![The Burden of Oral Diseases](https://webarchive.library.unt.edu/eot2008/20090201022307im_/http://www2.nidcr.nih.gov/about/strat-plan/images/burden.gif)
Oral diseases affect the most basic human needs: the ability to eat
and drink, swallow, maintain proper nutrition, smile, and communicate.
Oral health and overall health and well-being are inextricably
connected. Many systemic conditions such as human immunodeficiency
virus (HIV)/AIDS, diabetes, Sjögren’s syndrome, and
osteoporosis have important oral symptoms, manifestations or
complications. The lips, tongue, gingivae (gums), oral mucosa
and salivary glands can all signal clinical disease elsewhere
in the body. Long considered to be localized infections only,
periodontal or gum diseases are now being investigated as potential
risk factors for the development of systemic disease. For instance,
accumulating evidence now points to a possible link between periodontal
diseases and the incidence of premature, low-birth weight babies,
cardiovascular disease, and pulmonary disease. Oral diseases
affect not only the health of the oral cavity and associated
craniofacial structures, but can be detrimental to the overall
health and well-being of individuals.
In the section that follows, we highlight selected oral diseases,
disorders, birth defects and conditions that are uniquely within
NIDCR’s mission to improve the oral health of the nation.
Health Disparities
The substantial gains in the oral health of the nation over
the past generation have not benefited all Americans equally.
The burden of oral and dental disease, particularly untreated
disease, falls heaviest on individuals from lower socioeconomic
groups, which include disproportionately large numbers of racial
and ethnic minorities. Individuals in lower socioeconomic status
groups also have higher incidences of HIV infection and diabetes,
diseases that increase the risk for serious oral, viral, bacterial
and fungal infections. Children in low-income families are particularly
vulnerable to oral health problems. Their nutrition may be poor,
their oral hygiene inadequate, and their access to oral health
care lacking. A partial remedy for addressing health disparities
lies in improving access to effective and appropriate health
promotion, preventive, diagnostic, and treatment services. The
research challenges to reducing health disparities include elucidating
risk factors, identifying and eliminating barriers to health
care, designing better means of care delivery, and designing
educational strategies to reduce risk and enhance health promotion
that are appropriate to the social and cultural frameworks of
the groups in question.
Dental Caries
Dental caries — also known as tooth decay — is not
extinct. Despite tremendous declines in the past three decades,
tooth decay, the end result of a bacterial infection, remains
the single most common chronic disease of childhood in the U.S.
A troubling trend that partly explains the continued prevalence
of caries is the increasing polarization of oral health in the
U.S. — while most children enjoy excellent oral health,
about 25 percent of children 5–17 years of age experience
80 percent of all dental caries in their permanent teeth. Dental
caries begins early in life: 18 percent of preschoolers in the
U.S. have already experienced tooth decay and by age 6–8,
more than half have experienced this disease — making it
5–8 times more common than asthma. By age 17, more than
80 percent of the adolescent population is affected by caries.
Dental caries is also a problem among adults; recurrent caries
and root caries are prevalent among adults and the elderly. The
subset of the general population most prone to caries is also
the most vulnerable: the poor, the very young and the elderly,
and those with compromising medical conditions or disabilities.
Continued research to identify the most effective health education
messages for the prevention of caries, particularly among underserved
populations, is needed. New approaches to diagnose, manage and
prevent caries throughout the lifespan may come from further
research to understand the molecular consequences of the interaction
between host and microbes, and from deciphering the genomic makeup
of bacteria implicated in dental caries.
Periodontal Diseases
Periodontal diseases are a result of infections caused by bacteria
in the biofilm that forms on the teeth in the cul de sac between
the tooth and gum (gingiva). They include a range of clinical
variants — from mild forms such as gingivitis to severe
disease that can destroy the periodontal ligament and surrounding
bone, in some cases leading to the loss of teeth. Almost half
of U.S. adults ages 35 to 44 have gingivitis, a reversible inflammation
of the gingivae, and about one-fourth have the more severe condition
of periodontitis. Severe periodontal disease affects 14 percent
of adults ages 45 to 54, and 23 percent of 65- to 74-year olds.
