Disclusion on the working side describes separation of posterior teeth on the side where the mandible moves toward the:

• A. Working side
• B. Non-working side
• C. Centric relation
• D. Neutral zone

Answer: (A)

During lateral jaw movement, disclusion means the posterior teeth separate to allow the movement to proceed without interference. The side toward which the mandible moves is the working side, and that is where posterior teeth are separated during the excursion. This separation occurs so the guiding influence of the anterior teeth (or canines) and the path of the moving condyle aren’t blocked by posterior occlusion, letting the mandible glide smoothly along its path. The other side is the nonworking (balancing) side, where the pattern of contacts can differ (often with more or less posterior contact depending on the occlusal scheme), but the definition here specifically describes separation on the side of movement. Centric relation is a fixed jaw position, not about movement-induced disclusion, and the neutral zone is the space where the cheeks and lips are at rest, not where occlusal disclusion occurs.