title: Effect of porous glass-ceramic fillers on mechanical properties of light-cured dental resin composites.
abstract: OBJECTIVE
  The aim of this work was to study the effect of porous particles on the mechanical properties of dental resin composites.
  
  
  METHODS
  Two kinds of glass-ceramic powders with different calcium-mica to fluorapatite ratio were used as inorganic fillers for light-cured dental resin composites. The glass-ceramic particles were etched to introduce porous structures. The microstructures of particles and the fractography of dental composites were observed using SEM/EDS. The crystalline phases in the fillers were determined by XRD. The specific surface areas (SBET) of porous fillers were tested to show the degree of porosity. 6 samples were prepared for each bending strength test, which was conducted in a Mechanical Testing System.
  
  
  RESULTS
  The results show that the bending strength does not vary monotonically with the porosity of the particles. For the glass-ceramics with a high nominal calcium-mica to fluorapatite ratio, the dental resin filled with porous particles has a higher strength than that filled with dense particles; however, for the glass-ceramics with a low nominal calcium-mica to fluorapatite ratio, the dental resin filled with porous particles has a lower strength.
  
  
  CONCLUSIONS
  The study indicates that the porosity itself is not a decisive factor for strengthening of dental resin composites. The composition of the glass-ceramic particles and the porous structure are also essential factors influencing the mechanical strength. The investigation on the effect of porous glass-ceramic fillers will provide more understanding on the mechanical properties of dental resin composites and will help with the design of new dental restorative materials.
authors.affiliation: State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, Hunan, PR China. yonliu11@yahoo.com.cn
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
authors.forename: Yanni
authors.initials: Y
authors.lastname: Tan
authors.forename: Ting
authors.initials: T
authors.lastname: Lei
authors.forename: Qijun
authors.initials: Q
authors.lastname: Xiang
authors.forename: Yunjuan
authors.initials: Y
authors.lastname: Han
authors.forename: Baiyun
authors.initials: B
authors.lastname: Huang
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D001031:Apatites / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003799:Dental Stress Analysis; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D019563:Mechanics; D010316:Particle Size; D018583:Pliability; D016062:Porosity
chemical_list: D000538:Aluminum Silicates; D001031:Apatites; D003188:Composite Resins; C023506:Glass ceramics; C025105:fluorapatite; C011934:mica