For supragingival hand instrument calculus removal, what angulation should be used between the face of the instrument and the tooth surface?

• A. 60-80°
• B. 20-30°
• C. 90°
• D. 45°

Answer: (A)

For supragingival calculus removal, you want the cutting edge to engage the deposit with a controlled bite while protecting the tooth and surrounding tissues. The face of the instrument should be about 60 to 80 degrees to the tooth surface. This range allows the edge to grip and shear calculus effectively without digging into enamel or irritating the gingiva. If the angle is too shallow, the edge slides over the calculus and becomes ineffective; if it’s too steep, the edge can gouge the tooth or traumatize the soft tissue. The 60–80 degree range provides a balance that works across different tooth surfaces and operator techniques.