title: Effect of ethyl-alpha-hydroxymethylacrylate on selected properties of copolymers and ACP resin composites.
abstract: There is an increased interest in the development of bioactive polymeric dental composites and related materials that have potential for mineralized tissue regeneration and preservation. This study explores how the substitution of ethyl alpha-hydroxymethylacryate (EHMA) for 2-hydroxyethyl methacrylate (HEMA) in photo-activated 2,2-bis[p-(2'-hydroxy-3'-methacryloxypropoxy)phenyl]propane (Bis-GMA) and Bis-GMA/tri(ethylene glycol) dimethacrylate (TEGDMA) resins affected selected physicochemical properties of the polymers and their amorphous calcium phosphate (ACP) composites. Rate of polymerization and the degree of conversion (DC) of polymers {EHMA (E), HEMA (H), Bis-GMA/EHMA (BE), Bis-GMA/HEMA (BH), Bis-GMA/TEGDMA/EHMA (BTE) and Bis-GMA/TEGDMA/HEMA (BTH)} were assessed by photo-differential scanning calorimetry and Fourier-Transform Infrared (FTIR) spectroscopy. ACP/BTE and ACP/BTH composites were evaluated for DC, biaxial flexure strength (BFS), water sorption (WS) and mineral ion release. Mid-FTIR and near-IR measurements revealed the following order of decreasing DC: [E, H polymers (97.0%)] > [BE copolymer (89.9%)] > [BH copolymer (86.2%)] > [BTE, BTH copolymers (85.5%)] > [ACP/BTH composite (82.6%)] > [ACP/BTE composite (79.3%)]. Compared to HEMA, EHMA did not adversely affect the BFS of its copolymers and/or ACP composites. Lower WS of BTE copolymers and composites (28% and 14%, respectively, compared to the BTH copolymers and composites) only marginal reduced the ion release from ACP/BTE composites compared to ACP/BTH composites. More hydrophobic ACP composites with acceptable ion-releasing properties were developed by substituting the less hydrophilic EHMA for HEMA.
authors.affiliation: Polymers Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8546, USA.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Antonucci
authors.forename: Bruce O
authors.initials: BO
authors.lastname: Fowler
authors.forename: Michael D
authors.initials: MD
authors.lastname: Weir
authors.forename: Drago
authors.initials: D
authors.lastname: Skrtic
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Stansbury
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D018786:Bone Substitutes / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry; D008689:Methacrylates / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D018786:Bone Substitutes; D002130:Calcium Phosphates; D003188:Composite Resins; D003764:Dental Materials; D008689:Methacrylates; D011109:Polymethacrylic Acids; C519480:amorphous calcium phosphate; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate