title: The use of reinforced composite resin cement as compensation for reduced post length.
abstract: BACKGROUND
  Cements that yield high retentive values are believed to allow use of shorter posts.
  
  
  OBJECTIVE
  This study investigated the use of reinforced composite resin cement as compensation for reduced dowel length.
  
  
  METHODS
  The retention values of stainless steel posts (parallel-sided ParaPost and tapered Dentatus in 5-, 8-, and 10-mm lengths) luted with Flexi-Flow titanium-reinforced composite resin and zinc phosphate cements were evaluated. Single-rooted extracted human teeth with crowns (n = 120), removed at the cementoenamel junction, were randomly divided into 4 groups of 30 samples each. Different post lengths were luted with either Flexi-Flow or zinc phosphate. Each sample was placed into a specialized jig and on a tensile testing machine with a crosshead speed of 2 mm/min, applied until failure. The effect of different posts and cements on the force required to dislodge the dowels was evaluated with multiple analyses of variance (ANOVA). One-way ANOVA with Scheffé contrast was applied to determine the effect of different post lengths on the retentive failure of posts luted with the 2 agents.
  
  
  RESULTS
  Flexi-Flow reinforced composite resin cement significantly increased retention of ParaPost and Dentatus dowels (P<.001) compared with zinc phosphate. One-way ANOVA revealed no statistically significant difference (P>.05) between mean retention of both dowels luted with Flexi-Flow for all posts length used (5 mm = 8 mm = 10 mm). Mean retention values of the groups luted with zinc phosphate showed a statistically significant difference (P<.001) for the different post lengths (10 > 8 > 5 mm). Parallel-sided ParaPost dowels demonstrated a higher mean retention than tapered Dentatus dowels (P<.001).
  
  
  CONCLUSIONS
  In this study, Flexi-Flow reinforced composite resin cement compensated for the reduced length of shorter parallel-sided ParaPost and tapered Dentatus dowels.
authors.affiliation: Department of Prosthetic Dentistry, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel. nissandr@post.tau.ac.il
authors.forename: J
authors.initials: J
authors.lastname: Nissan
authors.forename: Y
authors.initials: Y
authors.lastname: Dmitry
authors.forename: D
authors.initials: D
authors.lastname: Assif
mesh_terms: D000704:Analysis of Variance; D002484:Cementation; D003188:Composite Resins / Q000737:chemistry*; D003738:Dental Cements / Q000737:chemistry; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D019232:Dental Restoration Failure; D006801:Humans; D015999:Multivariate Analysis; D011176:Post and Core Technique / Q000295:instrumentation*; D019279:Resin Cements / Q000737:chemistry*; D013193:Stainless Steel / Q000737:chemistry; D013223:Statistics as Topic; D013499:Surface Properties; D013718:Tensile Strength; D014025:Titanium / Q000737:chemistry; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D003188:Composite Resins; D003738:Dental Cements; C101035:Flexi-Flow cement; D019279:Resin Cements; D013193:Stainless Steel; D015036:Zinc Phosphate Cement; D014025:Titanium