Water fluoridation is the controlled addition of fluoride to a public
water supply to reduce tooth decay. Fluoridated water has fluoride at a
level that is effective for preventing cavities; this can occur
naturally or by adding fluoride. Fluoridated water operates on tooth
surfaces: in the mouth it creates low levels of fluoride in saliva,
which reduces the rate at which tooth enamel demineralizes and
increases the rate at which it remineralizes in the early stages of
cavities. Typically a fluoridated compound is added to drinking water,
a process that in the U.S. costs an average of about $0.92 per
person-year. Defluoridation is needed when the naturally occurring
fluoride level exceeds recommended limits. A 1994 World Health
Organization expert committee suggested a level of fluoride from 0.5 to
1.0 mg/L (milligrams per liter), depending on climate. Dental cavities
remain a major public health concern in most industrialized countries,
affecting 60–90% of schoolchildren and the vast majority of adults, and
costing society more to treat than any other disease. Water
fluoridation prevents cavities in both children and adults, with
studies estimating an 18–40% reduction in cavities when water
fluoridation is used by children who already have access to toothpaste
and other sources of fluoride. There is no clear evidence of other
adverse effects. It is controversial, and opposition to it has been
based on ethical, legal, safety, and efficacy grounds.
Read the rest of this article:
<http://en.wikipedia.org/wiki/Water_fluoridation>
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Today's selected anniversaries:
1398:
The Grand Duke of Lithuania Vytautas the Great and the Grand Master of
the Teutonic Knights Konrad von Jungingen signed the Treaty of Salynas,
the third attempt after the 1384 Treaty of Königsberg and the 1390
Treaty of Lyck to cede Samogitia to the Knights.
<http://en.wikipedia.org/wiki/Treaty_of_Salynas>
1871:
The Criminal Tribes Act entered into force in British India, giving law
enforcement sweeping powers to arrest, control, and monitor the
movements of the members of 160 specific ethnic or social communities
that were defined as "habitually criminal".
<http://en.wikipedia.org/wiki/Criminal_Tribes_Act>
1915:
A German firing squad executed British nurse Edith Cavell for helping
Allied soldiers to escape occupied Belgium.
<http://en.wikipedia.org/wiki/Edith_Cavell>
1928:
An iron lung medical ventilator, designed by Philip Drinker and
colleagues at Children's Hospital, Boston, was used for the first time
in the treatment of polio victims.
<http://en.wikipedia.org/wiki/iron_lung>
2000:
Two suicide bombers attacked the destroyer USS Cole while it was at
anchor in Aden, Yemen, killing 17 of its crew members and injuring 39
others.
<http://en.wikipedia.org/wiki/USS_Cole>
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Wiktionary's word of the day:
belligerent (adj):
1. Of or pertaining to war.
2. Engaged in war, warring.
3. Aggressively hostile, eager to fight
<http://en.wiktionary.org/wiki/belligerent>
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Wikiquote quote of the day:
The concept which assumes that everything in the Church is irrevocably
set for all times appears to me to be a false one. It would be naive to
disregard that the Church has a history; the Church is a human
institution and like all things human, was destined to change and
evolve; likewise, its development takes place often in the form of
struggles.
--Edith Stein
<http://en.wikiquote.org/wiki/Edith_Stein>