March 24, 2014
by Kahaliah Richards
Periodontitis is a troublesome infection of the gums. When the infection causes the bone adjacent to teeth to break down, the teeth come loose. Mandibular bone can also be damaged by cancer, infections and accidents.
With the aid of artificial, foam-rubber-shaped scaffolding, the body can be helped to repair the damage by itself. A new invention made at the Faculty of Dentistry, University of Oslo, Norway, helps the body generate new bone which is as strong as the original.Using this new method, dentists can insert artificial scaffolding that will determine where the new bone tissue will grow.
After a fracture, the bone fragments can knit together only if they are in very close contact. Even if they have the ability to do this, there are major limitations. When a bone fractures, a lot of blood collects at the site of fracture. Blood contains organic molecules that coalesce into long strands. This coagulum is then populated with cells and turn into connective tissue that later calcify. The connective tissue functions as a porous growth platform for bone cells and blood vessels. The bone cells remodel the calcified structure and forms functional bone. New blood vessels help bring nutrients and oxygen.
The outer part of the bone is compact, while the inner part is porous. The porous part contains marrow cells, which are essential for maintaining the skeleton. Its porosity varies according to the type of bone. The problem of this cinario appears when the bone is not in close contact like, as when a big part of the bone is lost after infection, or if it was removed due to cancer, or dameged by radiotherapy. “This is where our invention comes in,” says Ståle Petter Lyngstadaas, Research Dean at the Institute of Biomaterials, Faculty of Dentistry. Along with Professor Jan Eirik Ellingsen, Associate Professor Håvard Jostein Haugen and others, Lyngstadaas has developed and patented an artificial scaffolding that help the body to repair such “critical” damage.
“With our new method, it’s sufficient to insert a small piece of synthetic, bone stimulating material into the bone. The artificial scaffolding is as strong as real bone and yet porous enough for bone tissue and blood vessels to grow into it and work as a reinforcement for the new bone.” “To speed things up, we can take bone progenitor cells or bone marrow that contain committed stem cells from the patients and insert them into the scaffolding. This will cause the process to accelerate.” “When bone needs to be built into defects where the distance between the bone fragments exceeds one centimetre or so, stem cells should be added to obtain a good result, but stem cells are normally not required to solve problems with loose teeth and periodontitis,” Haugen underscores to the research magazine Apollon. Today, damaged bone is repaired by removing tissue from healthy bones, e.g. from the lower jaw, shin, thigh or hip and implanting it in the damaged location. The surgery is uncomfortable and this will cause more morbidity to the patient.
When the patient’s own bone tissue cannot be used, ground bone from other people can be used instead. Unfortunately, this solution is neither sufficiently strong, nor particularly porous. It also has the disadvantage of risk for disease transfer.
To avoid the risk of human disease transfer, ground and heat-treated bone from animals are used. To avoid disease, only animals from closed and controlled herds are used. Any what source for natural bone, after removal of organics and heat treatment the porosity never amount to more than 40 percent, far below the optimum, and the material is too brittle and weak to add support to the regenerated bone.
“One of the advantages of the current methods is that the added bone is gradually devoured by the cells of the body. Our material, on the other hand, will never disappear, but always remain as an integral part of the repaired bone, working as reinforcement. This calls for higher safety requirements,” Lyngstadaas explains. The Norwegian dentists have tested the new method successfully on rabbits, pigs and dogs. In 2014, they wish to undertake clinical studies on patients with periodontitis and damage to the mandibular bone. To establish what method works best, it is advantageous to perform tests on patients with periodontitis in particular. ”
The patients often suffer from bilateral periodontitis. This permits us to compare results by testing the material on one side and have the control on the other within the same patient.”