Caries composition

Some phosphorus-containing surfactants have bacteriostatic properties. In combination with their physiological acceptance they are used in cosmetics and pharmaceuticals. In mutanase oral anticarie compositions the combination of alkyl phosphates and nonionic surfactants stabilizes mutanase. A dentifrice useful for prevention of dental caries contains 0.5% sodium lauryl phosphate and 1.5% polyoxyethylene (20) sorbitan monooleate [222]. 

The initial products of the reactions between sugars and proteins may enter a cascade of reactions yielding fluorescence, browning, and polymerization of proteins ("cross-linking"). The brown pigments, so-called melanoidins, are polymers whose composition has not yet been established completely. Melanoidins bind calcium and may thus interfere with de- and remineralization in caries. 

Armstrong WG (1964) Modification of the properties and composition of the dentin matrix caused by dental caries. Advances Oral Biol 1, 309-332. 

A variety of materials are employed in the repair of teeth damaged by caries. The main ones are amalgams, composite resins and glass-ionomers (conventional and resin-modified). Table 6 shows the proportion of these materials used in the United Kingdom, based on a comprehensive survey of 9000 restorations placed. 

H.C. Margolis, J.H. Duchworth, E.C. Moreno, Composition of pooled resting plaque fluid from caries-free and caries susceptible individuals, J. Dent. Res. 67 (1988) 1468-1475. 

B.J. Millar, F. Abiden, J.W. Nicholson, In vitro caries inhibition by polyacid-modified composite resins ( compomers ), J. Dent. 26 (1998) 133-136. 

A.R. Veira, I.P.R. De Souza, A. Modesto, Fluoride uptake and release by composites and glass ionomers in a high caries challenge situation. Am. J. Dent. 12 (1999) 14-18. 

J. Arends, G.E.H.M. Dijkmann, A.G. Dijkman, Review of fluoride release and secondary caries reduction by fluoridating composites, Adv. Dent. Res. 9 (1995) 367-376. 

J. Arends, J. Ruben, A.G. Dijkman, The effect of fluoride release from a fluoride-containing composite resin on secondary caries An in vitro study, Quintessence Int. 21 (1990) 671-674. 

G.E.H.M. Dijkman, J. de Vries, A. Lodding, J. Arends, Long-term fluoride release of visible light-activated composites in vitro A correlation with in situ demineralization data, Caries Res. 27 (1993) 117-123. 

K. Kawai, D. Tantbirojn, A.S. Kamalawat, T. Hasegawa, D.H. Retief, In vitro enamel and cementum fluoride uptake from three fluoride-containing composites. Caries Res. 32 (1998) 463-469. 

The most common oral condition and dental emergency is dental caries, which is a destructive disease of the hard tissues of the teeth due to bacterial infection with Streptococcus mutans and other bacteria. It is characterized by destruction of enamel and dentine. Dental decay presents as opaque white areas of enamel with grey undertones and in more advanced cases, brownish discoloured cavitations. Dental caries is initially asymptomatic and pain does not occur until the decay impinges on the pulp, and an inflammation develops. Treatment of caries involves removal of the softened and infected hard tissues, sealing of exposed dentines and restoration of the lost tooth structure with porcelain, silver, amalgam, composite plastic, gold etc. 

Lack of adhesion of a dental restoration to tooth structure results in microleakage at tooth-restoration interface. This occurrence can result in discoloration at the margin of the restoration, or in the formation of caries. Occlusal forces on the restoration and differences between the coeffidents of thermal expansion of the cement and tooth material can lead to leakage. In addition, oral fluids and moisture may affect the adhesion. Microleakage of composite resin restorations has been reviewed by Ben-Amar [233]. Microleakage is not as serious a problem with glass-ionomer cements as it is with resin-based restorative materials, due to reduced polymerization shrinkage [234]. 

Alam, S. Q., Alvarez, J. C., Harris, R. S. Effects of nutrition on the composition of tooth lipids and fatty acids in rats. III. Effects of feeding different oils and fats on caries and on fatty acid composition of teeth. J. Dent. Res. 52, 229 (1973)... 

