Dental polymer

Copolymeis of diallyl succinate and unsatuiated polyesters cured by x rays provide wear-resistant coatings of MMA dental polymers (76). 

Acrylic Resins. The first synthetic polymer denture material, used throughout much of the 20th century, was based on the discovery of vulcanised mbber in 1839. Other polymers explored for denture and other dental uses have included ceUuloid, phenolformaldehyde resins, and vinyl chloride copolymers. Polystyrene, polycarbonates, polyurethanes, and acryHc resins have also been used for dental polymers. Because of the unique combination of properties, eg, aesthetics and ease of fabrication, acryHc resins based on methyl methacrylate and its polymer and/or copolymers have received the most attention since their introduction in 1937. However, deficiencies include excessive polymerization shrinkage and poor abrasion resistance. Polymers used in dental appHcation should have minimal dimensional changes during and subsequent to polymerization exceUent chemical, physical, and color stabiHty processabiHty and biocompatibiHty and the abiHty to blend with contiguous tissues. 

Roulet, J.F. "Degradation of Dental Polymers", Karger, Basel, 1987. 

Lin NJ, Drzal PL, Lin-Gibson S (2007) Two-dimensional gradient platforms for rapid assessment of dental polymers a chemical, mechanical and biological evaluation. Dent Mater 23 1211-1220... 

Other researchers have experimentally observed heterogeneity in crosslinked polymers by studying radical concentrations and environment with ESR [101-106], Knowledge of the structure and reactivity of trapped radicals is especially important when considering the long term physical and mechanical properties of dental polymers. Kloosterboer et al. [106] has studied the structure of trapped acrylate radicals while Hamielec and coworkers [102-105] have... 

Roulet JF (1987) Degradation of Dental Polymers. Karger, New York... 

Initiator-accelerator systems for acrylic resins and composites in dental use have been previously reviewed ( ). This report updates the information on these systems in dental polymers. 

Polymer eomposites are inereasingly used for dental applications [30], the durability and aesthetic appeal has made them ideal substitutes for the more traditional amalgam fillings. The dental polymer eomposites are principally composed of an organic matrix and a powdered ceramic phase. The organic matrix is composed of an aromatic or urethane dimethacrylate such as 2,2-bis[4-(2-hydroxy-3-methacryloyl propoxy) phenyljpropane (bis-GMA) with... 

The most common dental polymers, used for prosthetic purposes and restorative dentistry (filling material), are polymethacrylates.1514 The polymerization process performed directly in the dental cavity has to meet strict demands the reaction must be fast at a temperature below 50 °C and it must avoid the formation of a toxic product. These requirements can be fulfilled by UV curing. For example, a mixture of camphorquinone (586), a chromophore (photoinitiator) with an absorption maximum at 468 nm and an amine 587 as a co-initiator (see also Scheme 6.100), initiates a radical polymerization reaction of the acrylate monomer 588 upon photolysis using a conventional blue lamp or laser (Scheme 6.285). 

Next-generation soft contact lenses, dental polymers, surface coatings, and similar materials are produced from compounds of varying structure and reactive functionality. For example, currently in development are new soft lenses that will be manufactured from monomers synthesized with dimethylsil-oxane backbones. The dimethylsiloxane backbone is terminated with a methacryloxy functionality that supplies the site for polymerization. The siloxane provides lens softness. Occasionally the functionality is formed on both ends of the monomer, resulting in undesired properties. The compound BisGMA is a monomer that is polymerized to form hard dental structures. In the monomer synthesis process impurities are coproduced that interfere with the polymerization. Finally, diacetone acrylamide used in a copolymerization process is another specialty monomer that is occasionally contaminated with difficult-to-remove impurities. These three monomers are quite reactive at modest temperature and cannot be purified by distillation. The three examples that are presented here derive from as yet unpublished research (Krukonis, 1982c). 

Dental Polymers. Every year nearly a half billion dental fillings are done, and over a million dentures are constructed. Most of the materials used in each of these cases are polymeric. In addition, over 300,000 dental implants are made each year with either ceramics or polymers (1). The majority of the dental fillings and dentures are made from various copolymers of methyl methacrylate with other acrylics, although some other polymers, such as polyurethanes, vinyl chloride-vinyl acetate-methacrylate copolymers, vulcanized rubber, and epoxies, have been used to some extent. One major problem is aesthetics—the prosthesis must look natural and not discolor (by photoinduction or staining) to any great extent. 

Thermal analyses of other dental polymers have also been reported. The compositions of waxes have been studied by differential thermal analysis (DTA) [64-66] and DMA [67], Conventional DSC and DMA recently showed the superiority of microwave-processed denture base resins to those processed by the slower traditional dental laboratory heating regimen [68], In contrast, comparisons of Tg and other relevant properties for a soft denture liner that was processed by the dental laboratory procedure and a more convenient chairside procedure indicated that both procedures yielded equivalent results [69],... 

J.M. Antonucd, J.W. Stansbury, Molecu-larly Designed Dental Polymers, in R. Ar-shady (ed.). Desk Reference of Functional Polymers, Synthesis and Applications, American Chemical Society, Washington, D.C. (1997), p. 719. 

E. Asmussen, A. Peutzfeldt, Two-step curing influence on conversion and softening of a dental polymer, Dent. Mater. 19 (2003) 466 70. 

F. MUlich, I. Jeang, J.D. Eick, C.C. Chappelow, C.S. Pinzino, Elements of hght-cured epoxy-based dental polymer systems, J. Dent. Res. 77 (1998) 603-608. 

Acrylics Tubing connectors, blood set components, dental polymers, intracellular implants... 

Uses Monomer in anaerobic adhesives and sealants, concrete/dental polymers, photopolymers/resists, inks, glass, reinforced plastics, plasli-sols, and surf, coatings where low shrinkage contributes to adhesion Properties Pt-Co 150 max. clear color m.w. 456 vise. 1100-1800 mPa-s-sapon. no. 230-250 0.2% max. water Toxicology TSCA listed... 

Uses Crosslinker and modifier for ABS, acrylic sheet and rods, PVC peroxide crosslinking agent (mbber) rubber modifier comonomer for crosslinked acrylic/vinyl resins ion exchange resins glaze coatings dental polymers cosmetics paper processing aids adhesives optical polymers leather finishing moisture barrier films ManufJDistrib. Akzo Nobel Aldrich CPS Fluka Hampford Research ... 

Uses Crosslinking agent in casting compds., glass fiber-reinforced plastics, adhesives, coatings, ion-exchange resins, textile prods., plasti-sols, dental polymers, rubber compding. reactive diluent for radiation-cured inks, lacquers crosslinked acrylic resin comonomer Trade Names SR 239... 

Uses Crosslinking agent for peroxide-cured rubber compds., irradiated coatings, polyesters, adhesives, concrete polymers, dental polymers, electronics, inks, plastisols, sealants Trade Names Bisomer E(2)BADMA Bisomer E30W Trade Names Containing Bisomer E(10)BADMA... 

Uses Crosslinking agent for actylic/vinyl resins PVC plastisol comonomer (reduces initial vise, and oil extractability. and improves ultimate hardness, heat distort., hot tear strength, and stain resistance) adhesion promoter hardener used in cast acrylic sheet and rod, contact lens, elastomers, ion exchange resins, dental polymers, adhesives, coatings (paper, plastic), cosmetics, paints, sealants, photopolymers, electronics (photoresists, solder masks)... 

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