In a maxillary complete denture, what modification accounts for the coronoid process during mandibular movement?

Correct answer: B. Reduce the thickness of the distobuccal flange

• A. Increasing thickness worsens the interference and guarantees displacement on wide opening.
• B. CORRECT. As the mandible opens widely or moves laterally, the CORONOID PROCESS travels forward and medially, encroaching directly on the DISTOBUCCAL flange region of the maxillary denture. If that flange is too thick or overextended, the coronoid strikes it and dislodges the denture during wide opening, yawning or excursive movement. The remedy is to REDUCE the thickness of the flange in that area — a space often called the coronoid or zygomatic buccal space.
• C. Midpalatal relief addresses a torus or thin tissue over the raphe — a support and comfort issue, not a coronoid one.
• D. The posterior palatal seal governs retention at the posterior border and has no relationship to coronoid interference.

Note: Classic patient complaint: 'the upper denture drops when I yawn or chew on one side.' If retention is otherwise good and it fails only during wide opening or excursion, examine the DISTOBUCCAL flange for coronoid interference.