title: Mechanical properties related to the microstructure of seven different fiber reinforced composite posts.
abstract: OBJECTIVE
  The aim of thisin vitrostudy was to evaluate the mechanical properties (bending strength and hardness) of seven different fiber reinforced composite posts, in relation to their microstructural characteristics.
  
  
  METHODS
  Two hundred eighty posts were divided into seven groups of 40, one group for each type of post analyzed. Within each group, 15 posts were subjected to three-point bending strength test, 15 to a microhardess meter for the Knoop hardness, and 10 to Scanning Electron Microscope in order to determine the diameter of the fibers and the percentage of fibers embedded in the matrix. To compare the flexural strength in relation to the type of fiber, matrix, and the hardness of the posts, a Kruskal-Wallis H test was used. The Jonckheere-Terpstra test was used to determine if the volume percent of fibers in the post influenced the bending strength.
  
  
  RESULTS
  The flexural strength and the hardness depended on the type of fibers that formed the post. The lower flexural strength of a post could be due to deficient bonding between the fiber and the resin matrix.
  
  
  CONCLUSIONS
  According to the results, other factors, besides the microstructural characteristics, may also influence the mechanical properties of the post. The feature that has more influence on the mechanical properties of the posts is the type of fiber.
authors.affiliation: Department of Surgery and Medical and Surgical Specialties, Faculty of Medicine and Dentistry, University of Santiago de Compostela, Santiago de Compostela, A Coruña, Spain.
authors.forename: Víctor
authors.initials: V
authors.lastname: Alonso de la Peña
authors.affiliation: Department of Surgery and Medical and Surgical Specialties, Faculty of Medicine and Dentistry, University of Santiago de Compostela, Santiago de Compostela, A Coruña, Spain.
authors.forename: Iria L
authors.identifier: 0000-0002-9159-6406
authors.initials: IL
authors.lastname: Darriba
authors.affiliation: Department of Surgery and Medical and Surgical Specialties, Faculty of Medicine and Dentistry, University of Santiago de Compostela, Santiago de Compostela, A Coruña, Spain.
authors.forename: Martín
authors.initials: M
authors.lastname: Caserío Valea
authors.affiliation: Instituto de Cerámica, University of Santiago de Compostela, Santiago de Compostela, A Coruña, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Guitián Rivera
keywords: Fiber post; Flexural strength; Hardness; Mechanical properties; SEM-evaluation