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The dentistry-gerontology connection
JABA
The demographic reports concerning the aging population in the United States are evidence to the validity of . . .
The dentistry-gerontology connection Bruce J. B aum , DM D , PhD
-M. n the past few years, Americans have paid noticeable attention to problems as sociated with aging. This interest is prompted by demographic reports pre dicting dramatic increases in the propor tion of our population older than 65 and is demonstrated in recent federal govern ment spending on aging activities. Thus, the newest member of the National Insti tutes of Health is the National Institute on Aging; a presidentially sponsored White House Conference on Aging was held in 1981; between 1965 and 1980, the “ag ing” share of the gross national product doubled. Dentistry, naturally enough, has mir rored this general trend. There are now two journals (Special Care in Dentistry and Gerodontology) concerned specif ically with communicating information about the oral problems of the elderly. The American Society for Geriatric Den tistry has grown in size and exposure. Most impressive is the increasing number of conferences, workshops, meetings, and continuing education programs on the topic of geriatric dentistry. Does geriatric care present any special situation for dentistry or are we just jum p ing on a bandwagon? Is there substance to a dentistry-gerontology connection? A l though research on oral tissues/oral func tions and aging is still in its infancy, I be lieve that we have learned enough in the past few years to be comfortable in suggesting that geriatrics is truly special
for dentistry. In my opinion, there are im portant lessons for our profession in the aging paradigm. In fact, the dentistrygerontology connection provides a m i crocosm of the problems, changes, and challenges that dentistry, as a profession, now faces. Until a few years ago (and in some quar ters still), mention of the geriatric dental patient elicited stereotypical images of a person with grossly altered oral functions (no teeth, xerostomia, and sensorimotor deficits).1,2 As a result of several current studies, it is safe to conclude that such stereotypes are changing and are inap propriate and incorrect descriptors for the next generation of “aged persons.”3"10For example, there are several reasons to ex pect that most older persons are retaining more of their natural dentition. In part, this is the result of more emphasis by the profession on preventive procedures and better compliance by the public.11 Also, caries rates are declining in this country and worldwide, beyond that expected from fluoridation procedures.12 In addi tion, there appears to be an increasing perception among older persons of the need for good oral health. Small-scale studies of essentially healthy persons show that considerable numbers of the elderly are retaining most of their natural teeth.10 Similarly, although a dim inution in masticatory efficiency is found even among healthy, nonmedicated persons, it
is neither universal nor endem ic.6,7 Changes in swallowing are even less common and usually associated with dis ease.6 Also, several reports show modest changes with age in certain speech ges tures, but most reasonably healthy older persons appear fully capable of produc ing esthetically adequate speech.13'15 Another often-studied oral function, with a long history of associated “decremental changes” during aging, is gustation. Yet recent studies have shown that the ability to taste does not decrease noticeably with age.8,9 Changes that do occur are modest in extent. Finally, the purported association of increased age with altered salivary gland function is particularly important, as saliva provides the primary protection for all oral tissues. It contains lubricatory fac tors (mucins) to keep oral tissues hydra ted, pliable, and insulated. There are many antibacterial proteins (for example, lactoferrin, lactoperoxidase, secretory IgA, lysozyme) that regulate oral bacterial colonization patterns, thereby modulat ing dental disease and preventing sys temic infections from the mouth. Saliva contains proteins (statherin and prolinerich proteins) that maintain the secretions supersaturated with respect to calcium and phosphate, allowing for remineral ization of incipient carious lesions. Saliva also buffers acid produced by oral bac teria and thus he lp s lim it enam el demineralization. Lastly, saliva provides JADA, Vol. 109, December 1984 ■ 899
PERSPECTIVE
