title: Physical and mechanical properties of an experimental dental composite based on a new monomer.
abstract: OBJECTIVE
  The purpose of this study was to investigate the physical and mechanical properties of a dental composite based on BTDMA, a new dimethacrylate monomer based on BTDA (3,3',4,4'-benzophenone tetracarboxylic dianhydride), and to compare these with the properties of a composite based on commonly used Bis-GMA monomer.
  
  
  METHODS
  Experimental composites were prepared by mixing the silane-treated filler with the monomers. The prepared pastes were inserted into the test molds and heat-cured. Light-cured composites were also prepared using camphorquinone and amine as photoinitiator system. Degree of conversion of the light-cured and heat-cured composites was measured using FTIR spectroscopy. The flexural strength, flexural modulus, diametral tensile strength (DTS), water sorption, water contact angle, microhardness and thermal expansion coefficient of the prepared composites were measured and compared. Water uptake of the monomers was also measured.
  
  
  RESULTS
  The results showed that the mechanical properties of the new composite are comparable with the properties of the Bis-GMA-based composite but its water sorption is higher. BTDMA as a monomer containing aromatic rings and carboxylic acid groups in its structure gives a composite with good mechanical properties. There is a close relation between the contact angle, water sorption of the cured composite and water uptake of their monomers.
  
  
  CONCLUSIONS
  Finding new monomers as alternatives for Bis-GMA have been a challenge in the field of dental materials and any investigation into the properties of new composites would be beneficial in the development of dental materials.
authors.affiliation: Iran Polymer and Petrochemical Institute (IPPI), P.O. Box 14965/115 Tehran, Iran. m.atai@ippi.ac.ir
authors.forename: M
authors.initials: M
authors.lastname: Atai
authors.forename: M
authors.initials: M
authors.lastname: Nekoomanesh
authors.forename: S A
authors.initials: SA
authors.lastname: Hashemi
authors.forename: S
authors.initials: S
authors.lastname: Amani
mesh_terms: D000704:Analysis of Variance; D001577:Benzophenones / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins / Q000737:chemistry*; D003799:Dental Stress Analysis; D004548:Elasticity; D006244:Hardness; D006358:Hot Temperature; D008027:Light; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D044367:Phase Transition; D018583:Pliability; D018709:Statistics, Nonparametric; D013718:Tensile Strength; D017155:Wettability
chemical_list: D001577:Benzophenones; D003188:Composite Resins; D008689:Methacrylates; C044290:benzophenone-3,3',4,4'-tetracarboxylic acid; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate