Page images

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, the 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.

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 to serve as 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 may 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.

[ocr errors]

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. Loe, 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. Loe, 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.


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 cause

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. 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.




Senator HARKIN. Now, we turn to the National Institute of Allergy and Infectious Diseases. Dr. Fauci, we have your budget request for $976.7 million, which is about 7.7 percent more than last year. I noticed that $459.3 million, or 47 percent, of your request is devoted to AIDS.

Again, we welcome you back and thank you again for your leadership of your Institute. And we would be delighted to hear your statement at this time.

Dr. FAUCI. Thank you very much, Mr. Chairman.

The National Institute of Allergy and Infectious Diseases is responsible for the conduct and support of basic and clinical research on infectious diseases, many of which cause extraordinary morbidity and mortality throughout the world. One of these, as you mentioned, is the human immunodeficiency virus which causes AIDS.

In addition, we conduct and support research on the immune system which is the defense system of the body against the emergence of infections and certain neoplasms. I have come before this committee several times to discuss the research advances in these areas, and they have been truly extraordinary. However, these advances in biomedical technology have created a dilemma with their own new challenges. The public's expectation of what biomedical research can do to alleviate suffering and death caused by human diseases now clearly surpasses our available resources not only in research, but in health care delivery.

One way to bridge this gap is to prevent certain diseases before they occur, and this is particularly feasible with infectious diseases. Historically, vaccines have resulted in the saving of millions of lives and immeasurable financial costs. In this regard, the recent advances in technology have positioned us quite well to develop new vaccines for infections for which we thus far have no vaccines and more effective and safer vaccines for infections for which we already have existing vaccines.

In this regard, this past year basic and clinical research conducted by the NIAID in collaboration with the National Institute of Child Health and Human Development has resulted in the licensing of two new vaccines to protect infants against Haemophilus influenzae type b, the leading cause of bacterial meningitis in young children. This is an important advance, but just a start in NIAID's commitment to perform the basic and clinical research necessary to implement the children's vaccine initiative. The aim of this initiative is to develop an oral vaccine that provides lifelong immunity to the major diseases of childhood throughout the world.

On another note, there has been a disturbing rise in morbidity and mortality due to asthma among inner city children, most of whom are minorities. NIAID recently announced eight awards to establish a network of centers to study this problem. I can tell you more about this later on.

History in general and AIDS in particular has taught us that new and emerging microbes are a constant threat to our survival. NIAID is committed to remain at the forefront of research to strengthen our basic science alert system against this ever-present threat.


In the area of gene therapy, which you have just heard about from some of my colleagues, ÑÍAID intramural scientists have recently demonstrated that a factor secreted by cells called gamma interferon could dramatically restore the genetically determined defective capacity of white blood cells of individuals with chronic granulomatous disease to kill potentially lethal bacteria. This is an important breakthrough in our ability to modify cellular gene function as opposed to replacing absent or defective genes, a manipulation which is akin to gene therapy.

Finally, time does not permit in this opening statement to give a summary of our AIDS activities, but I look forward to discussing this with you in our question period.

Thank you, Mr. Chairman. [The statement follows:]

[ocr errors][ocr errors]
« PreviousContinue »