PhotoCast 2 — The BULL Rule in Occlusal Adjustment

The BULL Rule in Occlusal Adjustment

In occlusal adjustment, the goal is to eliminate premature contacts (Premature Contacts) without losing the height of the functional cusps. This is where the well-known BULL Rule comes into play

BULL = Buccal Upper – Lower Lingual

That is:

In the upper jaw, grinding should be done on the buccal cusps.
In the lower jaw, grinding should be done on the lingual cusps.

This rule helps ensure that, when adjusting a restoration or denture, unwanted contacts are eliminated while the height and role of the functional cusps (such as the palatal cusps in the upper jaw and the buccal cusps in the lower jaw) are preserved.

In fact, BULL is one of the classic principles of occlusal therapy that helps the dentist maintain physiologic, stable contacts between the jaws — without changing the functional geometry of the occlusion.