... Carbide Burrs: 1.6mm shank. for finishing gold, other metals and acrylic plastic materials. Dental Carbide Burrs:1.6mm shank.for ... finishing gold, other metals and acrylic plastic materials. 1. Thick tooth (ISO Numbers, 220), the ... Numbers, in 190), blue circle, mainly used for scraps area alloy and acrylic - resin3. Fine tooth (ISO Numbers, 140), red circle, the ...