title: Pull-out retentive strength of fiber posts cemented at different times in canals obturated with a eugenol-based sealer.
abstract: BACKGROUND
  Currently, no standard luting protocol exists for fiber posts. In addition, no agreement has been reached on the time interval between canal obturation and post space preparation and cementation.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to evaluate the retention of fiber posts cemented with 3 different types of cement: Paracore, Variolink II, and RelyX Unicem cement after 24 hours or 2 weeks in root canals obturated with gutta percha and a eugenol-based sealer.
  
  
  METHODS
  Seventy-two caries-free, freshly extracted, single-rooted human mandibular first premolar teeth with straight root canals were prepared and obturated with gutta percha and Endofil sealer. Specimens were divided into 2 groups (n=36): post spaces prepared 24 hours after obturation and post spaces prepared 2 weeks after obturation. Posts in both groups were luted with 1 of 3 different luting agents (n=12), ParaCore, Variolink II, or RelyX Unicem cement. Each tooth specimen was vertically secured in a universal testing machine, and a constant pull-out loading rate of 0.5 mm/min was applied until cement failure occurred. Data were statistically analyzed with 2-way and 1-way ANOVAs and t tests.
  
  
  RESULTS
  Two-way ANOVA indicated statistically significant differences in mean post retention among the 3 cement types (P<.001) and among the means of the different time intervals investigated (P<.001). Significant differences were noted among all cement types tested between the 24-hour and 2-week time intervals (P<.05).
  
  
  CONCLUSIONS
  Time elapsed between canal obturation and post cementation significantly influenced fiber post retention, regardless of the type of resin cement. Fiber posts showed significantly higher retention if cemented after 24 hours of obturation than if cementation occurred after 2 weeks.
authors.affiliation: Professor, Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia. Electronic address: drimplant_prostho@yahoo.com.
authors.forename: Khalil
authors.initials: K
authors.lastname: Aleisa
authors.affiliation: Professor, Department of Prosthodontics, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan.
authors.forename: Ziad Nawaf
authors.initials: ZN
authors.lastname: Al-Dwairi
authors.affiliation: Assistant Professor, Division of Endodontic Dentistry, Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Sara A
authors.initials: SA
authors.lastname: Alsubait
authors.affiliation: Professor, Department of Restorative Dentistry, Rutgers School of Dental Medicine, Newark, NJ.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Morgano
mesh_terms: D002484:Cementation / Q000379:methods*; D017268:Dental Prosthesis Retention / Q000379:methods; D003799:Dental Stress Analysis; D005054:Eugenol / Q000627:therapeutic use*; D006801:Humans; D066298:In Vitro Techniques; D010895:Pit and Fissure Sealants / Q000627:therapeutic use*; D011176:Post and Core Technique; D012389:Root Canal Obturation / Q000379:methods*; D013997:Time Factors
chemical_list: D010895:Pit and Fissure Sealants; D005054:Eugenol