Poly(methyl methacrylate) (PMMA), also known as acrylic or acrylic glass, is a transparent thermoplastic often used in sheet form as a lightweight or shatter-resistant alternative to glass. Dental pmma discs is made of a millable resin with properties that closely mirror those of a nature tooth, making it a fawless solution for laboratories to reduce processing time by eliminating labor-intensive metal investing and casting procedures in the workflow process. http://www.zirconiablocks.com/dental-pmma-discs/