A junction of three surfaces called?

• A. Point Angle
• B. Line Angle
• C. Junction of Surfaces
• D. Vertex

Answer: (A)

In cavity preparation, how walls meet determines the name of the angle. When just two walls meet, you have a line angle. When three walls meet at a corner inside the preparation, that junction is called a point angle. So the corner where three walls—such as buccal, lingual, and occlusal (or mesial/distal) walls—come together is a point angle. The term vertex isn’t used here to describe this internal junction in standard restorative terminology, and a generic “junction of surfaces” isn’t the specific dental term needed.