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Show Here's Heres IIere's IIeres ' How Hov , to FindOut Find FindOut Out if Dentifrice DentifriceHurts DentifriceHurts Hurts Your TeethUncle Teeth TeethUncle Uncle Sam Tests 25 25Brands 25Brands Brands in Placing Order OrderAtlantic OrderAtlantic Atlantic CityWlth CityWith City -Wlth Wlth -With With - With a nick nIck- nIckel nickel nickel - el and a piece plCce of glass you youcan youcan youcan can make a simple test that thatwIll thatwill thatwill wIll tell you whether your fa- fa favorite fa favorite - . vorite vonte toothpaste will scratch scratchthe scratchthe scratchthe the enamel of your teeth . The test is one that the Umted United UmtedStates UnitedStates UnitedStates States government requires for all alltoothp"1ste alltoothp alltootl toothp"1ste toothp1ste toothp " iste ste purchased purchaccd ; and it was de descrIbed described dcscribed scrIbed at the meeting of the Amer Amer- AmerIcan Amerscan American - ican scan Dental association here by Drs DrsWilmer DrsWilmer DrsWllmer Wilmer Soudcr Souder , physicist , and Irl IrlC IrlC IrlC C Schoonover . , chemist , , of the na- na natIon'11 nation na-tiomi na tiomi - tIon'11 tIon11 tion ' it bureau of standardsUncle standardsUncle standards standardsUncle Uncle Sam buys large quantitiesof quanhbesof quanhbes quantities of toothpaste toothptste : When an order for forsome forsome forsome some 14 000 dozen tubes was con con- contemplated contemplated contemplated - templated , a committee was ap- ap appointed appointed ap appointed - - pointed to write specifications for a asafe asafe asafe safe and effective eiTectIve cleanser for the theteeth theteeth theteeth teeth These specifications now nowadopted nowadopted nowadopted adopted for use , were reported here here1Iust hereMust hereMust 1\Iust 1 Iust Must \ Not Contain Con tam Poison POlson ' Safety for the tissues of the mouth mouthand mouthand mouthand and the teethlas teeth \ was \las las teas the first consld consid conslderatIon consideration consideration eratIon of these men when they met metto metto metto to decIdehat decide \ what \\hat hat that \ must be contained contamed In InUncle inUncle mUncle Uncle Sam's Sams ' toothpaste Next came camethe camethe camethe the question of efficiency in 10 removtng remov remov- removing removing - ing tng foreign materials materwls from the thematter thematter thematter matter of ot . flavor or perfume . A toothpaste must not be exces e"Cces- e"Cces eCces eeccs- eeccs e"CcessIvely eeccssively excessively " - sively either alkaline alkalme or acid , it was wasdecided wasdecided wasdecided decided It must not bo be caustic It Itmust Itmust Itmust must not contain contam arsenic arsemc or other otherpoIsons otherpoisons otherpoisons poIsons It must have a preserva preserva- preservatIve preservative preservative - - tive that v/ill v ill wIll / insure that it keeps 10 in 10good ingood mgood good condition condltlon unt until usedTwenty usedTwenty used usedTwenty Twenty five popular brands of oftoothpaste oftoothpaste oftoothpaste toothpaste were tested against agamst thespecifications the thespecIficatIons thespecifications specIficatIons as adopted tor for use In Ingovernment ingovernment ingovernment government purchasing purchasmg More than thanhalf thanhalf thanhalf half failed fa11ed faded to meat meet the requirements require require- requirements requirements - ments , Drs Souder and Schoonover SchoonoversaId Schoonoversaid Schoonoversaid saId Hardening Hardenmg , separation of in- in ingredtents ingredients in ingredients - gredients gredtents , and fermentation or spoil spOIl- spOIling spoiling spoiling - ing were the most common faults faultsSome faultsSome faultsSome Some showed signs of chemical at- at attack attack at attack - tack upon the tube container , and andthat andthat andthat that v/as v as was / considered undesirableHow undesIrable undesIrableBow undesirableHow Bow How to Make Test . Ten toothpastes among those test test- tested tested tested - ed failed on the test for tor scratchmg scratching scratchmgThis scratchingThis scratchingThis This test , as developed at the na- na natIonal national na national - - tional bureau of standards , can be beused beused beused used by anyone who wants to be besure besure besure sure his dentifrice dentJ.fnce dentJfnce . is not scratch scratch- scratching scratching scratchfng - ing fng the enamel of his teeth A piece pieceof pieceof pieceof of glass and a piece of alloy metal metalof metalof metalof of the size and hardness of a five- five fivecent fivecent five-cent five cent - cent piece are all that are needed neededfor neededfor neededfor for the experiment e'Cpenment eCpenment ' First test the theglass theglass theglass glass for hardness by rubbing rubbmg the theedge theedge theedge edge of the metal piece over it to tobe tobe tobe be sure that the metal alone does doesnot doesnot doesnot not scratch the glass Humanenamel Human Humanenamel Humanenamel enamel and glass both vary in 10 hard hard- hardness hardness hardness - ness nessPlace Place some of the toothpaste to tobe tobe tobe be tested on the glass and rub agam again agamWIth againwith againwith WIth the coin com corn It If scratches result result resultthen . , , then you may expect scratches on onyour onyour onyour your teeth This test is sensitIve sensitIveenough sensitiveenough sensitiveenough enough to detect one part of emery emeryin 10 in one thousand parts of paste . |