Dental General f4b6fca5 According to ADA specification of toothbrush width of brush head should be: A 5/8-3/8inches. B 5/16-3/8inches. C 5/8-3/16inches. D 5/16-3/16inches. High-Yield Explanation Length of brush head: 1-1.25 inches. Width of brush head: 5/16-3/2 inches. Bristles: 2-4 rows. Tufts in a row: 5-12 tufts