Air polishing on posterior teeth uses what angulation?

• A. 60°
• B. 90°
• C. 80°
• D. 70°

Answer: (C)

Directing the air-polishing spray at a near-perpendicular angle to the tooth surface is most effective for posterior teeth. This orientation lets the abrasive particles contact the back teeth surfaces—including the hard-to-reach buccal, lingual, and interproximal areas—without grazing the gingiva. Angles that are too shallow don’t reach the residues well, while a fully perpendicular or overly steep angle can limit access in the posterior regions and increase tissue irritation. So, a near-perpendicular, slightly oblique approach is preferred for cleaning the posterior teeth.