title: Shear resistance of fiber-reinforced composite and metal dentin pins.
abstract: OBJECTIVE
  To assess whether dentin pins increase shear resistance of extensive composite restorations and to compare performance of mini fiber-reinforced composite (FRC) anchors with metal dentin pins in the laboratory.
  
  
  METHODS
  30 extracted sound molars were randomly divided into three groups. Occlusal surfaces were ground flat with a standard surface area and resin composite restorations were made in Group A. In Groups B and C similar restorations were made, with additionally four metal pins placed in Group B and four FRC pins in Group C. Specimens were statically loaded until failure occurred. Failure modes were characterized as intact remaining tooth substrate (adhesive or cohesive failure of restoration) or fractured remaining tooth substrate.
  
  
  RESULTS
  Mean failure stresses were 6.5 MPa (SD 3.2 MPa) for Group A, 9.7 MPa (SD 2.6 MPa) for Group B and 9.2 MPa (SD 2.6 MPa) for Group C. Difference in mean failure stresses between Group A and Groups B and C was statistically significant (P = 0.01), while the difference between Groups B and C was not (P = 0.63). Failures of the restoration without fracture of tooth substrate were seen for 80% of specimens in Group A and 20% in Groups B and C (P = 0.04).
authors.affiliation: Department of Oral-Maxillofacial Surgery, Prosthodontics and Special Dental Care, University Medical Centre Utrecht, P.O. Box 85500, 3508 GA Utrecht, The Netherlands. w.m.m.fennis-2@umcutrecht.nl
authors.forename: Willem M M
authors.initials: WM
authors.lastname: Fennis
authors.forename: Joop G C
authors.initials: JG
authors.lastname: Wolke
authors.forename: Camilo
authors.initials: C
authors.lastname: Machado
authors.forename: Nico H J
authors.initials: NH
authors.lastname: Creugers
authors.forename: Cees M
authors.initials: CM
authors.lastname: Kreulen
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000268:Adhesiveness; D000636:Aminosalicylic Acids / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003772:Dental Pins; D003793:Dental Restoration, Permanent / Q000295:instrumentation / Q000379:methods; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D005898:Glass / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D013314:Stress, Mechanical; D019246:Tooth Preparation / Q000379:methods
chemical_list: D000636:Aminosalicylic Acids; D003188:Composite Resins; D003722:Dental Alloys; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C500742:ED Primer II; D008689:Methacrylates; C438843:Panavia-Fluoro; D010756:Phosphoric Acids; D019279:Resin Cements; C009753:fiberglass; C074669:Clearfil Photo Bond; C092420:Clearfil Photo Posterior; C074497:N-methacryloyl-5-aminosalicylic acid; C030242:phosphoric acid