Which factor governs posterior disclusion during protrusive and lateral mandibular movements?

• A. Condylar guidance
• B. Anterior guidance
• C. Posterior disclusion
• D. Occlusal plane

Answer: (B)

Anterior guidance is what controls posterior disclusion during forward and side-to-side jaw movements. The way the front teeth come together and guide the mandible as it slides forward (protrusion) or laterally determines when the posterior teeth lose contact. A well-defined, steeper anterior guidance means the mandible moves with an anterior-influenced path that separates the posterior teeth to avoid interference. If anterior guidance is inadequate or flat, the posterior teeth may remain in contact during those movements, reducing disclusion.

Condylar guidance sets the path of the condyle itself, which influences the overall movement but not the disclusion of posterior teeth during these movements. The occlusal plane helps organize where contacts occur but does not govern the disclusion mechanism in these excursions.