3M Crowns Brand Dental Crowns Supplies, Recorder Code L77 Prefabricated crowns made of tin-silver alloy for short-term adult posterior use. Iso-Form Second Molar Replacement Crown is a soft tin-silver alloy retains shape of preparation and is easily stretched and burnished to fit prep margins. Faster placement than acrylics and chemical resin for single units for a quicker procedure. Crown set is packaged in a unique, stackable tray that provides convenient, easy storage of prefabricated crowns. • Refills of individual permanent crowns are available in boxes of five. • Made of Tin-Silver Alloy material • Crown Shape for molar and bicuspid • Size L-77