title: Effect of irradiation time on tensile properties of stiffness and strength of composites.
abstract: OBJECTIVE
  We compared the effect of irradiation time on the diametral tensile strength and stiffness of three visible light-cured composites. The sensitivity of the two mechanical properties to differentiate between the materials was also investigated.
  
  
  METHODS
  Cylindrical specimens of three composites were cured for 20, 40, 80, and 120 seconds (n = 10) and loaded up to failure in a diametral tensile strength test. Stiffness and diametral tensile strength values were recorded.
  
  
  RESULTS
  Irradiation time significantly influenced diametral tensile strength (p = 0.0017) and stiffness (p = 0.0002). With the same irradiation times the three tested materials demonstrated no significant difference when diametral tensile strength was studied (p = 0.31). However, stiffness values did show a significant difference (p = 0.0002).
  
  
  CONCLUSIONS
  This study found that stiffness is more sensitive in disclosing differences in tensile properties between the materials than diametral tensile strength.
authors.affiliation: Section of Oral Rehabilitation, Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel.
authors.forename: H
authors.initials: H
authors.lastname: Baharav
authors.forename: T
authors.initials: T
authors.lastname: Brosh
authors.forename: R
authors.initials: R
authors.lastname: Pilo
authors.forename: H
authors.initials: H
authors.lastname: Cardash
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry / Q000528:radiation effects; D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects*; D003764:Dental Materials / Q000737:chemistry / Q000528:radiation effects; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents / Q000737:chemistry / Q000528:radiation effects; D004548:Elasticity / Q000528:radiation effects; D008027:Light; D008422:Materials Testing; D011829:Radiation Dosage; D019279:Resin Cements / Q000737:chemistry / Q000528:radiation effects; D013314:Stress, Mechanical; D013718:Tensile Strength / Q000528:radiation effects; D013997:Time Factors
chemical_list: C069351:Brilliant Direct-Inlay resin; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D019279:Resin Cements; C065770:Herculite XR; C065771:P50 composite resin; D017438:Bisphenol A-Glycidyl Methacrylate