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Sustained-release matrices for dental application

  • US 5,998,431 A
  • Filed: 04/16/1998
  • Issued: 12/07/1999
  • Est. Priority Date: 08/23/1991
  • Status: Expired due to Term
First Claim
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1. A color-changing matrix comprising two joined layers being co-extruded or co-injection molded and comprising an outer layer comprising a water-soluble polymer and a first colorant, and an inner layer comprising a water-insoluble polymer and a second colorant different from said first colorant.

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