Improved Material From Cow Bones Has Potential to Treat Bone Loss Due to Gum Disease

BUFFALO, N.Y. -- Results of a study conducted by researchers in the University at Buffalo School of Dental Medicine have brought dental surgeons one step closer to using bovine bone implants in humans to help regenerate bone lost through periodontal disease.

The study showed that a new bone-grafting material made from cow bones -- an improvement over similar materials tested for nearly two decades because it contains no bovine proteins -- caused no adverse immune responses in laboratory animals.

The results were reported in the November issue of Journal of Periodontology.

Periodontal disease is the major cause of tooth loss in adults. Bacteria infect the gums surrounding and supporting the teeth and eventually erode the bone that holds them. The ultimate goal of periodontal therapy is to rejuvenate the tissue attachment and regenerate lost bone.

Clinical studies have shown that, in some cases, bone regenerates better with the help of grafts, but currently available grafting materials all have limitations, said Robert E. Cohen, D.D.S., Ph.D., associate professor of periodontology and oral biology at UB and lead researcher on the study.

The patient's own bone is the most successful grafting material, he said, but obtaining it requires additional invasive surgery. Patients frequently refuse materials from human bone banks because of the chance, albeit exceedingly small, of disease transmission, Cohen noted. Grafts of synthetic or natural hydroxyapatite, an inorganic compound that forms the basis of bones and teeth, are biocompatible, but have little capacity to regenerate bone.

The purpose of this study was to determine if an improved form of an experimental material made from cow bones is safe for use in human bone grafts, using the rat as a model.

Cohen and colleagues implanted the bovine bone material and grafting materials known to be safe under the skin of the laboratory animals. Biopsies of the surrounding tissue were taken at several intervals up to eight weeks, and monoclonal antibodies were used to detect any changes in the cells.

"We were looking for cells that become activated at the beginning of the immune response," Cohen said. "An increase in certain cell subsets are associated with antibody formation, which means an immune reaction is beginning. This methods allows us to detect very subtle changes, and if anything bad is happening, we can tell easily."

Results showed no immune response associated with the bovine material, Cohen said.

Grafting materials made from cow bones have been tried experimentally for nearly 20 years, Cohen said, but early grafts failed because patients developed antibodies to proteins remaining in the bovine material. New processing techniques now make it possible to remove all traces of bovine proteins.

Cohen said that if bovine bone-grafting materials are found to be safe and effective in humans, they will provide a readily available, low-cost therapy for treating certain types of periodontal disease.

The study was funded in part by Edward Geistlich & Sons, Ltd., Wolhusen, Switzerland. Members of the research team, in addition to Cohen, were Richard H. Mullarky of Biomedical Composites, Ltd., Carpenterina, Calif.; Bernice Noble, Ph.D., UB professor of microbiology; Robin L. Comeau, dental hygienist in the UB Department of Periodontology, and Mirdza. E. Neiders, D.D.S., UB professor of oral diagnostic sciences.