title: Creep and dynamic viscoelastic behavior of endodontic fiber-reinforced composite posts.
abstract: OBJECTIVE
  Fiber-reinforced composite (FRC) posts have gained much interest recently and understanding of their viscoelastic properties is important as they can be used in stress-bearing posterior restorations. The aim of this study was to evaluate the creep behavior and the viscoelastic properties of four commercial FRC posts under different temperatures and different storage conditions.
  
  
  METHODS
  The FRC posts tested were Glassix, C-Post, Carbonite and Snowlight. For the creep measurements a constant load below the proportional limit of the posts was applied and the angular deformation of the specimens was recorded. The viscoelastic parameters were determined by using dynamic torsional loading under four different conditions.
  
  
  RESULTS
  All materials were susceptible to creep and exhibited linear viscoelastic behavior. Residual strain was observed in all FRC posts. The viscoelastic properties were affected by the increase of temperature and water storage (p<0.001) resulting in their decline. Carbon fiber posts exhibited better performance than glass fiber posts.
  
  
  CONCLUSIONS
  FRC posts exhibit permanent strains under regular masticatory stresses that can be generated in the oral cavity. Their properties are susceptible to changes in temperature, while direct contact with water also affects them deleteriously.
authors.affiliation: Department of Biomaterials, School of Dentistry, University of Athens, Greece. deminho@gmail.com
authors.forename: D
authors.initials: D
authors.lastname: Papadogiannis
authors.forename: R S
authors.initials: RS
authors.lastname: Lakes
authors.forename: G
authors.initials: G
authors.lastname: Palaghias
authors.forename: Y
authors.initials: Y
authors.lastname: Papadogiannis
mesh_terms: D003188:Composite Resins; D004548:Elasticity; D011176:Post and Core Technique; D013314:Stress, Mechanical; D013696:Temperature; D014783:Viscosity; D014867:Water
chemical_list: D003188:Composite Resins; D014867:Water