Tobacco use is a major risk factor for the development and progression
of periodontal diseases. There also is considerable evidence
that diabetes, particularly if poorly controlled, increases the
risk for periodontal disease. At present, treatment of periodontal
diseases includes surgical as well as non-surgical approaches.
Substantial advances in our understanding of how cells adhere
to one another, and increased knowledge about the molecules that
support and regulate nearly all cells are giving clinicians potential
new options to manage periodontal diseases through the regeneration
of tissues.
Tooth Retention and Edentulism
Vast improvements in tooth retention have taken place in the
U.S. over the past three decades. Total tooth loss or total edentulism,
once a relatively common condition among middle age adults is
now most prevalent in older persons, affecting approximately
one-third of adults 65 years and older. There is evidence that
people with impaired dentitions due to missing teeth must choose
foods that do not provide optimal nutrition; in the elderly,
total edentulism and poor oral health can lead to significant
weight loss that can affect overall health. The presence of 21
or more natural teeth has been used worldwide as an indicator
of functional ability. Yet in the U.S. 58 percent of people
50 years or older and over one-quarter of the population over
19 years of age do not have 21 or more natural teeth. Low-income
individuals, and in particular low-income white adults, are most
likely to be totally edentulous. The standard treatment for tooth
loss involves prosthetic devices such as full or partial dentures.
Although these devices initially restore some of the ability
to chew, as people age and lose underlying bone, the fit and
aesthetics of dental prostheses are often compromised. Replacement
of teeth with dental implants provides more natural and stable
function than do dentures, but not every patient is an ideal
candidate for implants. While continuing efforts to prevent tooth
loss, there is a need to evaluate the appropriate replacement
of tooth function, and to pursue evolving technologies that are
enabling the development of biologic materials to repair and
eventually regenerate teeth.
Oral and Pharyngeal Cancer
Oral and pharyngeal cancer is the sixth most common cancer in
the developed world. Each year, an estimated 28,900 Americans
are diagnosed with this disease and more than 7,400 die each
year from it4. The most disturbing
aspect about oral and pharyngeal cancer is the survival rate.
In the U.S. the 5-year survival rate is approximately 50 percent,
a statistic that has not improved over the past twenty years.
African American men suffer the highest incidence of these cancers
and have a much poorer five-year survival rate than do white
men regardless of diagnostic stage. Despite the devastating consequences
of oral cancer, which include impaired ability to chew, swallow,
and speak, and often disfigurement from extensive surgery to
remove parts of the face and oral structures, only 14 percent
of U.S. adults report receiving oral cancer exams that can detect
early disease. Reconstruction and management of the oral cancer
survivor come at a high price both economically and socially.
Not only are more efforts needed to increase public and professional
knowledge about oral cancer and its prevention, there also is
a critical need to develop biomarkers and diagnostic tests that
can be used to improve cancer diagnosis and more accurately predict
the course of the disease. There also is a pressing need to develop
more effective, individualized treatments that spare healthy
tissues and improve quality of life.
Pain and Chronic/ Disabling Conditions
International epidemiologic studies indicate that orofacial
pain occurs in approximately 10 percent of the adult population.
Orofacial pain, by itself or as a symptom of an untreated oral
problem, is often a major cause of poor quality of life. Toothaches
alone are associated with significant morbidity and high economic
cost. Sources of orofacial pain include caries, periodontal diseases,
and neuropathic and musculoskeletal conditions. Orofacial pain
also is a major symptom of temporomandibular muscle and joint
disorders (TMJD) that are estimated to affect 10 million people
in the United States. Orofacial pain may also be caused by conditions
involving the dental pulp (the innermost part of a tooth that
contains blood vessels and nerves) and the area around the root,
leading to symptoms that can range from sensitivity to thermal
changes to severe pain and/or abscesses. Today, pain researchers
know that chronic pain can become a disease in itself, causing
long-term detrimental changes in the nervous system. These changes
may affect resistance to other diseases, as well as effectively
destroy quality of life. There is considerable need for research
that integrates knowledge gained from cell biology, genetics,
molecular biology, imaging technologies, neuroscience, behavioral
sciences and epidemiology to better understand the mechanisms
underlying the causes and progression of orofacial pain and dysfunction
associated with TMJDs and other pain conditions.