a medium for dissolution and presenta tion of tastants to the gustatory apparatus. If alterations in saliva production occur with age, the oral tissue manifestation among the elderly would be adverse and widespread. However, recent studies offer no sup port for the notion that salivary gland dys function3-5 is associated with normal ag ing. Although a few specific instances of altered performance of glands in aging persons have been reported,5,16 dim inu tion of salivary gland secretory function is not an inevitable consequence of grow ing old. What are the implications of these find ings? Foremost is recognition that many oral problems are not part of normal aging physiology. In the past, these may have been casually ascribed to aging, and thus often not addressed. They may, however, represent drug reactions or disease pro cesses, and active intervention may not only be desirable, but necessary. Thus, patients with, for example, oral dryness should not be told that their oral dryness is a sign of growing older. Dysfunction of the oral tissues, although rarely lifethreatening, certainly impinges consid erably on the quality of life. Dryness and difficulties in swallowing or tasting often have accumulating negative effects on a patient, especially if no hope for im provement can be offered. By showing that such changes are not normal, these data open the way for de veloping effective treatment and man agement tools with a goal of bettering the daily status of elderly patients. Such a de velopment w ill lead to a broadening in the definition of dental practice as well. Dentists, as the health care professionals responsible for the oral cavity, w ill need to diagnose, and treat or manage prob lems with salivary dysfunction, altered taste, dysphagia, other sensorimotor defi cits, mucositis, and infections. This need (a more diverse mix of skills required to manage a numerically significant seg ment of our society that often may be medically or pharmacologically com promised) is the strongest case to suggest that geriatrics is a microcosm of the chal lenges currently facing our profession. Recently, the American Dental Associ ation’s Special Committee on the Future of Dentistry prepared a draft report of pro fessional concerns with strategies for ac tio n .17 The report listed factors that would affect dentistry’s future: changing patterns of dental disease, distinct demo graphic shifts, increased access to dental care, and larger numbers of dentists prac ticing in nontraditional settings. On the basis of their analyses of trends, “the committee identified five principal rec o m m e n d a tio n s th at s h o u ld be im plemented to prepare the profession for the challenges of the future.”17 The third 900 ■ JADA, Vol. 109, December 1984
recommendation was to broaden practi tioners’ clinical skills and mix of services offered to the public. Geriatric dental practice today provides a training ground for tomorrow. The report notes the in creasing need within dentistry for practi cal skills in oral medicine and stomatol ogy and for more (and even required) hospital training for dentists. A similar recommendation has been made recently by Bohannan18 as part of a symposium addressing the impact of declining caries prevalence. Such skills, beyond those presently stressed in dental school curriculums and continuing education pro grams, are needed now for managing many elderly patients. Another of the five recommendations, the need to stimulate research and de velopment, can also find current, fertile areas in aging. Stereotypes tend to dis courage the study of a problem. If the mouth is assumed to be going downhill with age, why would there be a need for geriatric or gerontologic studies? How ever, if oral diseases are not generalized in an aging population, documented changes are more interesting and stimu late further investigation. This is impor tant not only to the “ applied” discipline of aging but also may lead to worthwhile basic science contributions. An example may serve to illustrate this point. As part of our studies on salivary gland function during aging, we use rat parotid gland cells in vitro as a model. We observed dis tinct differences in the responsiveness of young and old animals to a-adrenergic stimuli.19 Conversely, no differences in muscarinic-cholinergic responses were noted.20It had been thought that both re ceptor responses were mediated by an identical signal mechanism. This could not be the case, given the age difference. Use of an aging paradigm has proved ex tremely useful for us in understanding how a-adrenergic receptors elicit the physiologic responses. For many years, studies of development have been impor tant to understand biologic processes and yield insights beyond mere descriptions of stages or events. Analogously, the aging m odel m ay be useful experi mentally, particularly so for understand ing situations relevant to the health of the oral cavity. In being able to understand the prob lems of the geriatric patient, and to man age those problems effectively, dentistry is now faced with many of what are con sidered to be its future challenges (clini cal and scientific). Most importantly, the spectrum of oral problems (traditional dental plus stomatologic) to be faced re quires broadened didactic and clinical training not commonly available. Geriat rics may therefore provide dentistry with an opportunity for forays into curriculum flexibility, alternative practice settings,
research models, and expanding perspec tives. There is a substantive dentistrygerontology connection, or at least there should be.
