Methacrylate dental resins

Superacryl Dental a.s. (Praha) Poly (methyl methacrylate) dental resin... 

Various types of hardness meters are available from ATS FAAR inclnding International Rubber Hardness Degree, Shore, Rockwell, and Fiat for testing against ASTM, ISO, UNI, DIN and FIAT specifications. The Martin Instrument Company is also a supplier of Shore hardness meters. Hardness measurements have recently been reported on methacrylate dental resins [31], polymeric coatings based on polyester resin, PU and acrylic acid [32], polyacrylamide [33] and aged PE [34]. 

UV-curable liquid crystalline urethane methacrylates Dental resin-based composites Buruiana etal. (2011)... 

Hydroxy functional methacrylates ate used in automotive coatings, dental resins, contact lenses (qv) and a variety of other appHcations (64). 

Many initiator-accelerator systems that contain accelerators other than amine have been suggested for vinyl pol3rmerization, but only a few have been employed in dental resins. Substitution of p-toluenesulfinic acid, alpha-substituted sulfones and low concentrations of halide and cupric ions for tertiary amine accelerators, yields colorless products (43-48). Most of these compounds have poor shelf-life. They readily oxidize in air to sulfonic acids which do not activate polymerization. Lauroyl peroxide, in conjunction with a metal mercaptide (such as zinc hexadecyl mercaptide) and a trace of copper, has been used to cure monomer-pol3rmer slurries containing methacrylic acid (49-50). Addition of Na salts of saccharine to monomer containing an N,N-dialkylarylamine speeds up pol)rmerization (51). 

Dental resin formulations were prepared by the combination of SOCM with an ethoxylated bisphenol A dimethacrylate (EBPAD, Diacryl 101, Akzo Chemie America) in a 26.6 73.4 wt ratio which corresponds to a 41.5 58.5 mol ratio. Resin samples were activated by the addition of various photo-initiators and were polymerized as unfilled films between Mylar sheets. The cured samples were stored for 24 h at 37 C and then removed from the Mylar. The degree of conversion of the combined methacrylate groups of SOCM and EBP AD as well as the conversion of the spiro vinyl group of SOCM were determined by comparison of the IR spectra of the uncured resin with those of the polymerized films. The methacrylate double bond absorption at 1637 cm and the spiro vinyl absorption at 880 cm were monitored with the aromatic band at 1585 cm utilized as an internal standard reference 14),... 

Isobutyl methacrylate Methyl methacrylate dental prods., antiplaque Chlorhexidine digluconate dental resins Cyclohexyl methacrylate dental wax compounds Ceresin dentals... 

Methylene lactone monomers have been considered for their use in dental resins (52). The effect of the more reactive methylene lactone monomer on mechanical properties and the degree of conversion of the polymers was examined. The addition of a small amount of a-methylene-y-butyrolactone to bis-glycidyl methacrylate significantly increases the conversion. However, additional a-methylene-y-butyrolactone 10-30% does not further increase the conversion. Therefore, an incompatibility between the two monomers is assumed (52). 

The addition-reaction product of bisphenol A and glycidyl methacrylate or an epoxy resin and methacrylic acid is bis-GMA 2,2- 7Z5 4-(2-hydroxy-3-methacryloxypropoxy)phenyl propane (Fig. 5). Bis-GMA can therefore be classified as a dimethacrylated epoxy, although it does not contain a reactive epoxy group. Bis-GMA is the most commonly used prepolymer in dental composite restorative materials. Several similar compounds have also appeared as substitutes for Bis-GMA or in addition to it in dental resins. Such dimethacrylates based on bisphenol A with various chain lengths are bis-MA 2,2- fs(4-(metha-cryloxy)phenyl)-propane, bis-EMA 2,2-i7is(4-(2-met-hacryloxyethoxy)phenyl)-propane and bis-PMA 2,2- s(4-(3-methacryloxypropoxy)phenyl)-propane. 

The aliphatic urethane acrylates are more potent sensitizers than the aromatic ones, while the aliphatic urethane methacrylates commonly used in dental resins are weak sensitizers (Nethercott et al. 1982 Bjorkner 1984a). 

Munksgaard EC (1992) Permeability of protective gloves to (di)methacrylates in resinous dental materials. Scand J Dent Res 100 189... 

Every branch of dentistry depends on natural or synthetic polymeric materials in some form for successful therapy. The most extensively used but not the oldest group of polymers are the acrylic resins - the methyl methacrylates and derivatives. In fact, when one thinks of dental resins, the acrylics almost exclusively come to mind as though dental polymers were equated with the acrylics. 

The feasibility of using prepolymer monomers as the major component of dental resin systems has recently been demonstrated (31). Highly fluorinated acrylate and methacrylate comb type prepolymer monomers were synthesized from a polyfluorinated oligoether-ol as shown in Figs. 9 and 10. These novel monomers are viscous liquids similar to BIS-GMA but of much larger bulk (MW > 10,000) which should minimize pol mierization shrinkage and improve marginal adaptation. 

Medicine. The polymethacrylates have been used for many years in the manufacture of dentures, teeth, denture bases, and filling materials (116,117) (see Dental materials). In the orthodontics market, methacrylates have found acceptance as sealants, or pit and fissure resin sealants which are painted over teeth and act as a barrier to tooth decay. The dimensional behavior of curing bone-cement masses has been reported (118), as has the characterization of the microstmcture of a cold-cured acryUc resin (119). Polymethacrylates are used to prepare both soft and hard contact lenses (120,121). Hydrogels based on 2-hydroxyethyl methacrylate are used in soft contact lenses and other biomedical appHcations (122,123) (see Contactlenses). 

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. 

The majority of resins are composed of two dimethacrylate monomers, 2,2 -bis [4(2-hydroxy-3-methacryloyloxypropyloxy)phenyl] propane (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) [22-28]. Typically, TEGDMA or other methacrylate monomers are added as viscosity modifiers to Bis-GMA to make the solution less viscous and more appropriate for clinical use. These diluents also allow for better distribution of the components during manufacture of these composite systems. Another common monomer used to make dental composites, especially those manufactured in Europe, is urethane dimethacrylate [24,29, 30], Ethoxy bisphenol A dimethacrylate is another modification of the Bis-GMA monomer that can be used to make a more hydrophobic polymer that would better withstand the wet oral environment. Other diluents include low viscosity diacrylates and dimethacrylates. Table 1 lists some of these monomers [31-37]. 

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