Early dental caries (incipient lesions) are non-cavitated and limited to the outer enamel surface. Clinically, these lesions are identified as visible white spots when the tooth is air-dried (Fig. 11.1). The incipient lesion is known as a subsurface lesion since the surface appears intact. However, histological investigations have shown that below the surface, there are zones that vary in porosity (voids from mineral loss) as well as biochemical composition (e.g. fluoride, water and carbonate content) [29]. The enamel caries can vary from a depth of 100-250 J.m (for incipient caries) to entirely through the enamel ( 1.5mm deep), at which point the cavitated lesion has extended into the underlying dentin [35]. The diagnostic challenge remains early caries detection and the focus has been on caries lesions that form on the tooth crown affecting the enamel. The remainder of the discussion will therefore concentrate on enamel caries. 

Statistical Analysis The juice composition, as individual amino acids, free amino nitrogen and ratios of certain amino acids and groups of them were entered into a principal component analysis (PCA) using the SAS (Cary, NC) statistical software. The ratios considered were based on the thinking that relative proportions within the amino pool, rather than absolute quantities between alternative substrates might be related to the level of sulfide formation. 

Hutchins, D. A., Campbell, B., Cottrell, M., Takeda, S., and Cary, S. C. (2001). Response of marine bacterial community composition to iron additions in three iron-hmited regimes. Limnol. Oceanogr. 46, 1535-1545. 

Composition of the Phases. In a separate series of experiments the compositions of the gas and liquid phases were determined by a combination of material balances and spectrophotomqtric determinations of the concentration of NO2 in a sample withdrawn from the vessel. The procedure was similar to that described for the determination of a, except that the NO was purified further by passing it through silica gel (12) at dry ice temperature as the gas burette was filled. Measured quantities of NO were introduced to the equilibration vessel until the total pressure was 1 atm. as described previously. After equilibration a sample was withdrawn into a borosilicate glass optical cell, 2 cm. X 18 cm. diameter (.— 5 cc.). The absorbance of the sample at 25°C. was determined with a Cary Model 11 spectrophotometer at 4360A. Using an absorbtivity of 0.0105 0.002 (mm. Hg)" cm." as determined by calibration at a series of NO2 pressures at 25°C. as has been done previously (10, 18, 22, 24), the partial pressure of NOo in the optical cell was calculated. 

A safe composition like white smoke, which consists of hexachloro-ethane, zinc dust and zinc oxide, cari be mixed with a mixer like the one used for concrete. In this case, the light zinc oxide is placed first into the mixer, then hexachloroethane and lastly the heavy zinc dust. 

The most important components are probably the proteins, and the possible roles of these molecules in caries, in particular, have been studied extensively. An obvious inhibitory function of the salivary proteins is the formation of an adsorbed layer on the teeth, the acquired pellicle. For more details on the composition and function of pellicle the reader is referred to chapter 2 and ref. 58. 

Plaque is an essential prerequisite for dental caries to occur, since it is plaque bacteria that produce the acid which dissolves the enamel. However, plaques are of varying cariogenicity, which depends to a large extent on their bacterial composition. In addition, plaque thickness should affect cariogenicity because thickness determines the extent of any acid challenge to the teeth [71, 72], Increasing plaque thickness would also be expected to minimise the potentially protective influence of dissolution inhibitors in saliva. 

Slomiany BL, Murty VLN, Aono M, Slomiany A, Mandel ID Lipid composition of human parotid and submandibular saliva from caries-resistant and caries-susceptible adults. Arch Oral Biol 1982 27 803-808. 

Armstrong WG The composition of organic films formed on human teeth. Caries Res 1967 1 89-103. 

Carlen A, Boijesson AC, Nikdel K, Olsson J Composition of pellicles formed in vivo on tooth surfaces in different parts of the dentition, and in vitro on hydroxyapatite. Caries Res 1998 32 447M55. 

An explanation for the relatively high solubility of smaller lesions may be differences in their chemical composition, when compared to larger lesions. In similar bovine enamel lesions, created in acid-gel systems over 5-15 days, considerable amounts of magnesium were lost [16]. This is consistent with the rapid loss of magnesium (and carbonate) during the early stages of natural caries [19-21]. Further, both species are associated with increased enamel solubility [22], This difference may explain the trend towards decreasing lesion... 

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