__ ________________________ JWCM Essays of opinion on current issues in dentistry are published in this section of JADA. The opinions ex pressed or implied are strictly those of the authors and do not necessarily reflect the opinion or official policies or position of the American Dental Associa tion. Dr. Baum is clinical director and chief, clinical in vestigations and patient care branch, National Insti tute of Dental Research, National Institutes of Health, Bethesda, MD 20205. Address requests for reprints to the author. 1. MacHudis, M. Dentistry for the elderly. In Reichel, W., ed. Clinical aspects of aging. Baltimore, Williams & Wilkins Co, 1978. 2. Storer, R. The oral tissues. In Brocklehurst, J.C., ed. Textbook of geriatric medicine and gerontology. London, Churchill-Livingstone, 1978. 3. Baum, B.J. Evaluation of stimulated parotid saliva flow rate in different age groups. J Dent Res 60:1292-1296, 1981. 4. Baum, B.J.; Kousvelari, E.K.; and Oppenheim, F.G. Exocrine protein secretion from human parotid glands during aging: stable release of the acidic proline-rich proteins. J Gerontol 37:392-395,1982. 5. Chauncey, H.H., and others. Parotid fluid com position in healthy aging males. Adv Physiol Sci 28:323-328,1981. 6. Baum, B.J., and Bodner, L. Aging and oral motor function: evidence for altered performance among older persons. J Dent Res 62:2-6,1983. 7. Feldman, R.S., and others. Aging and mastica tion: changes in performance and in swallowing threshold with natural dentition. J Am Geriatr Soc 28:97-103,1980. 8. Weiffenbach, J.M.; Baum, B.J.; and Burghauser, R. Taste thresholds; quality specific variation with human aging. J Gerontol 37:372-377,1982. 9. Grzegorczyk, P.B.; Jones, S.W.; and Mistretta, C.M. Age-related differences in salt taste acuity. J Gerontol 34:834-840,1979. 10. Baum, B.J. Characteristics of participants in the oral physiology component of the Baltimore longitu d in a l study of aging. Com m unity Dent Oral Epidemiol 9:128-134,1981. 11. Mandel, I.D. Preventive dentistry for the el derly. Spec Care Dent 3:157-163,1983. 12. Glass, R.L. Introduction to the first interna tional conference on the declining prevalence of den tal caries. J Dent Res 61:1304,1982. 13. Wilcox, K.A., and Harii, Y. Age changes in vocal jitter. J Gerontol 35:194-198,1980. 14. Benjamin, B.J. Frequency variability in the aged voice. J Gerontol 36:722-726,1981. 15. Sonies, B.C.; Baum, B.J.; and Shawker, T.H. Tongue motion in the elderly: initial in situ observa tions. J Gerontol 39:279-283,1984. 16. Baum, B.J.; Costa, P.T., Jr.; and Izutsu, K.T. Al teration in sodium handling by human parotid glands during aging: failure to support a simple two stage se cretion model. Am J Physiol 246:R35-R39,1984. 17. American Dental Association’s Special Com mittee on the Future of Dentistry. Chicago, American Dental Association, 1983. 18. Bohannan, H.M. The impact of decreasing caries prevalence: implications for dental education. J Dent Res 61:1369-1377,1982. 19. Ito, H., and others. Modulation of rat parotid cell a-adrenergic responsiveness at a step subsequent to receptor activation. J Biol Chem 257:9532-9538, 1982. 20. Bodner, L., and others. Multiple transduction mechanisms are likely involved in calcium-mediated exocrine secretory events in rat parotid cells. J Biol Chem 258:2774-2777,1983.
