During protrusive interference, which interference is involved?

Correct answer: D. Canine interference

• A. During protrusion, posterior teeth should SEPARATE (posterior disclusion) in ideal occlusion. If posterior teeth TOUCH during protrusion, that IS the protrusive interference — but this is described in option A correctly. The question asks which specific type of interference.
• B. An anterior open bite means the anterior teeth don't contact — this would actually PREVENT protrusive interference because there are no anterior teeth to guide protrusion.
• C. Loss of canine guidance would lead to group function or posterior contacts — but this is not the specific 'protrusive interference.'
• D. ⚠️ Protrusive interference refers to POSTERIOR tooth contacts that occur during protrusive mandibular movement. However, the source lists 'canine interference' as the answer. Canine interference typically refers to WORKING-SIDE interference. For INBDE purposes: protrusive interference = posterior (molar) teeth contacts during protrusion. Study the distinction: working side = canine/lateral interference; protrusive = posterior tooth contact during protrusion.