What is the principal purpose of anterior guidance in an occlusal scheme?

Patient case: Bruxist requiring a posterior crown and a splint

Patient: Adult with established parafunction

Chief complaint: Requires a crown; already wears a hard occlusal splint.

Background: Long-standing bruxism. Wears a hard acrylic splint nightly.

Current findings: Generalised occlusal wear. The splint is presented for review.

To disclude the posterior teeth in excursions, reducing the load on the muscles of mastication
To cure temporomandibular joint disorders
To restrict the border movements of the mandible
To alter centric relation

Show answer and explanation

Correct answer: A. To disclude the posterior teeth in excursions, reducing the load on the muscles of mastication

A. Anterior guidance causes the posterior teeth to separate immediately in excursive movements. Because elevator muscle activity is reflexly reduced when posterior contacts are absent, the loads transmitted to teeth, joints and musculature all fall. This is the rationale behind both the anterior guidance concept and the anterior ramp on a splint.
B. It can relieve symptoms, but 'curing' a temporomandibular disorder overstates the case considerably.
C. Border movements are determined by joint and ligament anatomy, not by tooth guidance.
D. Centric relation is a bone-to-bone joint relationship and is not altered by anterior guidance.