The demographic reports concerning the aging population in the United States are evidence to the validity of . . .
The dentistry-gerontology connection Bruce J. B aum , DM D , PhD
-M. n the past few years, Americans have paid noticeable attention to problems as sociated with aging. This interest is prompted by demographic reports pre dicting dramatic increases in the propor tion of our population older than 65 and is demonstrated in recent federal govern ment spending on aging activities. Thus, the newest member of the National Insti tutes of Health is the National Institute on Aging; a presidentially sponsored White House Conference on Aging was held in 1981; between 1965 and 1980, the “ag ing” share of the gross national product doubled. Dentistry, naturally enough, has mir rored this general trend. There are now two journals (Special Care in Dentistry and Gerodontology) concerned specif ically with communicating information about the oral problems of the elderly. The American Society for Geriatric Den tistry has grown in size and exposure. Most impressive is the increasing number of conferences, workshops, meetings, and continuing education programs on the topic of geriatric dentistry. Does geriatric care present any special situation for dentistry or are we just jum p ing on a bandwagon? Is there substance to a dentistry-gerontology connection? A l though research on oral tissues/oral func tions and aging is still in its infancy, I be lieve that we have learned enough in the past few years to be comfortable in suggesting that geriatrics is truly special
for dentistry. In my opinion, there are im portant lessons for our profession in the aging paradigm. In fact, the dentistrygerontology connection provides a m i crocosm of the problems, changes, and challenges that dentistry, as a profession, now faces. Until a few years ago (and in some quar ters still), mention of the geriatric dental patient elicited stereotypical images of a person with grossly altered oral functions (no teeth, xerostomia, and sensorimotor deficits).1,2 As a result of several current studies, it is safe to conclude that such stereotypes are changing and are inap propriate and incorrect descriptors for the next generation of “aged persons.”3"10For example, there are several reasons to ex pect that most older persons are retaining more of their natural dentition. In part, this is the result of more emphasis by the profession on preventive procedures and better compliance by the public.11 Also, caries rates are declining in this country and worldwide, beyond that expected from fluoridation procedures.12 In addi tion, there appears to be an increasing perception among older persons of the need for good oral health. Small-scale studies of essentially healthy persons show that considerable numbers of the elderly are retaining most of their natural teeth.10 Similarly, although a dim inution in masticatory efficiency is found even among healthy, nonmedicated persons, it
is neither universal nor endem ic.6,7 Changes in swallowing are even less common and usually associated with dis ease.6 Also, several reports show modest changes with age in certain speech ges tures, but most reasonably healthy older persons appear fully capable of produc ing esthetically adequate speech.13'15 Another often-studied oral function, with a long history of associated “decremental changes” during aging, is gustation. Yet recent studies have shown that the ability to taste does not decrease noticeably with age.8,9 Changes that do occur are modest in extent. Finally, the purported association of increased age with altered salivary gland function is particularly important, as saliva provides the primary protection for all oral tissues. It contains lubricatory fac tors (mucins) to keep oral tissues hydra ted, pliable, and insulated. There are many antibacterial proteins (for example, lactoferrin, lactoperoxidase, secretory IgA, lysozyme) that regulate oral bacterial colonization patterns, thereby modulat ing dental disease and preventing sys temic infections from the mouth. Saliva contains proteins (statherin and prolinerich proteins) that maintain the secretions supersaturated with respect to calcium and phosphate, allowing for remineral ization of incipient carious lesions. Saliva also buffers acid produced by oral bac teria and thus he lp s lim it enam el demineralization. Lastly, saliva provides JADA, Vol. 109, December 1984 ■ 899
PERSPECTIVE
