title: Retention of three endodontic posts cemented with five dental cements.
abstract: BACKGROUND
  The retention of a post is believed to be a major factor in restoration survival. Therefore the cement with the greatest in vitro retention property should give the best performance for a restoration.
  
  
  OBJECTIVE
  This study compared retentive values of three posts (Flexi-Post, AccessPost, and ParaPost) cemented with five cements (Flexi-Flow, zinc phosphate, Advance, Duet, and Ketac-Cem) plus a control group that consisted of a Flexi-Post No. 2 dowel without cement.
  
  
  METHODS
  A total of 160 recently extracted human single-rooted teeth with crowns removed at the cementoenamel junction were divided into 16 groups of 10 samples. Post holes were prepared according to manufacturers' instructions. Posts were then cemented with one of the five cements. Each sample was placed into a specialized jig and on a tensile testing machine with crosshead speed of 0.638 cm/minute, applied until failure. A two-way analysis of variance and Newman-Keuls multiple range comparison tests were performed for all cemented groups. A one-way analysis of variance and a Student-Newman-Keuls multiple range comparison test were performed only for the groups with the Flexi-Post dowel, this included the no cement condition, with significant results if p < 0.05.
  
  
  RESULTS
  Flexi-Post dowel with Flexi-Flow Natural cement obtained the highest retentive value (303.91 pounds). ParaPost dowel with Duet cement exhibited the lowest retention value (21.23 pounds). The Flexi-Post dowel demonstrated higher mean retention than AccessPost or ParaPost dowels, AccessPost dowel was higher than ParaPost dowel. Flexi-Flow cement had the highest overall mean retention followed, in decreasing order, by zinc phosphate, Advance, Ketac-Cem, and Duet cements.
  
  
  CONCLUSIONS
  Flexi-Post dowel was the most retentive post studied with values ranging from 303.91 pounds with Flexi-Flow Natural cements to 150.93 pounds without cement. Flexi-Flow cements had a higher overall mean retention than other cements studied.
authors.affiliation: Essential Dental Laboratories, South Hackensack, N.J., USA.
authors.forename: B I
authors.initials: BI
authors.lastname: Cohen
authors.forename: M K
authors.initials: MK
authors.lastname: Pagnillo
authors.forename: I
authors.initials: I
authors.lastname: Newman
authors.forename: B L
authors.initials: BL
authors.lastname: Musikant
authors.forename: A S
authors.initials: AS
authors.lastname: Deutsch
mesh_terms: D000704:Analysis of Variance; D002484:Cementation / Q000379:methods*; D003188:Composite Resins; D003738:Dental Cements; D017268:Dental Prosthesis Retention; D005899:Glass Ionomer Cements; D006801:Humans; D008277:Magnesium Oxide; D008422:Materials Testing; D011076:Polycarboxylate Cement; D011176:Post and Core Technique; D019279:Resin Cements; D018709:Statistics, Nonparametric; D015034:Zinc Oxide; D015036:Zinc Phosphate Cement
chemical_list: C094366:Advance cement; D003188:Composite Resins; D003738:Dental Cements; C094367:Duet cement; C061504:Flecks; C101035:Flexi-Flow cement; D005899:Glass Ionomer Cements; D011076:Polycarboxylate Cement; D019279:Resin Cements; D008277:Magnesium Oxide; D015036:Zinc Phosphate Cement; C040235:Ketac-cem; D015034:Zinc Oxide