| 摘要 |
PROBLEM TO BE SOLVED: To provide polymer materials for production of a dental positioning appliances, which are less susceptible to stress relaxation and creep and less susceptible to degradation caused by exposure to saliva and other chemical substances existing in a patient's mouth. SOLUTION: The polymer shell of a removable dental positioning appliance is formed of transparent polymeric materials having a tensile strength at the yield point greater than 6,000 pounds per square inch (psi), an elongation at yield greater than 4%, an elongation at break greater than 80%, a tensile modulus greater than 200,000 psi, a flexural modulus greater than 200,000 psi, stress relaxation over time not higher than 50%, and light transmittance between 400 nm and 800 nm greater than 75%. COPYRIGHT: (C)2011,JPO&INPIT
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