a medium for dissolution and presenta tion of tastants to the gustatory apparatus. If alterations in saliva production occur with age, the oral tissue manifestation among the elderly would be adverse and widespread. However, recent studies offer no sup port for the notion that salivary gland dys function3-5 is associated with normal ag ing. Although a few specific instances of altered performance of glands in aging persons have been reported,5,16 dim inu tion of salivary gland secretory function is not an inevitable consequence of grow ing old. What are the implications of these find ings? Foremost is recognition that many oral problems are not part of normal aging physiology. In the past, these may have been casually ascribed to aging, and thus often not addressed. They may, however, represent drug reactions or disease pro cesses, and active intervention may not only be desirable, but necessary. Thus, patients with, for example, oral dryness should not be told that their oral dryness is a sign of growing older. Dysfunction of the oral tissues, although rarely lifethreatening, certainly impinges consid erably on the quality of life. Dryness and difficulties in swallowing or tasting often have accumulating negative effects on a patient, especially if no hope for im provement can be offered. By showing that such changes are not normal, these data open the way for de veloping effective treatment and man agement tools with a goal of bettering the daily status of elderly patients. Such a de velopment w ill lead to a broadening in the definition of dental practice as well. Dentists, as the health care professionals responsible for the oral cavity, w ill need to diagnose, and treat or manage prob lems with salivary dysfunction, altered taste, dysphagia, other sensorimotor defi cits, mucositis, and infections. This need (a more diverse mix of skills required to manage a numerically significant seg ment of our society that often may be medically or pharmacologically com promised) is the strongest case to suggest that geriatrics is a microcosm of the chal lenges currently facing our profession. Recently, the American Dental Associ ation’s Special Committee on the Future of Dentistry prepared a draft report of pro fessional concerns with strategies for ac tio n .17 The report listed factors that would affect dentistry’s future: changing patterns of dental disease, distinct demo graphic shifts, increased access to dental care, and larger numbers of dentists prac ticing in nontraditional settings. On the basis of their analyses of trends, “the committee identified five principal rec o m m e n d a tio n s th at s h o u ld be im plemented to prepare the profession for the challenges of the future.”17 The third 900 ■ JADA, Vol. 109, December 1984
recommendation was to broaden practi tioners’ clinical skills and mix of services offered to the public. Geriatric dental practice today provides a training ground for tomorrow. The report notes the in creasing need within dentistry for practi cal skills in oral medicine and stomatol ogy and for more (and even required) hospital training for dentists. A similar recommendation has been made recently by Bohannan18 as part of a symposium addressing the impact of declining caries prevalence. Such skills, beyond those presently stressed in dental school curriculums and continuing education pro grams, are needed now for managing many elderly patients. Another of the five recommendations, the need to stimulate research and de velopment, can also find current, fertile areas in aging. Stereotypes tend to dis courage the study of a problem. If the mouth is assumed to be going downhill with age, why would there be a need for geriatric or gerontologic studies? How ever, if oral diseases are not generalized in an aging population, documented changes are more interesting and stimu late further investigation. This is impor tant not only to the “ applied” discipline of aging but also may lead to worthwhile basic science contributions. An example may serve to illustrate this point. As part of our studies on salivary gland function during aging, we use rat parotid gland cells in vitro as a model. We observed dis tinct differences in the responsiveness of young and old animals to a-adrenergic stimuli.19 Conversely, no differences in muscarinic-cholinergic responses were noted.20It had been thought that both re ceptor responses were mediated by an identical signal mechanism. This could not be the case, given the age difference. Use of an aging paradigm has proved ex tremely useful for us in understanding how a-adrenergic receptors elicit the physiologic responses. For many years, studies of development have been impor tant to understand biologic processes and yield insights beyond mere descriptions of stages or events. Analogously, the aging m odel m ay be useful experi mentally, particularly so for understand ing situations relevant to the health of the oral cavity. In being able to understand the prob lems of the geriatric patient, and to man age those problems effectively, dentistry is now faced with many of what are con sidered to be its future challenges (clini cal and scientific). Most importantly, the spectrum of oral problems (traditional dental plus stomatologic) to be faced re quires broadened didactic and clinical training not commonly available. Geriat rics may therefore provide dentistry with an opportunity for forays into curriculum flexibility, alternative practice settings,
research models, and expanding perspec tives. There is a substantive dentistrygerontology connection, or at least there should be.
