent soft gum tissue from rapidly growing into the gap, so giving the ligaments and bone more time to re-establish themselves.