To bevel the gingival margin of a tooth during cavity preparation.Margin Trimmer N. 29 (Black’s Formula: 15-80-7-14), Mesiale Cavity preparation margin trimmers are used with a lateral scraping motion.The blade of the instrument must be always kept parallel to the cavity wall to remove unsupported enamel rods or roughness. RUBBER DAM CLAMP N. 5 RUBBER DAM CLAMP N. 5