title: Retention of prefabricated and individually cast root canal posts in vitro.
abstract: OBJECTIVE
  The aim of the study was to evaluate the retention of prefabricated root canal posts made of a variety of materials that have recently been introduced into dentistry.
  
  
  METHODS
  The posts studied were CosmoPost, Composipost carbon fibres, Composipost Aestheti-Plus, Composipost Light-Post and Para Post Fiber White. The posts were luted in extracted human premolars and the cores were built up with the resin composites recommended by the manufacturers. The retention of individually cast gold alloy posts luted with zinc-phosphate cement were used as reference. A universal testing machine was used to determine the retention of each cemented post Data were compared using ANOVA supplemented with Fisher's PLSD at a significance level of p < 0.05.
  
  
  RESULTS
  Only the CosmoPost system exhibited retention values that were significantly lower than for the conventionally cast gold alloy posts luted with zinc-phosphate cement The force necessary to loosen the CosmoPost specimens was significantly less than that needed to loosen the Composipost. Estheti-Plus (p < 0.05) and the Composipost Ught-Post systems (p < 0.001]. The force necessary to loosen the ParaPost Fiber White specimens was significantly less than for the Composipost Light-Post system (p < 0.01). Other combinations did not differ significantly (p > 0.05).
  
  
  CONCLUSIONS
  When zirconium oxide ceramic posts are luted with resin composites the bonding between the ceramic and resin composite seems to be weak. Further studies are thus necessary to achieve improved retention of all-ceramic root canal posts.
authors.affiliation: Department of Dental Materials Science, Faculty of Medicine and Odontology, Umeå University, SE-901 87 Umeå, Sweden. Sven-Olof.Hedlund@odont.umu.se
authors.forename: S-O
authors.initials: SO
authors.lastname: Hedlund
authors.forename: N G
authors.initials: NG
authors.lastname: Johansson
authors.forename: G
authors.initials: G
authors.lastname: Sjögren
mesh_terms: D000704:Analysis of Variance; D001641:Bicuspid; D002244:Carbon / Q000737:chemistry; D000077482:Carbon Fiber; D002484:Cementation; D002516:Ceramics / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D011176:Post and Core Technique / Q000295:instrumentation*; D011791:Quartz / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D015036:Zinc Phosphate Cement / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry
chemical_list: D000077482:Carbon Fiber; D003188:Composite Resins; D003764:Dental Materials; D006047:Gold Alloys; D019279:Resin Cements; C078484:Syntac dentine adhesive; D011791:Quartz; C103502:Variolink; D002244:Carbon; D015036:Zinc Phosphate Cement; D015040:Zirconium; C028541:zirconium oxide