title: Micro push-out bond strengths of four fiber-reinforced composite post systems and 2 luting materials.
abstract: OBJECTIVE
  The aim of this study was to compare the bond strengths of 2 types of dual-cured luting agents used for cementation of 4 different fiber-reinforced composite (FRC) posts by using a push-out test and to evaluate the failure modes of these systems.
  
  
  METHODS
  Eighty human maxillary central incisors were divided into 8 groups (n = 10), decoronated, and roots filled and restored with one of the following post systems: groups 1 to 4: translucent quartz FRC posts; groups 5 and 6: opaque glass FRC post; and groups 7 and 8: individually formed electrical glass fiber post. Cementation was performed with 2 types of dual-polymerizing resin luting agents: Variolink II (groups 1, 3, 5, and 7) and a new self-adhesive resin cement, RelyX Unicem (groups 2, 4, 6, and 8). Slices with a thickness of 1.00 +/- 0.05 mm were prepared from the coronal third of each root by using a low-speed saw. Push-out tests were performed at a crosshead speed of 1 mm/min by using a universal testing machine, and the data was statistically analyzed (analysis of variance [ANOVA] and Duncan tests; P < .05). Fracture modes were evaluated at original magnification x40.
  
  
  RESULTS
  Micro push-out bond strengths were significantly affected by the type of luting agent and the type of post (P < .05, 2-way ANOVA). A significant difference was found among the groups (1-way ANOVA, P < .05). Fiber-reinforced composite posts luted with Variolink II showed higher bond strengths, and the groups ordered as 5, 1, 3, 7, 6, 2, 4, and 8, with the values (MPa, mean +/- SD): 13.80 +/- 5.00, 13.77 +/- 3.78, 12.20 +/- 4.79, 9.39 +/- 2.48, 9.21 +/- 7.76, 7.25 +/- 1.56, 3.89 +/- 4.41, and 3.77 +/- 1.20, respectively. Adhesive failures between dentin and cement were observed more than cohesive failures in cement or post.
  
  
  CONCLUSIONS
  Push-out bond strengths can be affected by luting agent and post type. Variolink II and fiber post combinations resulted in high bond strength values.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Suleyman Demirel University, Isparta, Turkey. diljink@med.sdu.edu.tr
authors.forename: Ayse D
authors.initials: AD
authors.lastname: Kececi
authors.forename: B
authors.initials: B
authors.lastname: Ureyen Kaya
authors.forename: Necdet
authors.initials: N
authors.lastname: Adanir
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing / Q000379:methods; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry*; D012390:Root Canal Therapy / Q000295:instrumentation / Q000379:methods*
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; D005899:Glass Ionomer Cements; D019279:Resin Cements; C084550:Vitremer; C103502:Variolink