title: e-Modulus of resin cements as a function of curing source and storage time.
abstract: OBJECTIVE
  The aim of this study was to evaluate the e-modulus of two resin cements, with different curing sources and storage times, by flexural strength.
  
  
  METHODS
  Ninety-six rectangular specimens were prepared from 2 dual-cured resin cements (Bistite II DC and Panavia F 2.0). A QTH light-curing unit (XL 3000) and a light-emitting diode (Optilight CL) were used for curing. The specimens were stored for 24 hours or 30 days. Testing consisted of three-point flexural strength, with 50 kg of load and crosshead speed of 0.5 mm/min. Data were analyzed with analysis of variance and Tukey test (5%).
  
  
  RESULTS
  When QTH light curing was used, Panavia had flexural strengths of 183.30 MPa at 24h and 112.30 at 30 days; whereas, Bistite had strengths of 160.20 MPA at 24h and 120.20 MPa at 30 days. However, when LED was used, the values were significantly lower for both cements. The main effects of cement type, storage time and curing unit type were statistically significant, as were the statistical interactions of cement/curing unit and time/curing unit.
  
  
  CONCLUSIONS
  The experimental effects of cement type, storage time and curing unit type profoundly affected e-modulus.
authors.affiliation: Department of Restorative Dentistry, Paulista University (UNIP), São Paulo, Brazil.
authors.forename: M
authors.initials: M
authors.lastname: Dutra-Corrêa
authors.forename: L
authors.initials: L
authors.lastname: Alves Cunha
authors.forename: M A M
authors.initials: MA
authors.lastname: De Araújo
authors.forename: M
authors.initials: M
authors.lastname: Carneiro Valera
mesh_terms: D003188:Composite Resins; D055117:Curing Lights, Dental; D019554:Dental Restoration Wear; D004356:Drug Storage; D055119:Elastic Modulus; D019279:Resin Cements; D013997:Time Factors
chemical_list: C096475:Bistite Resin Cement; D003188:Composite Resins; C438843:Panavia-Fluoro; D019279:Resin Cements