Dental implants.

Dental Implants

Ordinary dentures, generally made of plastic, are custom-fitted to match and adhere to the upper or lower jaw or made to clamp on to remaining teeth with metal supports or bridges.

But today there are dental implants, which add a method of attaching the denture with metal anchors directly and permanently to the jaw bone with no need to ever be removed by the wearer.

Dental scientists have discovered materials that will bond with bone and withstand the pressure created by biting and chewing. The bonding process is called "endosseous [within the bone] integration." Refined surgical techniques and follow-up have reduced the likelihood of the implant loosening, breaking, or being rejected by the body.

At least 10,000 dentists implant dental prostheses today, compared to 1,000 or so five years ago. Dental implants are now being done at a rate of about 6,000 to 7,500 a year.

"We have the ability to functionally and aesthetically rehabilitate the oral invalid to a state of excellent dental health," says Paul H.J. Krogh, a Washington, D.C., oral and maxillofacial (jaw) surgeon and president of the Academy of Osseointegration, which represents 1,150 oral surgeons, other dental professionals, assistants, technicians, physicians and scientists.

"Not every patient is a candidate for implants," cautions the American Dental Association (ADA), headquartered in Chicago, which represents 146,000 dental professionals and students.

The ADA points out there is no substitute for natural teeth, that implants will never function as well as the real thing. And the association's position is that implants are not suggested for cosmetic purposes alone.

"The best implant is a natural tooth," echoes Albert Guckes, a prosthodontic consultant at the dental clinic of the National Institute of Dental Research, Bethesda, Md. "With today's technology we can salvage badly damaged teeth, and that's the way to go," he says.

If you are thinking of having dental implants, consider the following: . Determine if it is possible to save your own teeth. . Will you be able to keep the schedule required for implant surgery and follow-up? Some implants require many visits and a second stage of surgery. It may take as long as four to six months or more before the implant is completed. . Know what to expect in the way of pain, soreness, and possible long-term restrictions to your diet. You also may have to wear temporary devices. . Will you be able to follow special oral hygiene instructions and maintain a schedule of regular dental checkups that may go on for years? . Your body might reject the implant after a few months or a few years. Are you prepared to accept that possibility? . Medical risks are inherent in implant surgery, just as in any surgical procedure. In implant surgery, risks include sinus perforation, local and systemic infection, and paresthesias (abnormal or impaired skin sensation). . Dental implants are expensive. The cost of surgery, prosthesis, and associated professional services for a single implanted tooth is approximately $1,000 in Augusta, Ga., according to Ralph McKinney, Jr., chairman of the department of oral pathology of the Medical College of Georgia in Augusta. In Washington, D.C., patients can expect to pay from $4,000 to $6,000 for a permanent lower bridge and up to $10,000 to $12,000 for a full fixed upper denture bridge or $18,000 to $24,000 for both upper and lower implants. Elsewhere, dentists and surgeons doing dental implants report that charges range up to $30,000.

Don't expect financial help from health or dental insurance plans. Since the implant devices are considered experimental by insurance companies, they will probably not be covered until they are proven effective, according to the Health Insurance Association of America.

Twenty thousand dentists have trained for implant work in the United States. The scope of their training varies from having viewed instructional videotapes to having invested years in apprenticeship to others experienced in the procedure. The procedure is not regulated, and there are no accepted criteria for skill or experience that must be met to perform the procedure. The ADA has not formally recognized implant surgery as a specialty.

D. Gregory Singleton, D.D.S., of the FDA's Center for Devices and Radiological Health, in Silver Spring, Md., suggests talking with others who have had implants when making a decision about going to a particular dentist or oral surgeon.

Four general designs of devices are in use in implant dentistry today. The two most frequently used, according to Barry E. Sands, biomedical engineer at the Center for Devices and Radiological Health, are: . One- and two-stage cylindrical implants. These are inserted directly into holes drilled into the jawbone as sockets for screws to anchor a single false tooth, groups of false teeth, or entire rows of replacements. In two-stage implants, the cylinder is fitted into the bone and the gum is sutured closed over the device until the area heals and the device bonds to the bone around it. Then the surgical site is reopened to allow abutments to be placed in the cylinders, and the prosthesis is attached. . Blade types. Shaped to fit channels cut lengthwise into the jaw bone, blades have openings to accept bone regrowth through their framework. Tiered vanes above the gum line allow attachment of the prosthesis, which is generally done at the same time as the surgery.

The other types of devices -- pin- and tooth-shaped -- are less frequently implanted today and are generally used only for replacing individual teeth.

Because of the routine presence of bacteria in the mouth, there is a risk of infection of the tissue or bone surrounding the implant. There also is some risk that the additional stress of the implant on bones in the jaw will speed up bone resorption and lead to implant failure and possibly a toothless future. Persistent pain or discomfort, speech problems, nerve injury, and damage to adjacent teeth are rare but possible complications of implants.

Conditions that can rule out dental implants include hypertension, heavy smoking, alcohol and drug abuse, chronic illnesses such as diabetes, bone deterioration, and bruxism (habitual tooth grinding), according to the University of Detroit's Dr. Arnold Mentag.