title: Properties of experimental urethane dimethacrylate-based dental resin composite blocks obtained via thermo-polymerization under high pressure.
abstract: OBJECTIVE
  The aim of this study was to use high-pressure high-temperature (HP/HT) polymerization to produce urethane dimethacrylate (UDMA)-triethylene glycol dimethacrylate (TEGDMA) based resin composite blocks (RCB) suitable for dental computer-aided design/manufacture (CAD/CAM) applications and to compare their physical/mechanical properties to those of a commercial dental RCB. The null hypotheses tested were: (1) there are no differences in the physical/mechanical properties between HP/HT polymerized UDMA-TEGDMA RCB and a commercial RCB; (2) volume fraction filler (Vf) does not affect the physical/mechanical properties of HP/HT polymerized RCB.
  
  
  METHODS
  Four UDMA-based experimental RCB were manufactured under HP/HT conditions. A RCB manufactured under the same HP/HT conditions from a commercial resin composite (Z100) and its commercial counterpart CAD/CAM RCB (Paradigm MZ100) were used as controls. Flexural strength (σf), fracture toughness (KIC), and hardness were determined. The results were analyzed using one-way ANOVA, Scheffé multiple means comparisons (α=0.05), and Weibull statistics (for σf). Scanning electron microscopy was used to characterize fractured surfaces.
  
  
  RESULTS
  All HP/HT polymerized RCB had superior σf, KIC, and Weibull modulus compared to the commercial dental RCB. The experimental RCB had similar or superior properties compared to HP/HT polymerized Z100 RCB. Fewer and smaller porosities (not quantified) were apparent in HP/HT polymerized RCB. The experimental RCB that contained 65% Vf showed higher porosity, suggesting practical difficulties in filler incorporation beyond a certain Vf.
  
  
  CONCLUSIONS
  The results of this study suggested that RCB suitable for dental CAD/CAM applications could be obtained by HP/HT polymerization of resin composites based on pure UDMA.
authors.affiliation: Unité de Recherches Biomatériaux Innovants et Interfaces (URB2I-EA4462), Faculté de chirurgie dentaire, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Nguyen
authors.forename: Véronique
authors.initials: V
authors.lastname: Migonney
authors.forename: N Dorin
authors.initials: ND
authors.lastname: Ruse
authors.forename: Michaël
authors.initials: M
authors.lastname: Sadoun
mesh_terms: D000180:Acrylic Resins / Q000138:chemical synthesis*; D000704:Analysis of Variance; D003188:Composite Resins / Q000138:chemical synthesis*; D017076:Computer-Aided Design / Q000295:instrumentation*; D055119:Elastic Modulus; D006244:Hardness; D006358:Hot Temperature; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011092:Polyethylene Glycols / Q000737:chemistry*; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry*; D011140:Polyurethanes / Q000138:chemical synthesis* / Q000737:chemistry*; D011312:Pressure
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols