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Dental caries, more commonly known as tooth decay or cavities, is
an infectious, transmissible, diet-mediated oral disease that is
largely preventable. It is the most common chronic disease among
US children—being 5 times more common than asthma and 7
times more common than hay fever.1Despite a decline
in dental caries among the population as a whole, this decline has
not translated to all age groups, and profound disparities exist
among certain populations.2 The Centers for Disease
Control and Prevention reported that among children surveyed during
the years 1999 to 2002, 28% of 2- to 5-year-old children
(representing approximately 4 million US children) have visually
evident cavities. Prevalence is apparently trending upward from
the 1988 to 1994 estimation that 24% of young children
have caries.2 Approximately 80% of dental
decay is concentrated in 25% of children.1 In
the United States, children of racial and ethnic minorities or low-income
families experience the worst oral health, are at the highest risk,
and are less likely to obtain timely care compared to their higher-income,
non-Hispanic white counterparts.1 Pediatriciansand
other primary care professionals are in an ideal position to target
these high-risk populations, as children may see their pediatrician
for preventive visits up to 10 times before 2 years of age.
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As dental caries is a disease process that may be established
in infancy, understanding the pathophysiology of dental caries enables
the pediatrician to conduct a dental caries risk assessment; provide
anticipatory guidance and preventive counseling; and, in collaboration
with their dental colleagues, ensure the establishment of a dental
home by age 1, or as soon as possible. The concept of a dental home
is derived from the American Academy of Pediatrics’ definition
of a medical home. The dental home is the ongoing relationship between
the dentist and the patient, inclusive of all aspects of oral health
care delivered in a comprehensive, continuously accessible, coordinated,
and family-centered way.3 Dental caries is the
pathological disease process that leads to the loss of tooth mineral
and eventually cavitation of the tooth surface (“cavity”).
The etiology of dental caries is multifactorial. The primary components
required for dental caries activity to become established are one
or more susceptible tooth surfaces, cariogenic (decay-causing) bacteria,
fermentable carbohydrates (particularly sucrose), and time.
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Demineralization/Remineralization
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Dental caries results from an overgrowth of specific oral bacteria
that are present in dental plaque (the sticky white or yellow “biofilm” that
forms on the tooth surface). The cariogenic bacteria are acidogenic, which
means they produce acids by metabolizing fermentable carbohydrates.
These acids lead to the loss of minerals (demineralization)
such as calcium, phosphate, and carbonate from the tooth. The first
sign of demineralization is a thin white line along the gingival
margin (Fig. 374-1). At this initial stage,
the caries process is reversible through the process of remineralization.
During remineralization, there is an uptake of calcium and phosphate
from the saliva into the tooth enamel, which is facilitated by the
presence of fluoride. Fluoride becomes incorporated into the remineralized
enamel as fluorapatite, which renders the teeth more resistant to
future acidic challenges. If demineralization is not stopped or
reversed, the caries process continues and the result is tooth cavitation
(Fig. 374-1).
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A cavity, or hole in the tooth, is actually a very late stage
in the dental caries process. Thus, dental caries is a dynamic process,
and under normal conditions, there is a balance between demineralization
and remineralization. John Featherstone originally described this
as the Caries Balance model in which pathological factors (which
cause demineralization) battle protective factors (which enhance
remineralization).4 Pathological factors include
cariogenic bacteria, altered salivary flow or function, and poor
dietary habits (ie, frequent ingestion of fermentable carbohydrates).
Protective factors include salivary flow and components, antibacterials,
and fluoride.
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It is well accepted that Streptococcus mutans (SM)
are the primary microbiological organisms associated with the initiation
and progression of dental caries. Early clinical investigations
on the microbiology of dental caries indicated that MS could not be
detected in the mouth of predentate infants, thus suggesting that
a nonshedding oral surface was needed for colonization.5,6 More
recent research demonstrates that MS can be isolated from the tongue7and
oral developmental nodules (Bohn’s nodules) of infants
as early as 3 months of age,8 thus contradicting
earlier reports that MS requires a nondesquamating surface for colonization. The
bacteria can metabolize any fermentable carbohydrate. Sucrose is
considered to be the most cariogenic carbohydrate.1 However,
glucose, fructose, and cooked starches are also metabolized by plaque
bacteria to produce acid.