Xerostomia
Saliva is a remarkable fluid essential for oral health: it guards
against infections by favoring the accumulation of “beneficial” bacteria
and helping to eliminate other microorganisms, lubricates the
soft tissues of the mouth, buffers acids produced by cariogenic
bacteria, aids digestion, and facilitates speech and swallowing.
Salivary gland hypofunction or obstruction can result in xerostomia
or dry mouth. Xerostomia is a significant health problem, particularly
among the elderly, owing to the some 400 over-the-counter and
prescription drugs, including tricyclic antidepressants, antihistamines,
and diuretics that have xerostomic side effects. The most common
disorder involving the salivary glands is Sjögren’s
syndrome, an autoimmune condition that affects between 1 and
4 million Americans, mostly middle age women. Over 30,000 individuals
who have cystic fibrosis are also at higher risk for salivary
gland dysfunction. In addition, each year an estimated 40,000
people lose salivary gland function as a result of radiation
treatment for head and neck cancer. Whether salivary glands are
irreparably damaged by disease or by radiation for head and neck
cancer, the resulting loss of saliva flow markedly impairs quality
of life. Without adequate saliva, people may experience difficulty
speaking, chewing and swallowing. They may also experience rampant
tooth decay, mucosal infections such as candidiasis, loss of
taste, and considerable oral discomfort. Currently, there is
no effective treatment for this condition. New treatments such
as the potential use of adult and embryonic stem cells for regeneration
of salivary gland tissue and function, and gene transfer technology
may offer new hope for patients with salivary gland damage or
disorders.
Craniofacial Birth Defects or Syndromes
Craniofacial defects are among the most common of all birth
defects. Birth defects and developmental disorders can be isolated
or may be part of complex hereditary diseases or syndromes. Cleft
lip and cleft palate are among the more common birth defects
in the U.S., occurring in about 1 to 2 of 1,000 births. Numerous
other disorders with oral and craniofacial manifestations such
as ectodermal dysplasias, Treacher Collins syndrome, Apert’s
syndrome, and Waardenburg syndrome, while considerably more rare
than cleft lip/cleft palate, also have serious lifetime functional,
esthetic and social consequences. These disorders are often devastating
to parents and children alike. Surgery, dental care, psychological
counseling, and rehabilitation may help ameliorate the problems,
but often at a great cost and over many years. In fact, the lifetime
cost of treating the children born each year with cleft lip or
cleft palate is estimated to be $697 million5.
Exciting advances in genetic studies are shedding light on genes
that are important in forming the head and face, how these genes
function and how they interact with environmental, nutritional
and behavioral factors. Such information may ultimately provide
the information necessary for prenatal diagnosis, the development
of methods to prevent craniofacial birth defects, and the basis
for developing better treatments. The development of biocompatible
naturally-derived materials and biodegradable scaffolds offer
new hope for the treatment of defects resulting from craniofacial
birth defects or syndromes.
4Ries LAG,
Eisner MP, Kosary CL, Hankey BF, Miller BA, Clegg L, Edwards
BK (eds). SEER Cancer Statistics Review, 1973-1999, National
Cancer Institute. Bethesda, MD, http://seer.cancer.gov/csr/1973_1999/,
2002.
5CDC. Economic
costs of birth defects and cerebral palsy – United States,
1992. MMWR 1992;44(no . 37). http://www.cdc.gov/mmwr/preview/mmwrhtml/00038946.htm.
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