Mechanical Properties of Dental Composite Materials Reinforced With Micro and Nano-Size Al2O3 Filler Particles

Composite specimens were prepared by dispersion of various amounts of nano-sized al2o3 fillers in a monomer system containing 60% bis-gma and 40% tegdma. for comparative purposes, composite samples containing micrometer size al2o3 fillers were also prepared following the same procedure. the mechanical properties of the light- cured samples were assessed by three-point flexural strength, diametral tensile strength, and microhardness tests. the results indicated a more than hundred percent increase in the flexural strength and nearly an eighty percent increase in the diametral tensile strength values in the samples containing nano-size al2o3 filler particles. it is interesting to note that, this improvement was observed at a much lower nano-size filler content. fracture surfaces analyzed by scanning electron microscopy, indicated a brittle type of fracture in both sets of specimens.