title: Mechanical properties of denture base resin cross-linked with methacrylated dendrimer.
abstract: OBJECTIVE
  The aim of this study was to investigate the mechanical properties of denture base resin cross-linked with methacrylated dendrimer.
  
  
  METHODS
  The test specimens (3 mm × 10 mm × 65 mm) were fabricated from autopolymerizing resin with the powder/liquid ratio of 10 g/7 ml. The monomer liquid of resin was applied with the mixture of methylmethacrylate and crosslinker dendrimer (DD1) or crosslinker ethyleneglycol dimethacrylate (EGDMA) with five different volume percentages (vol%). The dendrimer crosslinker in this study is a methacrylated molecule (MW=3617 g/mol) with 12 methacrylate groups. Quantity of crosslinkers varied from 1.1 to 9.1 vol%. The specimens (n=8/group) were polymerized in distilled water maintained at 55 °C under pressure of 0.4 MPa for 20 min. Test specimens were stored dry at room temperature before testing. The flexural strength (MPa) and flexural modulus (GPa) was measured with three-point bending test at a crosshead speed of 5mm/min. Surface microhardness (MHN) of matrix area of polymer (n=8/group) was measured with a load of 245.3 mN by 10s. Data were analyzed with two-way ANOVA.
  
  
  RESULTS
  ANOVA showed that the addition of DD1 had a significantly higher effect (p<0.05) on flexural modulus and hardness of matrix area than EGDMA but on flexural strength (p>0.05). The effect of quantity differences of crosslinker was statistically significant only on flexural strength (p<0.05).
  
  
  CONCLUSIONS
  The results of this study suggest that dendrimer-crosslinked resin gives better stiffness than that of EGDMA.
authors.affiliation: Department of Biomaterials Science, Institute of Dentistry, University of Turku, Turku, Finland. tomokawa@college.fdcnet.ac.jp
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kawaguchi
authors.forename: Lippo V J
authors.initials: LV
authors.lastname: Lassila
authors.forename: Pekka K
authors.initials: PK
authors.lastname: Vallittu
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takahashi
mesh_terms: D000465:Algorithms; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003819:Denture Bases; D055119:Elastic Modulus; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D055595:Mechanical Phenomena; D008689:Methacrylates / Q000737:chemistry*; D020366:Methylmethacrylate / Q000737:chemistry; D018583:Pliability; D011091:Polyesters / Q000737:chemistry; D058105:Polymerization; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011312:Pressure; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D003764:Dental Materials; D008689:Methacrylates; D011091:Polyesters; D014867:Water; D020366:Methylmethacrylate; C004919:ethylene dimethacrylate; D019904:Polymethyl Methacrylate