title: The volumetric fraction of inorganic particles and the flexural strength of composites for posterior teeth.
abstract: OBJECTIVE
  To evaluate the content of inorganic particles and the flexural strength of new condensable composites for posterior teeth in comparison to hybrid conventional composites.
  
  
  METHODS
  The determination of the content of inorganic particles was performed by mass weighing of a polymerized composite before and after the elimination of the organic phase. The volumetric particle content was determined by a practical method based on Archimedes' principle, which calculates the volume of the composite and their particles by differential mass measured in the air and in water. The flexural strength of three points was evaluated according to the norm ISO 4049:1988.
  
  
  RESULTS
  The results showed the following filler content: Alert, 67.26%; Z-100, 65.27%; Filtek P 60, 62.34%; Ariston pHc, 64.07%; Tetric Ceram, 57.22%; Definite, 54.42%; Solitaire, 47.76%. In the flexural strength test, the materials presented the following decreasing order of resistance: Filtek P 60 (170.02 MPa)>Z-100 (151.34 MPa)>Tetric Ceram (126.14 MPa)=Alert (124.89 MPa)>Ariston pHc (102.00 MPa)=Definite (93.63 MPa)>Solitaire (56.71 MPa).
  
  
  CONCLUSIONS
  New condensable composites for posterior teeth present a concentration of inorganic particles similar to those of hybrid composites but do not necessarily present higher flexural strength.
authors.affiliation: Department of Dental Materials and Prosthodontics, School of Dentistry of Araraquara, Universidade Estadual Paulista, R Humaitá 1680, CEP 14801-903, Araraquara, SP, Brazil. adabo@foar.unesp.br
authors.forename: Gelson Luis
authors.initials: GL
authors.lastname: Adabo
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: dos Santos Cruz
authors.forename: Renata Garcia
authors.initials: RG
authors.lastname: Fonseca
authors.forename: Luís Geraldo
authors.initials: LG
authors.lastname: Vaz
mesh_terms: D000388:Air; D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D006801:Humans; D007287:Inorganic Chemicals / Q000737:chemistry; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D018583:Pliability; D012822:Silicon Dioxide; D012833:Siloxanes / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013729:Terpenes / Q000737:chemistry; D014867:Water; D015040:Zirconium
chemical_list: C406265:Alert composite resin; C409382:Ariston pHc; D003188:Composite Resins; C421785:Definite composite resin; D003764:Dental Materials; C438835:Filtek P60 Composite Resin; D007287:Inorganic Chemicals; D008689:Methacrylates; D012833:Siloxanes; C113049:Solitaire composite resin; D013729:Terpenes; C121818:Tetric ceram; C083568:Z100 composite resin; D014867:Water; D012822:Silicon Dioxide; D015040:Zirconium