title: Analysis of resin-dentin interface morphology and bond strength evaluation of core materials for one stage post-endodontic restorations.
abstract: OBJECTIVE
  Restoration of endodontically treated teeth using fiber posts in a one-stage procedure gains more popularity and aims to create a secondary monoblock. Data of detailed analyses of so called "post-and-core-systems" with respect to morphological characteristics of the resin-dentin interface in combination with bond strength measurements of fiber posts luted with these materials are scarce. The present study aimed to analyze four different post-and-core-systems with two different adhesive approaches (self-etch and etch-and-rinse).
  
  
  METHODS
  Human anterior teeth (n = 80) were endodontically treated and post space preparations and post placement were performed using the following systems: Rebilda Post/Rebilda DC/Futurabond DC (Voco) (RB), Luxapost/Luxacore Z/Luxabond Prebond and Luxabond A+B (DMG) (LC), X Post/Core X Flow/XP Bond and Self Cure Activator (Dentsply DeTrey) (CX), FRC Postec/MultiCore Flow/AdheSE DC (Ivoclar Vivadent) (MC). Adhesive systems and core materials of 10 specimens per group were labeled using fluorescent dyes and resin-dentin interfaces were analyzed using Confocal Laser Scanning Microscopy (CLSM). Bond strengths were evaluated using a push-out test. Data were analyzed using repeated measurement ANOVA and following post-hoc test.
  
  
  RESULTS
  CLSM analyses revealed significant differences between groups with respect to the factors hybrid layer thickness (p<0.0005) and number of resin tags (p = 0.02; ANOVA). Bond strength was significantly affected by core material (p = 0.001), location inside the root canal (p<0.0005) and incorporation of fluorescent dyes (p = 0.036; ANOVA). CX [7.7 (4.4) MPa] demonstrated significantly lower bond strength compared to LC [14.2 (8.7) MPa] and RB [13.3 (3.7) MPa] (p<0.05; Tukey HSD) but did not differ significantly from MC [11.5 (3.5) MPa].
  
  
  CONCLUSIONS
  It can be concluded that bond strengths inside the root canal were not affected by the adhesive approach of the post-and-core-system. All systems demonstrated homogenous hybrid layer formation and penetration into the dentinal tubules in spite of the complicating conditions for adhesion inside the root canal.
authors.affiliation: Department for Operative and Preventive Dentistry, University School of Dental Medicine, CharitéCentrum 3, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Bitter
authors.affiliation: Department for Operative and Preventive Dentistry, University School of Dental Medicine, CharitéCentrum 3, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Christin
authors.initials: C
authors.lastname: Gläser
authors.affiliation: Department of Medical Informatics Biometry and Epidemiology, CharitéCentrum 4, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Konrad
authors.initials: K
authors.lastname: Neumann
authors.affiliation: Department for Operative and Preventive Dentistry, University School of Dental Medicine, CharitéCentrum 3, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Blunck
authors.affiliation: Department of Operative Dentistry and Endodontology, University of Marburg, Marburg, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Frankenberger
mesh_terms: D003804:Dentin / Q000737:chemistry*; D006801:Humans; D066298:In Vitro Techniques; D018613:Microscopy, Confocal; D011446:Prospective Studies; D012117:Resins, Synthetic / Q000737:chemistry*; D019553:Tooth, Nonvital
chemical_list: D012117:Resins, Synthetic