How does incisal guidance influence restorative planning for posterior teeth?

• A. It has no effect on posterior planning
• B. It requires increasing posterior cusp heights
• C. It only affects anterior teeth shade
• D. It informs the posterior disclusion pattern and helps set cusp heights and contact areas to protect posterior teeth

Answer: (D)

Incisal guidance is how the front teeth guide the jaw during movements, especially protrusion and lateral excursions. This anterior guidance sets how the back teeth should behave when the jaw moves, ensuring they disclude (stop contacting) during excursions rather than grinding against each other.

In planning posterior restorations, you design cusp heights, marginal ridges, and contact areas to create the same disclusion pattern produced by the anterior guidance. The goal is to allow posterior teeth to disengage during forward and side-to-side movements, protecting them from non-axial loads, excessive wear, or fracture. If incisal guidance is steep, you’ll expect a more pronounced disclusion of the posterior teeth during movements, so cusp height and occlusal contacts are adjusted to support that pattern. If it’s flatter, the posterior disclusion may be less pronounced, but the restoration should still permit smooth disclusion and stable centric contacts.

So, incisal guidance informs how the posterior teeth should present contacts and how tall or pronounced the cusps should be, all to keep posterior teeth protected during functional movements.