title: Water sorption, solubility, and resultant change in strength among three resin-based dental composites.
abstract: OBJECTIVE
  To determine the water sorption, solubility, and resultant change in strength of one microhybrid and two nanofilled resin-based composites (RBCs).
  
  
  METHODS
  Water sorption, solubility, and three-point bending strength (TPBS) characteristics of a microhybrid RBC Filtek(™) Z250 (Z250; batch 8MA; shade A3) and two nanofilled RBCs, namely Filtek(™) Supreme XT "body" (FSB; batch 8NU; shade A3) and "translucent" shades (FST; batch 6C; shade YT) (3M ESPE Dental Products, St Paul, MN, USA) were investigated following 1 and 13 weeks storage regimes.
  
  
  RESULTS
  FSB displayed a significant increase in water sorption compared with Z250 and FST (P < 0.001), however, the latter demonstrated no significant difference between them following 1 week and 13 weeks immersion periods (P > 0.001). Following the 13-week immersion period, FSB showed greater water solubility compared with Z250 and FST (P < 0.001). FSB exhibited greater TPBS compared with FST in dry control specimens (P < 0.05), but no significant difference among TPBS of all RBCs was identified following the 1-week immersion period (P = 0.290). The TPBS of FSB decreased significantly compared with Z250 and FST following the 13-week immersion period (P < 0.001).
  
  
  CONCLUSIONS
  Since the FSB exhibited greater water sorption, solubility, and resulting strength degradation compared with Z250 and FST, a poor clinical performance may be expected.
authors.affiliation: Science of Dental Materials Department, Institute of Dentistry, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan.
authors.forename: Naresh
authors.initials: N
authors.lastname: Kumar
authors.forename: Laila
authors.initials: L
authors.lastname: Sangi
mesh_terms: D065966:Absorption, Physicochemical; D000327:Adsorption; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D018583:Pliability; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D012995:Solubility; D013314:Stress, Mechanical; D013997:Time Factors; D014867:Water / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C474035:Filtek Supreme; C500649:Filtek Supreme Translucent; C444701:Filtek Z250; D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; D014867:Water; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; C041979:2,2-bis-(4-(2-methacryloxyethoxy)phenyl)propane; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; D015040:Zirconium; C028541:zirconium oxide