Shoulder preparation not needed. A mild chamfer or a feather-edge margin is good. 1mm buccal, lingual, and occlusal reduction is ideal, but can go to .5mm in some areas when reduction is limited. Minimum occlusal reduction of 0.5 mm; 1 mm is ideal. Adjustments and polishing: Adjust full-contour zirconia crowns and bridges using water and air spray to keep the restoration cool and to avoid microfractures with a fine grit diamond. If using air only, use the lightest touch possible when making adjustments. A football-shaped bur is the most effective for occlusal and lingual surfaces (on anterior teeth); a tapered bur is the ideal choice for buccal and lingual surfaces. Polish full-contour zirconia restorations with the porcelain polishing system of your choice.