What is the term for the vertical movement of a tooth away from the occlusal plane?

What is the term for the vertical movement of a tooth away from the occlusal plane?

• A. Extrusion
• B. Intrusion
• C. Protrusion
• D. Retransmission

Answer: (B)

Intrusion is the vertical movement of a tooth toward the apex, away from the occlusal plane. This movement lowers the tooth into the bone and reduces the vertical dimension, which is useful for correcting deep bites or bringing supra-erupted teeth back into alignment. It’s the opposite of extrusion, which moves a tooth upward toward or beyond the occlusal plane, increasing the vertical height. Protrusion is a forward (horizontal) movement of teeth, not a vertical change relative to the occlusal plane. The other term listed isn’t a standard orthodontic term.

Intrusion is the vertical movement of a tooth toward the apex, away from the occlusal plane. This movement lowers the tooth into the bone and reduces the vertical dimension, which is useful for correcting deep bites or bringing supra-erupted teeth back into alignment. It’s the opposite of extrusion, which moves a tooth upward toward or beyond the occlusal plane, increasing the vertical height. Protrusion is a forward (horizontal) movement of teeth, not a vertical change relative to the occlusal plane. The other term listed isn’t a standard orthodontic term.