title: Diametral tensile strength of dual-curing resin cements submitted exclusively to autopolymerization.
abstract: OBJECTIVE
  To evaluate, at different times, the diametral tensile strength (DTS) of dual-curing resin cements that were not photopolymerized.
  
  
  METHODS
  Equal amounts of base and catalyst pastes of Panavia F (Kuraray), Variolink II (Vivadent), Rely X (3M ESPE), and Enforce (Dentsply) were mixed and inserted into cylindrical molds (4 x 2 mm) (n = 10). Cements were not photopolymerized. DTS test was performed in a testing machine at 30 minutes, 1 hour, 24 hours, and 7 days. The specimens were stored in light-proof containers with distilled water at 37 degrees C until the time of assay. An autopolymerizing resin cement (Cement-It, Jeneric Pentron) and a zinc phosphate cement served as controls. One-way analysis of variance (ANOVA) and Tukey test were performed separately for each cement and for each time (P <.05).
  
  
  RESULTS
  All cements showed an increase in DTS when tested at 1 and 24 hours. Tests at 24 hours and 7 days revealed no statistically significant differences. In all groups, the zinc phosphate cement had the lowest DTS mean values (2.1 MPa, 3.6 MPa, 6.5 MPa, and 6.9 MPa), while Cement-It (35.1 MPa, 33.6 MPa, 46.9 MPa, and 46.3 MPa) and Enforce (31.9 MPa, 31.7 MPa, 43.4 MPa, and 47.6 MPa) presented the highest DTS mean values.
  
  
  CONCLUSIONS
  All cements presented maximal strength at 24 hours. The dual-curing resin cements, even when nonphotopolymerized, demonstrated higher DTS than the zinc phosphate cement and similar or lower values than the autopolymerizing resin cement.
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara Dental School, São Paulo State University, Brazil. renata@foar.unesp.br
authors.forename: Renata Garcia
authors.initials: RG
authors.lastname: Fonseca
authors.forename: Thais Paci
authors.initials: TP
authors.lastname: Artusi
authors.forename: Juliana Gomes
authors.initials: JG
authors.lastname: dos Santos
authors.forename: Gelson Luis
authors.initials: GL
authors.lastname: Adabo
mesh_terms: D000704:Analysis of Variance; D001840:Dental Bonding; D003799:Dental Stress Analysis; D044367:Phase Transition; D019279:Resin Cements / Q000737:chemistry; D018709:Statistics, Nonparametric; D013718:Tensile Strength; D013997:Time Factors
chemical_list: D019279:Resin Cements