title: Effect of filler size and shape on local nanoindentation modulus of resin-composites.
abstract: The aim of this study was to determine the Young's moduli (E) of a series of model dental resin-composites using nanoindentation, and to examine how E was influenced by differences in filler-size and shape. Materials with different filler-sizes and shapes but constant filler volume-fraction were investigated. Disc specimens, mounted in polystyrene resin were mechanically polished and tested with a nanoindenter. One-way ANOVA and Bonferroni test were used for the statistical analysis. Regression analysis was used to investigate the correlation between E and filler-size. E ranged from 9.31 to 12.54 GPa for spherical fillers and from 14.09 to 17.03 GPa for irregular fillers. Statistically significant differences were found among the groups. Strong quadratic correlations were observed between E and filler-size for unimodal materials with spherical and irregular fillers, but were not statistically significant. Filler-size and shape seemed to be fine-tuning factors for E.
authors.affiliation: Biomaterials Science Research Group, School of Dentistry, The University of Manchester, Higher Cambridge Street, Manchester, M15 6FH, UK.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Masouras
authors.forename: Riaz
authors.initials: R
authors.lastname: Akhtar
authors.forename: David C
authors.initials: DC
authors.lastname: Watts
authors.forename: Nick
authors.initials: N
authors.lastname: Silikas
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D006244:Hardness; D006245:Hardness Tests; D008420:Manufactured Materials; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010316:Particle Size
chemical_list: D003188:Composite Resins; D003764:Dental Materials