Dental When instrument with primary cutting edge is perpendicular to blade then: A 1st digit of 4 digit formula omitted. B 2nd digit of 4 digit formula omitted. C 3rd digit of 4 digit formula omitted. D 4th digit of 4 digit formula omitted. 💡 Explanation When instrument with primary cutting edge is perpendicular to blade then: ✓ Correct Answer: B. 2nd digit of 4 digit formula omitted.