New-York tribune., 1886-07-31
HOW TEETH AXE DESTROiED By IRON.

From The NcdicIl Record
An instructive and valuable paper on TINS
site OF Sew-York In jane by George W. We'd. NJ. D..
d. d. Dr. We'd declares tha' tAe clinical operation
that water increases the destructive energy OF
the tncure OF the chloride OF ron upon the enamel OF
the teeth more than any other nud snd as an iustra
ton he states that the effect OF adding water 10 sim
pie solution OF the chloride OF iron, devoid o Tree aed
give basic salts OF iron and tie separation OF tree
hydrocblorc acid, In other w)rGs IN Iae presence
of water u double decomposition takes place. his
statement OF the fact that physicians hitherto
when prescribing the tncture OF lrOn nave almost III
varaby directed their patients to iieey dlute me rop
Win water must not oh.y poNo ~ ~ w w 80, ~
men, but 10 the large number OF people VINO resof' 70
Dr. WeId showed conclusivey that the tincture OF the
chloride OF iron OF ofcna strength had but little, II
any eiirot upon the enamel structure OF tooth wnen
immersed In the for period OF twelve hours but
thnt when immersed in a solution OF the tnoture and
water In the proportion OF one ounce Oh water 70 one
As An Illustration OF this phenomenon the doctor
stated that whrn piece OF zine Is immersed In strong
suphuric acid M 500 has been ooscrvedtbat the acid
effect the structure OF the L'hc ont II te
water added the acid the zinc Is at once destroyed
40 thai Il IA not entirely matter OF the strength OF the
fluids, the quantity oflron or acd Is concerned.
but u matter OF construction or soluOiy; Inc Lno III
the strong suphuric acid Is protected IN tho same man
that the tooth which immersed III 'ne STRONG shc
OF CHI orde Of ron s protected VIZ tho surface 10
blocked up with salts OF iron insoln3e IN ALCOHOL
which prevents chemical action Ia The case OF the In'
1t s the suphale OF zinc resulting from tho nrst action
and nsolube she concentrated acid that forms pro-
teetng the surface OF tho zinc; tho addition
dissolves this protecting suphate anu renuers
further chemical action possible Ia the case OF tooth
a solution OF Inc tlnclurc sluat
action takes place. VIZ, the oxide ol iron nrst fOn'
protects the enamel from immediate chemical action on
account OF its COR pact adherence To lts surface
10 Illustrate sti further Dr. Weld called attention 10
two speclmens uf winch lad been immersed III the
tlpcttIre and alcohol ane compared them with teeth
which had been Immersed with the tncturo aud waer
Here II was observed that although the ALCOHOLIC sou
ton used conained quantity OF the tlneturc
aud posssessed apparently the same relative strength
and the teeth FOR the same length OK time YET
no injurious effect produced on their lime sails
The reason Is attributed to the fact that acohol 10
a dehydrating compound. and the peroxide which Is
formed In tho alcoholic solution Is OF tho anhydrous
FORM character very compact sdh-rlng closely
to the surface Of the tooth. thereby preventing nme-
diate chemical action whilo on the other hand In mo
presence Of water peroxide. which Is precpitated
is form, Is occulent In character does not
well adhere surface OF the tooth, leaving tne
free hydrochloric acid tho solution 10 unite Win the
lime salts with greater facility. ...
The teeth Immersed In an ounce OF the elxir o, hs %
OF roD drachm OF the tncture OF tue
chloride aided. for period OF twenty iour hours
apparently chemical effect Oh tho enamel; put
with the same quantity OF water and tho tincture the
enamel was completely destroyed The elixirs arc com
posed or nearly twenty five cent OF alcohol the
sncr Of which, In tho sroug solution oI tue
uncture and IN the alcoholic solution, anords pro
| lection 10 the enamel OF the teeth III tho manbe
de,crihed But It 10 bc noted that when tooth
Immersed IN solution OF tho tincture aud simple syrup
In The above proportions. the enamel is but HIVE
affected. This is duo TO mechanical reason, or con
dillon OF nulcity OF the solutor, G., tao presence q