| Popis: |
The relationship between filler type, filler content, and matrix resin composition and viscosity, and the flow characteristics of composite formulations were investigated. The structures of three newly synthesized monomers, i.e., 3F Bis-GMA, 6F Bis-GMA (Bis-GMA analogues) and IP AGDM (based on phthalic acid) were analyzed to determine their viscosity and polymerization shrinkage. Viscosities were determined with a cone and plate viscometer and shrinkages were determined gravimetrically. All three experimental monomers required less dilution than Bis-GMA, and they exhibited remarkable reductions in polymerization shrinkage relative to Bis-GMA. Bis-GMA and 4 experimental Bis-GMA analogues were also evaluated. For each monomer-filler combination, increasing filler contents resulted in monotonic plasticities. The maximum filler contents appeared to be an attribute of the particular filler rather than a matrix resin characteristic. Plasticity differences existed, unexpectedly, even at constant filler contents and matrix viscosities. Evidence was found that the plasticity varied with the base monomer composition and the amount of TEGDMA present. |
