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QUESTIONS SUBMITTED BY THE SUBCOMMITTEE
HEALTH AND OLDER AMERICANS
Question. Doctor, last year the Committee urged NIDR to launch a research and action program for improving the oral health of older Americans. What progress has been made in this effort?
Answer. Following our analysis of data which showed that older people had the most severe oral health problems of any age group, NIDR developed the Research and Action Program for Improving the Oral Health of older Americans and Other Adults at High Risk. The goals of the program are to eliminate oral diseases that lead to tooth loss, improve dental therapeutics and materials, and reduce barriers to self- and professionally provided care. We are committed to providing as much funding and other resources as possible to the program. This will entail targeting specific projects and encouraging other organizations to increase their emphasis on the oral health of adults. A summary of recent progress follows:
The Assistant Secretary for Health established an Interagency Oral Health Coordinating Committee, which has endorsed the program and defined overall objectives and implementation plans for each Public Health Service Agency. For example, the Centers for Disease Control will work with state and territorial dental directors in disease prevention programs.
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The Institute has issued a Request for Applications for Core Clinical Centers focused on the Research and Action Program; a Broad Agency Announcement inviting applications for clinical and demonstration research among adults; and two Requests for Proposals: 1) concerning reasons for tooth loss, and 2) for collaboration with the Indian Health Service to control periodontal diseases in Native Americans at high risk.
We have initiated plans for a 1991 workshop on oral symptoms as an early sign of osteoporosis.
Question. As you know, the oral health of nursing home patients is very, very poor. In your opinion, what should be done to improve the status of dental and oral health of nursing home patients?
Answer. We have supported several studies to assess risk factors and oral health problems common to nursing home patients. Often these relate to ill-fitting dentures and poor oral hygiene--leading to infections, other oral health problems, and a degree of discomfort that diminishes the quality of life and can add to the debility of the patient. There have been studies indicating that the supervised use of antimicrobial mouth rinses or sprays can be used effectively to control or prevent dental disease in patients unable to carry out regular oral hygiene practices. Provision of dental care services remains problematic in many nursing homes, however, and is not within the province of NIDR.
What the Institute can do is support the dissemination of information to patients, family members, and nursing home staff about appropriate oral hygiene practices. Such activities are included in the goals and objectives of the Research and Action Program.
We have also supported demonstration research projects in nursing home patients and continue to support a number of dental investigators who work with older veterans receiving care at VA Medical Centers and nursing homes. We expect that investigators responding to our Broad Agency Announcement will include research and demonstration projects relevant to the oral health needs of nursing home patients.
Finally, NIDR, the National Institute on Aging, and the Department of Veterans Affairs are working to develop collaborative research projects. Among other activities, this has led to an NIDR-DVA collaborative research center on oral health in aging in Florida and to an expansion of research training on geriatric oral health for dental clinical investigators
In the long term, it is envisioned that the emphasis placed by the Research and Action Program on the prevention of oral disease problems in the adult population will enable the elderly to face the aging years with much improved oral health status.
HEALTH RISK FROM SILVER FILLINGS
Question. Dr. Löe, I understand that the old notion that the mercury in the silver colored fillings in our teeth might be poisoning us is having yet another resurgence, scaring and confusing people. There was a "60 minutes" CBS TV show that was sympathetic to the view that the silver colored fillings do cause a health risk.
Doctor, what are the facts with regard to the health risk of silver colored fillings? Do you feel that we should, through your research program, be developing alternative filling materials?
Answer. The silver fillings containing mercury are called amalgams. Introduced 150 years ago, amalgam fillings are the most durable and most inexpensive materials for dental restorations and currently make up 75 to 80 percent of all restorations. About 10 years ago, dental investigators demonstrated that mercury vapor is released from fillings during chewing and other activities that abrade the teeth. Since that discovery, NIDR-supported scientists have been investigating the mechanisms of release, the amounts released and absorbed by the body, and the effects of absorbed mercury on cells. Research to date has not proved that mercurycontaining amalgams are harmful to anyone except those rare individuals who are hypersensitive to mercury.
There is no scientifically sound evidence linking mercury in amalgams to multiple sclerosis, arthritis, mental disorders, or other diseases.
