title: The mechanical stability of nano-hybrid composites with new methacrylate monomers for matrix compositions.
abstract: OBJECTIVE
  Dimer acid based metacrylates and TCD-urethane are promoted as new monomers of nano-hybrid resin based composites as alternatives for the conventional BisGMA. Investigations of this study focused on the mechanical and the storage behavior of nano-hybrid resin based composites (RBCs) composed of these new types of monomers in comparison to RBCs using BisGMA.
  
  
  METHODS
  Flexural strength and modulus were determined in a three-point-bending test. Additionally, the modulus of elasticity was measured on microscopic scale (E(micro)) using an automatic microhardness indenter. Tests were performed on samples after 24 h storage in distilled water, as well as after thermocycling and storing the materials for four weeks in either distilled water, artificial saliva or ethanol.
  
  
  RESULTS
  The six measured materials showed a pronounced decrease of flexural strength, flexural modulus and E(micro) after four weeks storage in alcohol. Results after four weeks storage in water and saliva could not be proven to be significantly different. The most sensitive factor of influence on all test parameters was the material.
  
  
  CONCLUSIONS
  Nano-hybrid composites with new or conventional monomers performed similar in regard to the mechanical properties and the behavior of the materials after aging.
authors.affiliation: Department of Restorative Dentistry, Dental School of the Ludwig-Maximilians-University, Goethestr. 70, 80336 Munich, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Schmidt
authors.forename: Nicoleta
authors.initials: N
authors.lastname: Ilie
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D055119:Elastic Modulus; D000431:Ethanol / Q000737:chemistry; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D055595:Mechanical Phenomena; D008689:Methacrylates / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D018583:Pliability; D012464:Saliva, Artificial / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C509998:Grandio; D008689:Methacrylates; C551012:N'Durance composite resin; D012464:Saliva, Artificial; C510232:Simile composite resin; D012997:Solvents; C488393:Venus (composite resin); C507210:premise composite resin; D014867:Water; D000431:Ethanol; D017438:Bisphenol A-Glycidyl Methacrylate