Which cusps are considered the 'damaging cusps' because they can cause the most harm during lateral excursions by creating non-working side interferences?

Correct answer: A. Lingual cusps of upper posterior teeth and buccal cusps of lower posterior teeth (inner inclines)

• A. CORRECT. The lingual (palatal) cusps of UPPER posterior teeth and the buccal cusps of LOWER posterior teeth are the 'centric holding cusps' — they maintain vertical dimension and food-crushing function. However, it is their INNER INCLINES that can contact during non-working excursion, producing damaging interferences. The BULL rule identifies these as the contacts to avoid on the non-working side.
• B. Mesial/distal cusp positions do not define the damaging vs. functional cusp classification — it is the buccal vs. lingual position relative to the jaw arch.
• C. Lingual cusps of lower posterior teeth are non-functional on most sides and create less harmful contacts.
• D. Buccal cusps of upper posterior teeth are the 'stamp cusps' on the working side — they participate in working side contacts and are the basis of the BULL rule's upper buccal preference.