During left lateral excursion, a patient's upper complete denture moves. Premature contact is noted on denture tooth #15 (upper left second molar). Where should the occlusal adjustment be made?

Correct answer: A. Lingual incline of the buccal cusp of the left maxillary molar

• A. Correct. When the mandible moves to the LEFT (working side), the buccal cusp of the lower left molar contacts the LINGUAL INCLINE of the BUCCAL cusp of the upper left molar. This working-side contact is where the premature contact exists. The adjustment is made on the lingual incline of the buccal cusp of the maxillary left molar (tooth #15).
• B. Right mandibular adjustments would address the non-working (balancing) side, not the working-side premature contact.
• C. The buccal incline of the buccal cusp would face outward (buccally) — not the contact area during left lateral excursion.
• D. Anterior incisal edges are adjusted for protrusive guidance, not lateral excursion posterior contacts.