Dental enamel

Zahne, m. pi. teeth, zahneln, v.t. tooth, indent, denticulate. Zahnelung, /. toothing, indentation, serration, Zahnemaii, n. dental enamel, zahnen, v.t. tooth, indent. — .r. teeth. — gezatmt, p.a. toothed, dentate, dentated, indented. 

The precise nature of the adhesion of the polyelectrolyte cements to untreated dental enamel and dentine has yet to be established. The earliest theory was due to Smith (1968) who speculated that the polyacrylate chains of the cement formed a chelate with calcium ions contained in the hydroxyapatite-like mineral in enamel and dentine. Beech (1973) considered this unhkely since it involved the formation of an eight-membered ring. Beech studied the interaction between PAA and hydroxyapatite, identified the formation of polyacrylate and so considered that adsorption was due to ionic attraction. 

Mizrahi, E. Smith, D. C. (1971). Direct attachment of orthodontic brackets to dental enamel. British Dental Journal, 130, 392-6. 

Silverstone, L. M. (1982). The structure and characteristics of human dental enamel. In Smith, D. C. Williams, D. F. (eds.) Biocompatibility of Dental Materials. Volume I. Characteristics of Dental Tissues and their Response to Dental Materials, Chapter 2. Boca Raton CRC Press Inc. 

Wilson, R.M., Elliott, J.C. and Dowker, S.E.P. (1999) Rietveld refinement of the crystallographic structure of human dental enamel apatites. American Mineralogist, 84, 1406-1414. 

We also have been able to prepare equally strong bioceramic materials of several pure calcium phosphates, which are resorbed much faster into the body as they are converted chemically to living bone by a process that we shall discuss (1-3). We have also synthesized an extremely strong (20,000-lb/in. 2 flexural strength) nonporous dental enamel material which is an excellent material for dental caps, crowns, and dentures (Fig. 3) (4). 

Although adsorbed carbonates on bone mineral and dentine can be easily removed by routine cleaning pre-treatment, the diagenetic fraction has proved more difficult and controversial. Attempts have been made to use sequential acid washing and density separation for bone, as described above, but, at present, the results are rather ambiguous. The carbonate fraction of dental enamel, however, has proved much more amenable, and significant progress... 

Body fluids have a very high supersaturation with respect to hydroxyapatite, which cannot be explained by the small particle size of bone mineral. In fact, they behave as agueous solutions which are in metastable eguilibrium with DOHA. However, the minerals in bone, dentin, dental enamel and dental calculus contain considerable amounts of Na, Mg and CO3, in addition to calcium and phosphate which are the major components. Therefore, the phases mentioned above which all show a solubility comparable to that of DOHA, all come into consideration as components of these minerals. 

Only a few systematic studies have been carried out on the mechanism of interaction of organic surfactants and macromolecules. Mishra et al. (12) studied the effect of sulfonates (dodecyl), carboxylic acids (oleic and tridecanoic), and amines (dodecyl and dodecyltrimethyl) on the electrophoretic mobility of hydroxyapatite. Vogel et al. (13) studied the release of phosphate and calcium ions during the adsorption of benzene polycarboxylic acids onto apatite. Jurlaanse et al.(14) also observed a similar release of calcium and phosphate ions during the adsorption of polypeptides on dental enamel. Adsorption of polyphosphonate on hydroxyapatite and the associated release of phosphate ions was investigated by Rawls et al. (15). They found that phosphate ions were released into solution in amounts exceeding the quantity of phosphonate adsorbed. 

Torell P (1957a) Determination of iron in dental enamel. Odont Tidskr 65, 20-23. 

Cement, dentin, and enamel are bone-like substances. The high proportion of inorganic matter they contain (about 97% in the dental enamel) gives them their characteristic hardness. The organic components of cement, dentin, and enamel mainly consist of collagens and proteoglycans their most important mineral component is apatite, as in bone (see above). 

The most important form of protection against caries involves avoiding sweet substances (foods containing saccharose, glucose, and fructose). Small children in particular should not have very sweet drinks freely available to them. Regular removal of plaque by cleaning the teeth and hardening of the dental enamel by fluoridization are also important. Fluoride has a protective effect because fluoroapatite (see A) is particularly resistant to acids. 

The corrosive effects of sulfuric acid on teeth with chronic exposure are well established." The damage, etching of dental enamel followed by erosion of enamel and dentine with loss of tooth substance, is limited to tbe parts of the teeth that are exposed to direct impingement of acid mist upon the surface. Although etching typically occurs after years of occupational exposure, in one case exposure to an average of 0.23mg/m for 4 months was sufficient to initiate erosion. ... 

Rugg-Gunn, A. J., Maguire, A., Gordon, P. FI., McCabe, J. F., and Stephenson, G. (1998). Comparison of erosion of dental enamel by four drinks using an intra-oral device. Caries Res. 32,337-343. 

Simmer, J. P. (1995). Molecular mechanisms of dental enamel formation. Crit. Rev. Oral Biol. Med. 6, 84-108. 

M. J. Larsen, A. Richards, The influence of saliva on the formation of calcium fluoridelike material on human dental enamel. Caries Res. 35 (2001) 57-60. 

E.C. Morino, T. Aoba, Comparative solubility study of human dental enamel, dentin and hydroxyapatite, Calcif. Tissue Int. 49 (1991) 6-13. 

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