Nevertheless, NIDR continues to investigate these issues and has formed a Task Force which is working with the scientific community to stimulate population studies about the effects, if any, of amalgams on human health. In addition, the Institute continues to support research to develop new and improved nonmercury-containing materials. Three new materials science centers have been funded to further the effort to find alternative materials or to improve the plastic materials already in use to make them as durable as amalgam.
In March 1991, NIDR was asked by the Assistant Secretary for Health to review the benefits of dental amalgam. That study is part of a larger effort by the Public Health Service to review the
benefits and risks of amalgam, under the auspices of its Committee to Coordinate Environmental Health and Related Programs. The Committee's report is scheduled for completion in late 1991. The Dental Products Panel of the Food and Drug Administration also heard expert testimony in March and reaffirmed the safety of amalgam, while acknowledging the need for continued research. On August 26-28, 1991, NIDR, in conjunction with the NIH Office of Medical Applications of Research, will hold a scientific workshop on "The Effects and Side Effects of Dental Restorative Materials." The experts will assess progress toward the development of new dental restorative materials and evaluate the side effects of existing materials, including dental amalgams.
Question. Over this last year there has been a great deal of comment in the press about the risk of HIV-infected dentists spreading the disease to their patients. There is one case of a now deceased Florida dentist who may have spread the infection to three of his patients. I understand that the AMA and the ADA both recommend that HIV-infected dentists should not be involved in pervasive procedures. Is there a need for additional guidelines of any kind?
Answer. In 1987, the Centers for Disease Control urged "universal" precautions in connection with guidelines for infectivity control (meaning that precautions be taken with all patients) and stated that decisions about patient care activities by HIV-infected providers "must be determined on an individual basis." In light of the Florida case, however, tlie AMA and the ADA have issued guidelines advising HIV seropositive practitioners to either abstain from performing invasive procedures or disclose their seropositive status to patients and obtain their informed consent. The AMA also advised physicians at risk of acquiring HIV, and who perform invasive procedures, to determine their HIV status. In contrast, the New York State Health Department has recommended that health care workers with HIV need not tell patients and can continue to perform surgery and other invasive procedures.
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On February 21-22, 1991, the CDC convened a meeting to review the risks of transmission of HIV and hepatitis B (HBV) to patients during certain invasive medical and dental procedures. A risk assessment model based on available disease transmission data had been formulated
a focus of the meeting. New guidelines regarding the practice of health care workers infected with HIV and HBV will be considered by the CDC based on comments presented at the meeting and written comments of professional organizations, government agencies (including NIH and NIDR), private interests, and concerned individuals. In April or May, a draft of the CDC guidelines will appear in the Federal Register, followed by a 60-day period for public comment. After this time, CDC will establish new guidelines.
The available data suggest that, given the low probability of HIV transmission from providers to patients, further restrictions of HIV-infected providers inay not be necessary and that there is currently no need for mandatory testing of patients or providers. The NIDR recommends that prospective studies of disease transmission be conducted in order to assess the actual risk of acquiring the disease.
In the interim, NIDR will continue to support the 1987 CDC guidelines--determine the ability of HBV- or HIV-positive health care workers to continue to practice on an individual basis and be evaluated vis-a-vis their practice habits, knowledge, and physical capability, as judged by their personal physician or peer-review
committee; that barrier techniques and universal precautions be followed for all patient care; and that continued emphasis be placed on disease prevention, professional and public education programs, and other primary public health measures. However, major ethical, medicolegal, social, and civil rights questions have been raised, and many questions remain unanswered. Therefore, we recommend that health care workers who are infected should voluntarily refrain from performing the subset of invasive procedures as defined by their professional organizations.
Question. Dr. Löe, there are approximately 10,000 deaths each year from oral cancers and there hasn't been any significant improvement over the last 10 years. To what extent is your research agenda focusing on this issue? What role does NIDR have in this issue as compared to the role of NCI?
Answer. The new NIDR Long-Range Research Plan for the Nineties emphasizes the need to expand oral health research to include all the diseases and disorders that affect the mouth, the face, and the jaws. Approximately 30,000 individuals--primarily older Americans--are diagnosed with oral cancers each year, and, as has been noted, there are 10,000 deaths. Oral cancers constitute one of the deadliest forms of cancer known. Those who survive may face disfigurement from surgery, destruction of the salivary glands from radiation, and impairments in speaking, chewing, and swallowing.
