title: An investigation of the interfacial strengths of methacrylate resin-based glass fiber post-core buildups.
abstract: OBJECTIVE
  To assess the microtensile bond strengths of a core composite with two different viscosities, MultiCore Flow (F) and Heavy Body (HB) (Ivoclar-Vivadent), on dentin and glass-fiber posts with methacrylate resin matrices, in combination with three dentin adhesives: Syntac Classic (S), Excite DSC (E), and AdheSE (A) (Ivoclar-Vivadent). The omission of an intermediate adhesive coating on silanized posts was also examined to see if this resulted in post-core bond strength reduction.
  
  
  METHODS
  Six experimental dentin and 6 experimental post groups were formed with different core material viscosity/adhesive combinations. In two control post groups, no adhesive was applied on the silanized posts. The core material was stratified on deep dentin or on the posts. From the built-up teeth and the post-core units, microtensile sticks were obtained.
  
  
  RESULTS
  The bond strengths measured on dentin were (MPa): S-F 12.7 +/- 6.4; S-HB 18.3 +/- 7.6; E-F 33.1 +/- 13.7; E-HB 34.1 +/- 10.2; A-F 33.5 +/- 14.8; A-HB 35.5 +/- 14.4. The post-core strengths were: S-F 9.4 +/- 2.5; S-HB 7.1 +/- 3.8; E-F 8.6 +/- 3.8; E-HB 8.1 +/- 4.4; A-F 8.1 +/- 2.7; A-HB 8.3 +/- 2.4; no adhesive-F 10.4 +/- 3.6; no adhesive-HB 6.3 +/- 2.7. Significantly higher interfacial strengths were achieved on dentin than on posts (p < 0.05). Adhesive type significantly affected core-dentin adhesion, with Excite DSC and AdheSE outperforming Syntac Classic (p < 0.05). Neither core material viscosity nor adhesive type significantly influenced post-core adhesion (p > 0.05). Omission of an intermediate adhesive layer had no effect on post-core adhesion (p > 0.05).
  
  
  CONCLUSIONS
  Even after post surface silanization, the bond established by the composite core material with the post remains weaker than that created with coronal dentin.
authors.affiliation: Department of Restorative Dentistry and Dental Materials, University of Siena, Policlinico Le Scotte, Siena, Italy. ferrarimar@unisi.it
authors.forename: Marco
authors.initials: M
authors.lastname: Ferrari
authors.forename: Cecilia
authors.initials: C
authors.lastname: Goracci
authors.forename: Fernanda T
authors.initials: FT
authors.lastname: Sadek
authors.forename: Francesca
authors.initials: F
authors.lastname: Monticelli
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D003804:Dentin / Q000737:chemistry; D006801:Humans; D011140:Polyurethanes / Q000737:chemistry*; D011176:Post and Core Technique; D018709:Statistics, Nonparametric; D013718:Tensile Strength
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D011140:Polyurethanes