In tooth pastes

Earlier, in Chapters 2, 4, and 5, it was pointed out that many foods contain solid particles. Thus the role of the size, shape and hardness of particles in oral perception of texture is of interest. For example, in the confectionary industry the minimum particle size that can be comprehended by the palate is said to be about 25 p,m. Further, particle sizes about 10-15 p,m are considered to be the limit of diminishing effect. On the other hand, in tooth paste, the alumina trihydrate particles with an average diameter 5-20 p,m are used and larger particles are known to contribute to gritty sensation in the mouth (Tyle, 1993). 

Pouret A vessel used lor pouring by the drop. See 62. figures 1-4, Precipitated chalk 1291 An Ingredient in tooth paste. 

Medium-chain (C]o-C]6) alcohol sulfates are used in some parts of the world for liquid shampoos and bubble baths, especially as the alkanolamine- instead of the Na-salt. The salts are also used in dishwashing formulations, - fire fighting foams, hand lotions and household cleaners. Because of their limited water solubility, the sodium salts are used in shampoos, hand cleaners, syndet soaps and foa-mers in tooth paste. 

By far the greatest consumption of pure aqueous phosphoric acid is in the preparation of various salts for use in the food, detergent and tooth-paste industries (p. 524). When highly diluted the free acid is non-toxic and devoid of odour, and is extensively used to impart the sour or tart taste to many soft drinks ( carbonated beverages ) such as the various colas ( 0,05% H3PO4, pH 2,3), root beers ( 0.01% H3PO4, pH 5,0), and sarsaparilla ( 0.01% H3PO4, pH 4.5). 

Some materials have the characteristics of both solids and liquids. For instance, tooth paste behaves as a solid in the tube, but when the tube is squeezed the paste flows as a plug. The essentia] characteristic of such a material is that it will not flow until a certain critical shear stress, known as the yield stress is exceeded. Thus, it behaves as a solid at low shear stresses and as a fluid at high shear stress. It is a further example of a shear-thinning fluid, with an infinite apparent viscosity at stress values below the yield value, and a falling finite value as the stress is progressively increased beyond this point. 

Electric toothbrushes are commonly used in tougher environments than many other consumer household items. In the bathroom, they may be dropped several feet, they are exposed to human saliva (acidic) and various tooth pastes (generally alkaline), they have to withstand hot and cold water and are expected to survive for many years. 

For our day to day use, from tooth paste to TV screen or mobile battery or BMW car or aircraft to missile or anything we need are created by composite materials which we produced only by chemical processes and this stresses the service of chemistry in human endeavor. 

Materials for ESR Dosimetry and Dating. Materials used for retrospective dosimetry of radiation exposure depend on the situation. In addition to human tooth enamel, materials worn by the person, such as shell buttons, or used nearby at the site, such as sugar,32 have been studied to evaluate the radiation dose. On the other hand, materials for ESR radiation dosimetry elements should be well-controlled synthetic chemicals, although natural materials like bovine bones and sugar were proposed in the past. 

Emergency In vivo Tooth Dosimeter Oral Dosimeter. Tooth enamel is only material that records the accumulated radiation exposure dose in the past in a human body. An equipment for rapid dosimetry of teeth without their extraction was fabricated upon demand by Chernobyl medical doctors to judge whether immediate medical care such as spinal transplantation is necessary.97 A portable test apparatus of in vivo human tooth dosimeter consists of a resonator cavity with an aperture and a permanent magnet of Nd-B-Fe alloy (Neomax). The sensitivity is not sufficient due to the low Q factor and non-uniform magnetic field at the tooth. 

Silvestro deals with a Dynamite known as Tooth Paste Explosive. It consists of RDX 84, di (2-ethylhexyI) sebacate 6, polyi so butylene 1 SAE 10W motor oil. 10%. Accdg to A.L. Forchielli, it can be extruded in a width of 1/4 inch and adhere to horizontal metal surface to form a ribbon up to one inch wide and 50 or more inches long. When such a ribbon is initiated by the Corps of Engineers Special Blasting Cap, the result tug detonation cuts the metal into two pieces... 

Xanthan gum shows a good solubility in water, giving a highly viscous solution with a pseudoplastic appearence and a temperature independent viscosity. Xanthan gum is used in pharmaceuticals for its excellent emulsifying and suspending properties. The pseudoplastic properties of this gum enables tooth pastes and ointments both to hold their shape and to spread readily. 

Collapsible Tube Method for Depositing lg nition and Explosive Charges in Electrical Blasting Caps. In this method the colloided soln (or suspension) of an expl (such as a mixt of Pb styphnate with NC lacquer), loaded in a collapsible tube (similar to those used for tooth paste), is squeezed thru a nozzle to be deposited in desired quantity around bridge wire of the igniter... 

