Latest From the World of Dentistry

As baby boomers head to the dentist in increasing numbers for implants, crowns, and other smile-preserving surgeries, many are encountering a new and unsettling twist on periodontal work--the use of material from cows, pigs, and human cadavers to keep their teeth intact.

If you have a long-festering dental abscess, for example, it may be treated with Emdogain--a protein derived from the teeth of piglets that stimulates growth of the tooth and surrounding bone. Another technique, called guided tissue regeneration, uses membranes rendered from the Achilles tendons of cows. It provides sturdy barricades that keep gum cells at bay, giving teeth and bone a fighting chance to reclaim their rightful place.

Periodontists who use the new procedures laud them as worthy investments in one's dental health.

And if you get a dental implant, it will almost always be preceded by a process called site development, in which the surgeon uses bone harvested from cows or human cadavers to strengthen the implant's foundation. A similar technique may be used before placing a crown, to remedy an injury, or to treat a bone-devouring abscess or periodontal disease.

These procedures are expensive--usually requiring an outlay of at least $1,200--and are rarely covered completely by dental insurance. Periodontists who use them, though, laud them as worthy investments in one's dental health.

"It really has been a revolution," says periodontist Daniel Lippiner, DDS, of New York University. "Until the advent of these materials, many, many teeth were doomed."

The type of biomaterial a periodontist will use depends on the problem being fixed as well as how big it is and where it is in your mouth. It will also depend on your practitioner's preference and training. But such surgeries are undeniably on the rise.

As recently as 5 years ago, three-quarters of the grafting materials used in this type of surgery were taken from other parts of the patient's mouth, says Michael Jeffries of Osteotech, Inc., the largest US supplier of cadaver bone. Now, he says, human and cow bone share the market for half of all such procedures.

Can patients be sure that they are free of the viruses that spread diseases like hepatitis and HIV, or even mad cow disease?

Just how safe are these materials? Can patients be sure that they are free of the viruses that spread diseases like hepatitis and HIV, or even mad cow disease?

While no one can give an ironclad guarantee that the biomaterials used in dentistry will ever result in an unintended complication, experts generally praise their safety.

A review published in the September 1999 Journal of Periodontology concluded that the risk of contracting a fatal brain illness from a cow bone graft "is several orders of magnitude less than that posed by the risk of death related to lightning, tornados, or similarly remote events." There have been no confirmed cases of human mad cow infection in the United States, which bans the importation of any bovine products from countries where the disease has appeared.

There have been no reports of any disease transmission with any of the more than 2 million human bone grafts of all types done in the past 7 years, according to Bob Rigney of the American Association of Tissue Banks. And Jeffries, of Osteotech, says that not only are donor-screening tests for viruses like HIV and hepatitis more sensitive than ever before, but the dozens of steps involved in processing the bone eradicate any disease-causing cells for which tests exist. (After being harvested from arm and leg bones of cadavers, it is demineralized and freeze-dried.) "You can never say 'never,' but the risk is minimal," says Jeffries.

How likely is it that implanted animal or human tissue will save a tooth, staunch an abscess, or securely anchor a crown or implant?

Collectively, such procedures "work 70 to 75% of the time," says Murray Schwartz, DDS, of the Columbia University Dental School. "It's more a risk of time and finances than a health risk," he says.

Autologous bone, which is taken from the patient's own chin or mouth, "is always the best," says Schwartz. Sometimes, though, a patient needs more bone than can be safely and comfortably harvested. Also, the pain, risk, and complications of opening a second surgical site may prompt a surgeon to opt for a foreign graft.

Emdogain, a pig protein, enhances healing and triggers bone growth; and some studies show remarkably positive results.

Many practitioners say that demineralized, freeze-dried cadaver bone is the next-best choice because it contains proteins that trigger the patient's own bone to grow--a true case of the dead communicating with the living. But cadaver bone is harder to get than cow bone, and more expensive. Because the field is new and full of biotech bells and whistles, it's rife with controversies, says John Grbic, DDS, director of the Center for Clinical Research in Dentistry at Columbia University--controversies like "what the right materials are for the right procedure."

Emdogain, the pig protein manufactured by Biora, a Swedish company, is praised by many practitioners for enhancing healing and triggering bone growth; and some studies have shown remarkably positive results. It is undeniably useful, Grbic concedes, but "the people who do these studies have done the procedure thousands of times," and are experts at them. He also notes that certain defects are easier to correct than others are, and young, healthy patients heal better than those who are not.

But a far bigger problem, says Grbic, is access to biomaterials by those who most need them. "The people who tend to have more periodontal disease are typically the ones who can't afford treatment," he says.

While a failure to fix a defect or abscess may not be the fault of the surgeon, the success of an operation involving biomaterials derived from human or animal tissue depends a lot on the skill and experience of the person who performs it, according to Dr. John Grbic of Columbia University.

Before having a procedure, ask the surgeon how many times he or she has performed it and what the chances are of success. No surgery is a 100% sure thing. Operations are more likely to fail if you are a smoker, have diabetes, or have a weakened immune system.

Some patients recoil when told that their periodontist wants to plant a piece of another person or animal inside them. They may have visions of Rob Schneider in Animal or Jeff Goldblum in The Fly. Synthetic fillers exist that can be used in place of bone, but they generally don't work as well in procedures where biomaterials are called for.

Still, it's worth asking about your options, and whether you're a candidate for a simpler, less expensive procedure. "With periodontal disease, things aren't always black and white. There are sometimes other things you can do to smooth out a pocket. You can sometimes take a burr and smooth out the bone and eliminate a hole just by doing that," says Grbic.