title: Effects of curing protocol and storage time on the micro-hardness of resin cements used to lute fiber-reinforced resin posts.
abstract: OBJECTIVE
  To determine the micro-hardness profile of two dual cure resin cements (RelyX-U100, 3M-eSPe and Panavia F 2.0, Kuraray) used for cementing fiberre inforced resin posts (Fibrekor-Jeneric Pentron) under three different curing protocols and two water storage times.
  
  
  METHODS
  Sixty 16 mm long bovine incisor roots were endodontically treated and prepared for cementation of the Fibrekor posts. The cements were mixed as instructed, dispensed in the canal, the posts were seated and the curing performed as follows: (a) no light activation; (b) light-activation immediately after seating the post, and; (c) light-activation delayed 5 minutes after seating the post. The teeth were stored in water and retrieved for analysis after 7 days and 3 months. The roots were longitudinally sectioned and the microhardness was determined at the cervical, middle and apical regions along the cement line. The data was analyzed by the three-way ANOVA test (curing mode, storage time and thirds) for each cement. The Tukey test was used for the post-hoc analysis.
  
  
  RESULTS
  Light-activation resulted in a significant increase in the microhardness. This was more evident for the cervical region and for the Panavia cement. Storage in water for 3 months caused a reduction of the micro-hardness for both cements. The U100 cement showed less variation in the micro-hardness regardless of the curing protocol and storage time.
  
  
  CONCLUSIONS
  The micro-hardness of the cements was affected by the curing and storage variables and were material-dependent.
authors.affiliation: Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil. marcelobr74@yahoo.com.br
authors.forename: Marcelo Barbosa
authors.initials: MB
authors.lastname: Ramos
authors.forename: Thiago Amadei
authors.initials: TA
authors.lastname: Pegoraro
authors.forename: Luiz Fernando
authors.initials: LF
authors.lastname: Pegoraro
authors.forename: Ricardo Marins
authors.initials: RM
authors.lastname: Carvalho
mesh_terms: D000818:Animals; D002417:Cattle; D055117:Curing Lights, Dental; D003738:Dental Cements / Q000737:chemistry* / Q000528:radiation effects; D006245:Hardness Tests; D008422:Materials Testing; D058105:Polymerization; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry* / Q000528:radiation effects; D013499:Surface Properties; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: C095997:DCR cement; D003738:Dental Cements; C438843:Panavia-Fluoro; C528569:Rely-X; D019279:Resin Cements; D014867:Water