For all these reasons, it is important to improve our ability to make early and accurate diagnoses and develop improved treatments. We are currently exploring ways to treat or reverse oral cancers with new drugs such as the retinoids and the beta carotenes (vitamin A analogues). Equally important are behavioral interventions to reduce known risk factors such as the use of tobacco and alcohol. Some studies are clarifying why the risk of oral cancer is worse when tobacco and alcohol are both used than when either is used alone.
At the basic science level, NIDR intramural and extramural investigators study the role of oncogenes and oral viruses such as the herpes and papillomaviruses in triggering the transformation of normal cells to malignant ones. To aid this research, NIDR-supported scientists have developed a novel method for growing human cancers in mice--traditionally an exceedingly difficult task. This model should facilitate all cancer research, enabling investigators to observe the growth and spread of any human tumor in the living animal.
NIDR and NCI Directors and staff met at the initiation of these new efforts and are working together to advance research on oral cancers, in this way maximizing resources. One activity will involve the joint development of a health promotion campaign to discourage young boys from using smokeless tobacco products. Baseball players will be used as role models.
Question. Dr. Löe, technology has been available, for a number of years to fuse titanium with the bone and anchor new replacement teeth to this implant. What additional research is required in the area of implant technology?
Answer. Studies both in the United States and in Europe have confirmed that titanium implants can be successfully used to anchor permanent replacement teeth in patients missing all the teeth in one
or both jaws. There is also anecdotal evidence that, when several adjacent teeth are lost, they can be replaced by implant-supported partial dentures. On the other hand, there are essentially no data on the use of implants for single tooth replacements. Nevertheless, there is every reason to believe that such an approach would be more satisfactory than present-day crown and bridgework. The implant would be placed directly in the jaw bone and there would be no need to cap the adjacent teeth. Although additional clinical studies are needed, we believe that ultimately dental implants will become the treatment of choice for any and all missing teeth.
FLUORIDATION AND PUBLIC HEALTH
Question. What is the Institute's position on a recently released report by the National Toxicology Program declaring that fluoridation of public water supplies is no danger to public health and is safe and effective in reducing cavities in affected populations?
Answer. The report in question was requested by the Assistant Secretary for Health, who appointed a subcommittee of his Committee to Coordinate Environmental Health and Related Programs (CCHERP) to conduct a major review of the risks and benefits of fluoride. This request followed the release of data from a National Toxicology Program experiment that found "equivocal" evidence of bone cancer in three male rats fed high dosages of fluoride in drinking water and one male rat fed a mid-high dosage. No bone cancers were found in female rats nor in male and female mice. The term "equivocal" means that the cancers could have occurred by chance alone.
The CCHERP report was released in February 1991 and is the most up-to-date and comprehensive of its kind. NIDR concurs with its findings, the most important being that there is no evidence that fluoride causes cancer of any kind in animals or human beings. This conclusion was based on animal experiments (such as the NTP study) and over 50 epidemiological studies, including an extensive review of cancer incidence and mortality in the United States by the National Cancer Institute. Another finding was that dental fluorosis has increased in nonfluoridated communities since the 1940s and may have increased in fluoridated communities. The cause is largely attributed to the wide availability of fluoride products and evidence of inappropriate and excessive use in some situations. Dental fluorosis (a condition that can range from a very mild staining of enamel to a more severe mottling and pitting of the surface) merits continued monitoring, but the fluorosis that has been reported is generally mild and more of a cosmetic than a health problem. The report affirms the safety and efficacy of water fluoridation, stating that it is the most cost effective and equitable (benefiting rich and poor alike) method of preventing tooth decay, and enumerates areas where additional research is needed.
Question. With the increasing use of fluorides in toothpastes and mouth washes, do you feel that a potential exists for fluoride overdoses in some populations?
Answer. It is important to note that dental fluorosis is a condition that affects developing teeth, so the issue raised concerns the oral health of children. NIDR does not recommend that mouth rinses be used by children aged 5 or under because they may swallow the rinse. Parents should also supervise toothbrushing in younger children to ensure that only a small amount of toothpaste is used on the brush. In terms of the population at large, we believe that it is important to document the incidence and prevalence of dental fluorosis and to monitor total fluoride intake from all sources in the environment, both in fluoridated and nonfluoridated areas, and among various age groups. This is one of the many important recommendations in the CCHERP report and in the NIDR Long-Range Research Plan for the Nineties.