During protrusive movement, which teeth primarily experience disclusion?

• A. Disclusion of posterior teeth
• B. Disclusion on non-working side
• C. Centric relation
• D. Neutral zone

Answer: (A)

During protrusive movement, the mandible slides forward and the anterior teeth act as the guide. This anterior guidance causes the posterior teeth to separate and lose contact with the opposing teeth, a disclusion of the posterior dentition. The purpose of this disclusion is to protect the posterior teeth from grinding forces during forward movement and to allow a smooth forward glide driven by the anterior teeth. In contrast, the other terms don’t describe this forward-slide disclusion: centric relation is a jaw position, not a movement that causes disclusion; the neutral zone is the space between teeth and the lips while at rest; and non-working side disclusion refers to the lateral movement where the posterior teeth on the non-working side disclude, not during protrusion.