title: Retention of a core material supported by three post head designs.
abstract: BACKGROUND
  There are few studies on the retention of core build-up materials to prefabricated post head designs, especially for a new ceramic post design.
  
  
  OBJECTIVE
  This in vitro study compared the retention of 2 types of core build-up materials (Ti-Core titanium-reinforced composite and a GC Miracle Mix silver-reinforced glass ionomer) supported by 3 post head designs (Flexi-Post, AccessPost, and Cerapost dowel). For all test groups, heads of the posts were placed into the core material at a 90-degree angle to the surface. Test specimens (unloaded) were then placed into a special jig and retention test was performed using an 810 MTS testing machine.
  
  
  METHODS
  This study consisted of 6 groups with 10 specimens per group. A 3 x 2 factorial design was used to test for statistical significance and results were considered significant when P <.05.
  
  
  RESULTS
  Results of the retention test were as follows: group 1, Flexi-Post/Ti-Core 220.0 lb (982.1 N), group 2, AccessPost/Ti-Core 212.7 lb (949.6 N), group 3, Cerapost/Ti-Core 41. 8 lb (186.6 N), group 4, Flexi-Post/Miracle Mix 43.4 lb (193.8 N), group 5, AccessPost/Miracle Mix 61.6 lb (275 N), and group 6, Cerapost/Miracle Mix 7.5 lb (33.5 N). Results of the ANOVA revealed a highly significant difference between posts and cores (P <.0001).
  
  
  CONCLUSIONS
  Post head designs of the stainless steel AccessPost and Flexi-Post dowels offers greater retention then the smooth ceramic head design of the Cerapost dowel. In addition, the composite core material (Ti-Core) offers greater retentive strength values than the glass ionomer material (Miracle Mix).
authors.affiliation: Essential Dental Laboratories, S Hackensack, NJ, USA. eds@pipeline.com
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; D003764:Dental Materials / Q000737:chemistry; D017267:Dental Prosthesis Design / Q000379:methods* / Q000706:statistics & numerical data; D017268:Dental Prosthesis Retention / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing / Q000379:methods / Q000706:statistics & numerical data; D011176:Post and Core Technique / Q000706:statistics & numerical data
chemical_list: D003764:Dental Materials