__ ________________________ JWCM Essays of opinion on current issues in dentistry are published in this section of JADA. The opinions ex pressed or implied are strictly those of the authors and do not necessarily reflect the opinion or official policies or position of the American Dental Associa tion. Dr. Baum is clinical director and chief, clinical in vestigations and patient care branch, National Insti tute of Dental Research, National Institutes of Health, Bethesda, MD 20205. Address requests for reprints to the author. 1. MacHudis, M. Dentistry for the elderly. In Reichel, W., ed. Clinical aspects of aging. Baltimore, Williams & Wilkins Co, 1978. 2. Storer, R. The oral tissues. In Brocklehurst, J.C., ed. Textbook of geriatric medicine and gerontology. London, Churchill-Livingstone, 1978. 3. Baum, B.J. Evaluation of stimulated parotid saliva flow rate in different age groups. J Dent Res 60:1292-1296, 1981. 4. Baum, B.J.; Kousvelari, E.K.; and Oppenheim, F.G. Exocrine protein secretion from human parotid glands during aging: stable release of the acidic proline-rich proteins. J Gerontol 37:392-395,1982. 5. Chauncey, H.H., and others. Parotid fluid com position in healthy aging males. Adv Physiol Sci 28:323-328,1981. 6. Baum, B.J., and Bodner, L. Aging and oral motor function: evidence for altered performance among older persons. J Dent Res 62:2-6,1983. 7. Feldman, R.S., and others. Aging and mastica tion: changes in performance and in swallowing threshold with natural dentition. J Am Geriatr Soc 28:97-103,1980. 8. Weiffenbach, J.M.; Baum, B.J.; and Burghauser, R. Taste thresholds; quality specific variation with human aging. J Gerontol 37:372-377,1982. 9. Grzegorczyk, P.B.; Jones, S.W.; and Mistretta, C.M. Age-related differences in salt taste acuity. J Gerontol 34:834-840,1979. 10. Baum, B.J. Characteristics of participants in the oral physiology component of the Baltimore longitu d in a l study of aging. Com m unity Dent Oral Epidemiol 9:128-134,1981. 11. Mandel, I.D. Preventive dentistry for the el derly. Spec Care Dent 3:157-163,1983. 12. Glass, R.L. Introduction to the first interna tional conference on the declining prevalence of den tal caries. J Dent Res 61:1304,1982. 13. Wilcox, K.A., and Harii, Y. Age changes in vocal jitter. J Gerontol 35:194-198,1980. 14. Benjamin, B.J. Frequency variability in the aged voice. J Gerontol 36:722-726,1981. 15. Sonies, B.C.; Baum, B.J.; and Shawker, T.H. Tongue motion in the elderly: initial in situ observa tions. J Gerontol 39:279-283,1984. 16. Baum, B.J.; Costa, P.T., Jr.; and Izutsu, K.T. Al teration in sodium handling by human parotid glands during aging: failure to support a simple two stage se cretion model. Am J Physiol 246:R35-R39,1984. 17. American Dental Association’s Special Com mittee on the Future of Dentistry. Chicago, American Dental Association, 1983. 18. Bohannan, H.M. The impact of decreasing caries prevalence: implications for dental education. J Dent Res 61:1369-1377,1982. 19. Ito, H., and others. Modulation of rat parotid cell a-adrenergic responsiveness at a step subsequent to receptor activation. J Biol Chem 257:9532-9538, 1982. 20. Bodner, L., and others. Multiple transduction mechanisms are likely involved in calcium-mediated exocrine secretory events in rat parotid cells. J Biol Chem 258:2774-2777,1983.