Fluoride toothpastes

Mouthrinses containing fluoride consist of a concentrated solution that is prepared for use at daily or weekly intervals. As is the case for toothpastes, fluoride from mouthrinses is retained by the dental plaque and increases the concentration in saliva [172]. Mouthrinses have the advantage that their viscosity is low [173], which is aided by the use of ethanol as at least part of the carrier liquid. This enables mouthrinses to penetrate into interproximal regions, and hence carry the fluoride to parts of the tooth that are difficult to access by other means, for example, with toothpastes. 

When food lodges between teeth, acids form that dissolve tooth enamel, which contains the mineral hydroxyapatite, Ca5(P0,j)30H. Tooth decay can be reduced by adding fluoride to toothpaste. Fluoride replaces the hydroxide in hydroxyapatite to produce the corresponding fluorapatite, Ca3(P04)3p, and calcium fluoride, CaF, both of which are less soluble in... 

Tm II)fiuoride, Snp2, stannous fluoride. M.p. 213°C. Formed from Sn and aqueous HF. Forms complexes, e.g. MSnFj. Used in toothpastes. 

Representative Method Ion-selective electrodes find application in numerous quantitative analyses, each of which has its own unique considerations. The following procedure for the analysis of fluoride in toothpaste provides an instructive example. 

M NaOH until the pH is between 5 and 5.5. Transfer the contents of the beaker to a 1-L volumetric flask, and dilute to volume. Standards are prepared by placing approximately 1 g of a fluoride-free toothpaste, 30 mL of distilled water, and... 

Why is a fluoride-free toothpaste added to the standard solutions ... 

Fluoride-free toothpaste is added as a precaution against any matrix effects that might influence the ion-selective electrode s response. This assumes, of course, that the matrices of the two toothpastes are otherwise similar. 

The following data were collected for the analysis of fluoride in tap water and in toothpaste, (a) For the analysis of tap water, three 25.0-mL samples were each mixed with 25.0 mL of TISAB, and the potential was measured with an F ISE relative to a saturated calomel electrode. Five 1.00-mL additions of a standard solution of 100.0-ppm F were added to each, measuring the potential following each addition. 

The calcium pyrophosphates are utilized primarily as dental abrasives in fluoride-containing toothpastes. Typically, a mixture of P- and y-Ca2P202 achieves a balance of abrasivity and fluoride compatibiUty. 

Several crystalline condensed phosphates may also be formed by the dehydration of monosodium phosphate (MSP). Maddrell s salt exists as Form 11 (high temperature MaddreU, NaPO -ll, insoluble metaphosphate-11) and Form 111 (low temperature MaddreU, NaPO -lll, insoluble metaphosphate-111). Both forms are highly polymerized and difficult (slow) to dissolve in water. Mixtures of the two forms are marketed as a dental abrasive for toothpaste formulations containing soluble fluoride. Maddrell s salt is also used with disodium phosphate as a cheese emulsifying aid. 

The principal commercial use of stannous fluoride is in toothpaste formulations and other dental preparations, eg, topical solutions, mouthwash, chewing gum, etc, for preventing demineralization of teeth (21—23) (see Dentifrices). 

Several agents deUvered via toothpaste inhibit the accumulation of dental calculus. Pyrophosphate salts, with or without a methoxyethylene—maleic acid copolymer, and zinc salts have given positive results in clinical trials (5). Pyrophosphates were added as potassium or sodium pyrophosphate or mixtures at a level of about 2—6%. The zinc salt was zinc citrate [546-46-3] (0.5—2.0%) or zinc chloride [7646-85-7] (2.0%). The products all contained fluoride in addition to the calculus inhibitor. The anticaries activity of the fluoride was not compromised (6). 

The incidence of dental caries has decreased dramatically in recent years. It has fallen to such an extent as to reduce the need for professional dental health services related to caries significantly. The cause is not clear, but water fluoridation, addition of fluoride to toothpaste, and other modes of fluoride adrninistration are generally conceded to be important contributors to the phenomenon and the American Dental Association recommends use of a fluoride toothpaste for all patients (10). 

NaF for water fluoridation, wood preservatives, the formulation of insecticides and fungicides, and use as a fluxing agent. It is also used to remove HF from gaseous Fz in the manufacture and purification of Fz-SnFz in toothpastes to prevent dental caries,... 

Though dental afflictions constitute a very significant disease entity, these have received relatively little attention from medicinal chemists. (The fluoride toothpastes may form an important exception.) This therapeutic target Is, however, sufficiently Important to be the focus of at least some research. A highly functionalized piperazine derivative that has come out of such work shows prophylactic activity against dental caries. Condensation of the enol ether 1 of thiourea with ji-pentylisocyanate gives the addition product 1J. Reaction of this with diamine 78, derived from piperazine, leads to substitution of the methylthio moiety by the primary amine, in all likelihood by an addition-elimination sequence. There is thus obtained ipexidine (79). ... 

Modern toothpaste has to do many things. It must have abrasives to scour off bacterial films. It must have fluorides to harden the teeth against decay. It must have a strong enough pleasant... 

The most recognized toothpaste ingredient is probably the class of compounds known as fluorides. Stannous fluoride was the first to be used in toothpaste because, unlike sodium fluoride, it did not lose its effectiveness when combined with the abrasive most common at the time, calcium phosphate. Later, sodium mono-fluorophosphate came into popular use because it too could be used with the common abrasives. 

When hydrated silica became the abrasive of choice, sodium fluoride could be used, and it has become the most widely used fluoride in contemporary toothpaste. 

Hydrated silica is the transparent abrasive used in gel toothpastes and in the clear parts of striped toothpaste. It has come into common use in white opaque toothpastes as well, because of its compatibility with sodium fluoride. 

Stannous fluoride is used in toothpastes and dental rinses to protect tooth enamel from attack by bacteria—cavities (also known as dental caries). It was the first fluoride used for that purpose, in the toothpaste Crest. 

The addition of fluoride ions to domestic water supplies (in the form of NaF) is now widespread and has resulted in a dramatic decrease in dental cavities. Fluoridated toothpastes, containing either tin(II) fluoride or sodium monofluorophos-phate (MFP, Na2FP03), are also recommended to strengthen tooth enamel. 

C04-0008.Tooth enamel consists, in part, of CajfPOq)] (OH). Tin(II) fluoride (toothpaste labels call it... 

Often the need or desire can be satisfied by a substance that is presently on the market, but it is projected that a new product will either do a betteijob, cost less, or require less time and effort. The toothpastes produced before 1960 did a respectable job of cleaning teeth, but the addition of fluoride made them better cavity preventa-tives, and those toothpastes that added fluorides became the best sellers. Orange juice could be shipped in its natural form to northern markets, but frozen concentrated orange juice occupies one-fourth the volume and costs less to the consumer. TV dinners and ready-to-eat breakfast cereals cost more than the same foods in their natural state, but they reduce the time spent in the kitchen. All of these items resulted from research followed by design. 

Stannous fluoride, a compound of tin and fluorine, is much less dangerous. It is added to drinking water and toothpaste to strengthen the enamel in the teeth of the user. Another compound of fluorine is teflon, a plastic made of carbon and fluorine, which is used in kitchenware. The fluorine-containing compound freon is used in air-conditioners and refrigerators, and is harmless. 

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