title: Performance of the experimental resins and dental nanocomposites at varying deformation rates.
abstract: OBJECTIVE
  The aim of the present study was to evaluate the bi-axial flexural strength of experimental unfilled resins and resin-based composites at varying deformation rates following 1-week dry, 1-week wet, and 13-week wet storage regimes.
  
  
  METHODS
  A total of 270 disc-shaped specimens (12 mm diameter, 1 mm thickness) of either unfilled resins or experimental resin-based composites comprising of three groups (n = 90) were fabricated. Three groups of each unfilled resin and resin-based composites (n = 90) were stored for 1 week under dry conditions, and at 1 and 13 weeks under wet conditions (37 ± 1°C) before testing. The bi-axial flexural strength of each unfilled resin and resin-based composites group was determined at a 0.1, 1, and 10 mm/min deformation rate (n = 30).
  
  
  RESULTS
  The unfilled resins revealed a deformation rate dependence following all storage regimes; however, the addition of fillers in the unfilled resins modified such reliance following the 1-week dry and 13-week wet storage regimes. In contrast, a lower bi-axial flexural strength of the 1-week wet resin-based composites specimens at a 0.1 mm/min deformation rate was identified.
  
  
  CONCLUSIONS
  A lower bi-axial flexural strength of the 1-week wet resin-based composites specimens at a low deformation rate suggests that premature failure of resin-based composites restorations might occur in patients with parafunctional habits, such as bruxism.
authors.affiliation: Department of Science of Dental Materials, Institute of Dentistry, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan.
authors.forename: Naresh
authors.initials: N
authors.lastname: Kumar
authors.forename: Adrian
authors.initials: A
authors.lastname: Shortall
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002164:Camphor / Q000031:analogs & derivatives / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003890:Desiccation; D005898:Glass / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D053761:Nanocomposites / Q000737:chemistry*; D058567:Photoinitiators, Dental / Q000737:chemistry; D018583:Pliability; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019163:Reducing Agents / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry*; D012822:Silicon Dioxide / 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; D008689:Methacrylates; D058567:Photoinitiators, Dental; D011109:Polymethacrylic Acids; D019163:Reducing Agents; D012117:Resins, Synthetic; D014867:Water; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D002164:Camphor; D012822:Silicon Dioxide; C049840:2-(dimethylamino)ethyl methacrylate; C553149:camphorquinone
keywords: bi-axial flexure strength; deformation rate; resin-based composite; storage regime; unfilled resin