title: The influence of nanoscale inorganic content over optical and surface properties of model composites.
abstract: OBJECTIVE
  To investigate the influence of nanoscale inorganic content over optical and surface properties of model composites before and after ageing.
  
  
  METHODS
  Three model composites were formulated with silica fillers in nanoscale of 7 nm (G1), 12 nm (G2) and 16 nm (G3), at 45.5% by weight in a matrix of BisGMA/TEGDMA 1:1. Color coordinates (CIE L*a*b* parameters), color difference (ΔE*), translucency parameter (TP), surface gloss (SG) and surface roughness (SR) were measured before and after ageing procedures of immersion in water and toothbrush abrasion. Surface hardness (SH) were evaluated before and after immersion in absolute ethanol. Results were submitted to two-way ANOVA followed by Tukey's post hoc test performed at a pre-set alpha of 0.05.
  
  
  RESULTS
  Regarding CIE L*a*b* parameters, a darkening, a redness and a blueness effect, were respectively detected after water storage for all groups. Smaller filler sizes (G1) had the highest CIE b* values, whereas medium (G2) (p<0.05) had higher values than larger fillers (G3) (p<0.05) either before or after water immersion. Toothbrush abrasion did not produce any significant effect on CIE a* and CIE b* values, however increased CIE L*, decreased TP in addition to produce rougher and matte surfaces in all groups. Filler size did not influence ΔE* (p>0.05), although a tendency towards lower values in smaller filler materials was observed. Ageing after immersion in absolute ethanol decreased SH for all model composites.
  
  
  CONCLUSIONS
  Filler sizes and ageing procedures influenced the optical and surface properties of the nanostructured composites evaluated in this study.
  
  
  CONCLUSIONS
  Filler size influenced optical and surface properties of resin composites. Materials containing smaller filler size offered improved optical stability and surface properties that can lead to longer maintenance of the restoration's appearance in the oral environment.
authors.affiliation: School of Dentistry, Federal Fluminense University, Niterói, Brazil.
authors.forename: Vinícius Esteves
authors.initials: VE
authors.lastname: Salgado
authors.forename: Larissa Maria
authors.initials: LM
authors.lastname: Cavalcante
authors.forename: Nick
authors.initials: N
authors.lastname: Silikas
authors.forename: Luis Felipe J
authors.initials: LF
authors.lastname: Schneider
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002164:Camphor / Q000031:analogs & derivatives / Q000737:chemistry; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry; D006244:Hardness; D006801:Humans; D008027:Light; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D058567:Photoinitiators, Dental / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014099:Toothbrushing / Q000295:instrumentation; D014867:Water / Q000737:chemistry; D062366:para-Aminobenzoates / Q000737:chemistry
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D058567:Photoinitiators, Dental; D011109:Polymethacrylic Acids; D012997:Solvents; D062366:para-Aminobenzoates; D014867:Water; C020946:triethylene glycol dimethacrylate; D000431:Ethanol; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D002164:Camphor; D012822:Silicon Dioxide; C030747:ethyl 4-dimethylaminobenzoate; C553149:camphorquinone
keywords: Ageing; Filler size; Inorganic content; Nanocomposites; Optical properties