Dental phosphonic acids

In an earlier investigation by the author [2] di-amides, (I) and (II), were prepared and used in dental adhesive composites. Materials based on acrylic-ester phosphonic acids, (III) and (IV), and used in dental cements were also prepared by the author [3]. 

The following chapters are devoted to applications of phosphorus-based materials. Thus Chapter 8 by Mozsner and Catel deals with the use of polymerizable phosphonic acids (PAs) and dihydrogen phosphates (DHPs) for dental applications. Several PAs and DHPs were synthesized to notably improve the shear bond strength to dentin and enamel, the stability of the adhesive formulation, and the chemical adhesion to tooth tissues. Some of these monomers are nowadays included in commercial dental adhesives. 

Photopolymerization of phosphorus-based (meth)acrylic monomers was largely investigated for dental applications (Scheme 1.4) 20,21,56 69 monomers bore one or two polymerizable groups and phosphoric acid ester, phosphonate, and phosphonic acid moieties were evaluated. When the phosphorus atom was directly linked to a hydrocarbon chain phosphonate ester), the monomers were more resistant to hydrolysis in comparison with phosphoric acid esters. 

Acidic monomers could be phosphates as well as carboxylic, sulfonic, or phosphonic acids. Some examples of carboxylic acid monomethactylates are 4-(2-methactyloyloxyethyl)trimellitic acid (4-MET) and 11-methactyloyloxy-1,1-undecanedicarboxylic acid (MAC-10). Among the functionalized monomers, free-radically polymerizable phosphonic acids (PAs) and dihydrogen phosphates (DHPs) have found wide and intensive applications as adhesive components in enamel/dentin adhesives. In this chapter, a review of the various PAs and DHPs prepared for application in dental adhesives is provided. 

Recently, Garska et al. took an interest in the preparation of methacrylated calix[4]arene PAs (Scheme 8.5). Moszner et al. had previously demonstrated that the incorporation of modified calix[4]arenes into dental materials results in a significant decrease of the polymerization shrinkage. As an extension of this work, the phosphonic acid PA-7 and the diphosphonic acid PA-8 were prepared in three steps, starting from j-tert-butylcalix[4]arene. To evaluate their adhesive properties, those two monomers were... 

Anti-corrosive films can be produced on copper and its alloys by immersion in certain phosphonic acid, RP0(0H>2, solutions. Copper phosphonate salts are formed which increase the solderabiUty and tarnish resistance of the surface. They are superior to copper phosphate films. Metal phosphonate films are useful in some dental products [20] (see below). 

Copol5nners of diethyl (methacryloylox5rmethyl)phosphonate have recently been reinvestigated for possible flame-retardant use (87). Various acrylate and methacrylate monomers with phosphonic acid groups, which aid bonding to dentine, have shown promise for dental restoration purposes (88). Various allyl phos-phonates (89) have been proposed for these uses but none appear to have foimd application. 

Poiyoief ins. Polyethylene can be phosphorylated with phosphorus trichloride and oxygen by a free-radical chain reaction (118,149-151). Side reactions include separate oxidation of the phosphorus trichloride and of the polymer. Hydrolysis gives phosphonic acid structures, which can impart flame retardancy and improved adhesion to surfaces. These materials have been explored for dental and bone therapy applications but no commercial use is known. 

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. 

Various formulations for dental treatment incorporate polymerised phosphonates, which offer certain advantages over phosphates (Section 12.13). Polyvinyl phosphonic add (12.157) and polyethylene phosphonate (12.159) are adsorbed as monolayers on tooth enamel where they resist decay [29]. Copolymers of vinylphosphonic acid and vinylphosphonyl fluoride (12.201) are also adsorbed on tooth surfaces and provide extra resistance to decay by slowly releasing F which can substitute in the tooth hydroxyapatite [30]. 

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