1999 Fiscal Year Final Research Report Summary
Development of New Tissue Conditioners and Rheological Properties for Dental Clinical Characteristics
| Project/Area Number |
10671814
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
補綴理工系歯学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
KATAKURA Naoyuki School of Dentistry, Tohoku University, Associate Professor, 歯学部, 助教授 (70005031)
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| Co-Investigator(Kenkyū-buntansha) |
HOSOTANI Makoto School of Dentistry, Tohoku University, Research Associate, 歯学部, 助手 (70199503)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Tissue conditioner / Poly(butyl methacrylate) / Plasticizer / Rheology / Dynamic viscoelasticity / Flow property / Particle size / Activation energy |
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| Research Abstract |
The dental clinical characteristics of new experimental tissue conditioners which consist of poly(butyl methacrylate) PBMA powder and a liquid plasticizer were investigated from the standpoint of rheological properties.
1. Syntheses of polymers
Homopolymer and copolymers of n-butyl methacrylate(n-BMA) and iso-butyl methacrylate (iso-BMA) were synthesized by suspension polymerization in aqueous gelatin. The particle sizes of polymers were from 32 to 55 μm.
2. Flow properties of plasticizers
The viscosity(η)-temperature(T) relationships of fur plasticizers were measured and flow activation energies were calculated from the plot of ln η vs. 1/T. In this studies, the benzyl benzoate(BB) was selected by considering the activation energy and the biological safety.
3. Flow properties of powder and liquid mixtures
The apparent viscosity-time relationships of mixtures of synthesized polymer powders and plasticizer BB containing 5 mass% ethanol were measured by the cone-plate viscometer. After three or four minutes, the viscosities of mixtures increased rapidly with gelation. It was found that poly(iso-butyl methacrylate) iso-PBMA and copolymer (COP64) of 60 mol% n-BMA and 40 mol% iso-BMA were useful and practical for tissue conditioners.
4. Dynamic viscoelasticity of powder and liquid mixtures
The viscoelastic properties of tissue conditioners after gelation were investigated under dynamic conditions. The dynamic viscoelastic data of storage modulus G' and loss tangent tan δ versus frequencies at different temperatures were superimposed to a master curve by application of the time-temperature superposition principle. By comparing new experimental materials with a commercially available tissue conditioner, it was suggested that PBMA had the desirable properties for tissue conditioners.
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