Ettinger reviewed the studies on caries rate
and distribution in the 20th century and concluded
that it had different patterns in the world, which
are related to the degree of development and level
of industrialization. Populations in the
industrialized countries have decreasing caries
rates in children and an increasing number of
retained teeth in the elderly, while the opposite
situation is found in the developing countries. This
this review paper nearly a century ago in three
articles that discussed what he termed the
"wasting of tooth tissue" and its causes. Root caries
was once considered a disease for which the
elderly population had their teeth extracted and
replaced with removable prostheses. At present,
root caries is becoming a new area of focused
research in dentistry, as more people are living to
an advanced age and retaining their natural teeth.
With advanced age, there is more gingival
recession, which leaves the root surface exposed
to the oral environment and leads to an increase in
the root caries rate. Ettinger, who has reviewed
many studies related to the prevalence and
incidence of root caries in different areas of the
U.S., found that more than half of the elderly
people have had root caries and that root caries
increase with age.