| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2006: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2005: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2004: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2003: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Three sort of photocatalyst titanium dioxide in different particle sizes of 6, 30, 180nm were added to the experimental composite resins by replacing the part of silica filler with 1, 3, 5, 10, 20, 30 mass%. The compressive strength, diametral tensile strength and bending strength of cured experimental composites was observed. The antibacterial effect was investigated by means of e. coli, and fracture surfaces were observed by SEM and EPMA, then the following conclusions were obatained.
1) The compressive strength showed the tendency of decreasing when the contents of titanium dioxide increased, and in more than 20% the compressive strength decreased as the particle size of titanium dioxide increased.
2) The diametral tensile strength showed the similar tendency of decreasing with the increase of titanium dioxide content, and when the particle size became more than 30nm, the diametral tensile strength decreased with the addition of more than 10%.
3) The bending strength decreased rapidly with the addition of more than 20%, and the smaller the particle sizes became, the greater the bending strength became.
4) The antibacterial effects were observed for all experimental composite containing titanium dioxide, especially the composites containing titanium oxide of particle size of more than 30nm showed significant antibacterial effect.
5) From the observation of fracture surfaces by SEM and EPMA, the mixed conditions of titanium dioxide were homogeneous.
From these observations, the light curing composite resins containing photocatalyst titanium dioxide have great potential as an antibacterial dental filling material.
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