BULL Rule

[DrTacoElf]

Can someone explain the BULL rule I am running into some contradiction.

Buccal facing surfaces of upper lingual facing surfaces of lower seems like it should be working surfaces but I keep seeing the reverse?

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[NAVY DDS 2010]

Can someone explain the BULL rule I am running into some contradiction.

Buccal facing surfaces of upper lingual facing surfaces of lower seems like it should be working surfaces but I keep seeing the reverse?

If you are referring to BULL rule in regards to dentures, then it is referring to the buccal CUSPs of upper arch is in contact with lingual CUSPs of the lower arch in working (lateral) excursions. It is NOT referring to the buccal and lingual inclines as you mentioned.

Now, the BULL rule has also been used when remembering which cusps a not touching when teeth are in MI.

 

[OceanDMD]

Can someone explain the BULL rule I am running into some contradiction.

Buccal facing surfaces of upper lingual facing surfaces of lower seems like it should be working surfaces but I keep seeing the reverse?

Rule of BULL refers to the nonworking cusps, I guess because its harder to remember the rule of LUBL for the working. When adjusting or rebuilding a bite, the working cusps for the maxillary arch are the lingual cusps, they occlude in the fossa or interprox marginal ridges, and the working cusps for the mandibular arch are the buccal cusps. When you have a patient go into lateral excursions and you see a mark riding up the buccal incline of the lingual cusp(non-working intereference) on a mandibular molar/premolar, this should be adjusted. If there isn't insufficient canine guidance or group function, you may not be able to fix this situation (say a giant overjet or end to end Occlusion).

With respect to dentures, I believe it refers to what to adjust if the bite is off/needs balanced. IN other words you adjust the lingual incline of the buccal upper cusp, and/or the buccal incline of the lingual lower cusp. Leave the cusp tips of the working cusps alone. If the bite is significantly off, adjust the opposing fossa and marginal ridges and leave the cusp tips alone.


I think this has been brought up before in other threads and understanding how this works is HUGE. It will save you tons of bite adjustments and iatrogenic pain.