| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 1989: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1988: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Research Abstract |
The fluidity of uncured material related to the fitness of denture base, the water absorption related to the durability and the viscoelastic properties related to the stress relaxation effect with relining for six commercial soft lining materials for denture bases were investigated. In addition, the insertion feeling, the masticatory ability, the softening effect of pain and the durability were examined in vivo using dentures relined with three typical relining materials and compared with the results in vitro as described above. The low temperature gelation type CS and the heat-curing type CSS as the acrylic resin system, the self-curing type NS and the heat-curing type MB as the silicone resin system, KD as the fluoro resin system and MS as polyolefine system were tested. CSS, KD and M (polyolefine system) were used for clinical study.
The fluidity varied with the properties of the materials. CS, CSS, NS and KD had suitable fluidity for relining, respectively. MB and MS were more elast
… More
ic than the other materials and had less flow. It seemed that they should be pressed for a sufficiently long time during a trial closure to gain the good fitness. In clinical examination, however, 90% of patients recognized the improvement of insertion feeling so that the low fluidity of M was not a troubler if gave careful consideration.
Water absorption reflected clearly the properties of the materials. After 21 weeks, amount of water absorption was 112mu g/mm^3 for CS, 83mu g/mm^3 for NS, 65mu g/mm^3 for CSS and 49mu g/mm^3 for KD. However, MB and MS absorbed almost no water after 21 weeks. These results influenced the clinical evaluation of these materials. The durability in vivo was about 13 month for CSS and M, and expected the longer period for KD. The reasons of the low durability of M with high water resistance were because its adhesion to denture base resin was poor and it was stained by the oiliness food.
The viscoelastic properties varied so greatly with materials that they could not be measured under the same measuring condition. Four materials(CSS,NS,MB and MS) had less viscosity and relatively higher elasticity, although the soft lining materials should had an adequate viscoelasticity as same as that of the raucous membrane of residual ridge. In clinical study, however, It was difficult to make clear the difference of softening effect of pain for 3 materials from the results of interview to patients. Less
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