Calcium occurs mainly as calcium carbonate and calcium silicate on earth s crust both are found in limestone. By heating the limestone, carbon dioxide is driven away to obtain calcium oxide. Because of its abundance in nature, it is an inexpensive raw material and is used in various industries including in cement manufacture to tooth pastes. It is available in dilferent grades based on the particle size, purity, and reactivity. 

As mentioned, many other molecules exist in the saliva, including nucleic acids (RNA, DNA), several hormones, growth factors and neurotransmitters, amino acids and their derivatives, urea, lactate, citrate, vitamins, creatinine, prostaglandins, several drugs, and chemical constituents of foods, cosmetics, tooth pastes, dental materials, and several other molecules originated from body and environment. 

Oil of sassafras is employed as a soap perfume and for tooth pastes. It is also used as a parasiticide, but in this connection it is not without danger, for it has been recorded that a dog treated with the oil for lice died after a week s treatment. When taken internally and absorbed, it exerts a poisonous effect on the liver, kidneys and heart. 

Bone tissue is created from the minerals and organic molecules that entered the body through drinking water and food and the chemistry of human bone holds information on the diet and life history of the deceased individual. Both the elemental and the isotopic composition of bone are important in studies concerned with dietary reconstruction. Elemental analyses focus on the mineral portion of bone, while isotopic studies are usually aimed at the organic part. Isotopic analyses are also used to study place of origin and past climate as recorded in tooth and bone. The role of archaeological chemistry in the study of prehistoric bones is discussed in further detail in Chap. 4 on Methods, and several examples are provided in Chap. 7, Environment and Diet. 

Our way of life in the past was often defined by how we obtained our food, for example, were we scavengers, hunters, or farmers Did we live from the sea or the land Questions about the kinds of food that our ancestors consumed, the importance of meat, the role of seafood in diet, when farming began, status and gender differences in food consumption are significant issues in archaeology. Information on past diet has traditionally come from a number of lines of analysis the study of preserved animal bones and plant remains, fecal matter, tooth wear and disease, and the physical characteristics of the human skeleton. 

Many towns and cities add fluorides to their water supply, and sodium fluoride (NaF) or tin(ll) fluoride (Snp2) is often added to tooth pastes to prevent tooth decay. You can read about the role of fluorides In preventing tooth decay in the Biology Connection. 

Iron nails have frequently been used in the past both for purposes of medicine and necromancy. A favourite remedy for toothache consisted in hammering a nail into a tree and as the iron rusted so would the toothache disappear. This was much less drastic than having the tooth extracted. Warts have been a nuisance for centuries, though it is difficult to understand why such should have been the case as so many infallible remedies have been prescribed from time to time. The mere touching of a wart by a wise man will effect its disappearance provided an iron nail is offered as a reward for the service but lack of men sufficiently wise may nowadays make this cure somewhat difficult to effect. A simpler remedy hails from the Weald of Kent, namely rub the warts with a piece of raw steak and then bury the latter. As the meat rots so will the wart disappear. 

The useful property of sodium CMC is its ability to increase the viscosity of mixtures to which it is added. At 25 C, water has a viscosity of slightly less than 1 centipoise. A 1 per cent solution of high-viscosity sodium CMC at the same temperature has a viscosity approximately 2,O00 times as great. Thus it finds application as a thickener in textile printing pastes, latex dispersions, lubricants, and the Ukc. As a stabilizer for emulsions ai(d suspensions, sodium CMC is an important ingredient in synthetic detergents to prevent redeposition of soil and is helpful in creams, lotions, tooth pastes, and in many types of oH-in-water emulsions. Its... 

Due to these analytical difficulties Is appears that, particularly in the past, many tooth lead measurements have been performed unsatisfactorily. An interlaboratory comparison program on tooth lead analysis, organized by a lUPAC subcommittee, showed large interlaboratory variations (Stack and Delves, 1982) and in recent years the need for strict quality control has been emphasized repeatedly. 

If dental chemistry continues to progress at the present rate, tooth decay may soon be a thing of the past. Cavities are holes that develop in tooth enamel, which is composed of the mineral hydroxyapatite, Ca5(P04)30H. Recent research has shown that there is constant dissolving and re-forming of the tooth mineral in the saliva at the tooth s surface. Demineralization (dissolving of tooth enamel) is mainly caused by weak acids in the saliva created by bacteria as they metabolize carbohydrates in food. (The solubility of Ca6(P04)30H in acidic saliva should come as no surprise to you if you understand how pH affects the solubility of a salt with basic anions.)... 

The range of personal care products is rather wide, such as shampoos, foam baths, shaving products, creams, tooth pastes. An almost complete review of the use of surfactants for cosmetic and personal care purposes was given in [80], We see it necessary to focus on two aspects of the effect of surfactants on the stability of dispersed systems under different application conditions. 

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