may increase susceptibility to infections—both oral and systemic—and have an impact on nutrition.5,36 It may also increase susceptibility to caries and periodontal diseases.

Oral conditions that were, in the past, considered stereotypical of aging are now beginning to be seen in a different light. Research does not support a consensus regarding the causes of diminution of stimulated parotid fluid output, structural changes in epithelium, atrophic change in oral mucosa, and generalized reductions in taste acuity and perception. Evidence suggests that other factors, such as polypharmacy, inadequate nutrition, or systemic diseases may be the precursors of these conditions and not age per se. Other age-related changes in taste, olfaction, and oral sensation, such as touch, temperature, and pressure sensibility, have been observed but have not been well described or documented.34

Tooth Loss

Because tooth loss is the sequela of caries, periodontitis, and trauma, it is a general indicator of the amount of severe oral diseases experienced by an individual or a population.49 The relationship between tooth loss and oral diseases, however, is complicated. Tooth loss also reflects aspects of the dental delivery system that are not disease related—for example, the cost, access to, and utilization of dental services, limitations of existing technology, and variations among treatment options offered and chosen in the dentist/patient interaction. A population's level of tooth loss is therefore a reflection of cultural values as well as the availability, accessibility, cost, and appropriateness of preventive services and treatment.

Despite a steady decline in the rate of edentulousness (toothlessness) over the past several decades, 55 percent of individuals aged 85 or older were edentulous in 1986.39 Edentulism decreases in the younger age groups of the ''second 50": 44 percent of those aged 75 to 84, 30 percent of those aged 65 to 74, 22 percent of those aged 55 to 64, and 12 percent of those aged 45 to 54. There appears to be both a cohort and an aging effect in this trend. Thus, overall edentulousness will be considerably reduced, without any intervention, over the next few decades. Edentulism continues to be more prevalent among older persons below the poverty level, however, and among those with fewer years of education.39

Edentulous people often face severe psychological, social, and physical handicaps. Among older adults, loss of natural dentition can complicate systemic health problems and may interact adversely with certain behaviors. Even when missing teeth are replaced with



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