title: Hardness and modulus of elasticity of primary and permanent teeth after wear against different dental materials.
abstract: OBJECTIVE
  The purpose of this study was to determine the Young's modulus and the hardness of deciduous and permanent teeth following wear challenges using different dental materials.
  
  
  METHODS
  Wear challenges were performed against four dental materials: A resin-based fissure sealant (Fluoroshield(®)), a glass ionomer based fissure sealant (Vitremer(®)), and two microhybrid composite resins (Filtek Z250 and P90(®)). Using the pin-on-plate design, a deciduous or a permanent tooth was made into a pin (4 mm × 4 mm × 2 mm) working at a 3 N vertical load, 1 Hz frequency, and 900 cycles (15 min) with Fusayama artificial saliva as a lubricant. Before and after the tribological tests, the hardness and elasticity modulus of the tooth samples were measured by creating a nanoindentation at load forces up to 50 mN and 150 mN. All of the results were statistically analyzed using ANOVA and post-hoc Duncan's tests (P < 0.05).
  
  
  RESULTS
  No difference in hardness was encountered between deciduous and permanent teeth (P < 0.05) or modulus of elasticity (P < 0.05) before or after the wear challenges for all of the dental materials tested.
  
  
  CONCLUSIONS
  Wear challenges against the studied dental materials did not alter the properties of permanent or deciduous teeth after the application of a 3 N load.
authors.affiliation: Departament of Dentistry, Federal University of Valleys of Jequitinhonha and Mucuri, Diamantina, MG, 39100-000, Brasil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Galo
authors.affiliation: Department of Pediatric Clinics, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil.
authors.forename: Marta Maria Martins Giamatei
authors.initials: MMMG
authors.lastname: Contente
authors.affiliation: Department of Pediatric Clinics, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil.
authors.forename: Daniel
authors.initials: D
authors.lastname: Galafassi
authors.affiliation: Department of Pediatric Clinics, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Borsatto
keywords: Composite resin; glass ionomer sealant; nanoindentation; resin fissure sealant; two-body wear