Occlusal Splint

Definition

An occlusal splint is a removable device that covers the occlusal surfaces of an arch and creates a new occlusal relationship between the two jaws. Its most common and best-documented form is the stabilization splint — full-arch coverage in hard acrylic (night guard, Michigan splint) — in which every opposing tooth contacts the splint's flat surface simultaneously and evenly, and in excursive movements, anterior and canine guidance disclude the posterior teeth. Other types also exist: soft splints, partial-coverage splints such as anterior deprogrammers and the NTI, and anterior repositioning splints, which aim to change the position of the condyle and disc.

Concept Boundary & Misconceptions

A recurring mistake is treating the splint as a "treatment for bruxism." A splint does not eliminate bruxism behavior. EMG studies show that muscle activity may temporarily decrease, stay the same, or even increase in some patients. The splint's main function is protective: force is directed into the acrylic instead of the enamel, ceramic, and restoration.

The second misconception concerns soft splints. Their ease of fabrication and better initial tolerance have led to their use as a cheaper substitute, even though their non-adjustable surface creates uneven contacts, wears out quickly, and increases muscle activity in some patients. Their proper place is sports protection, not bruxism management.

The third misconception concerns partial-coverage splints. A device that covers only the anterior teeth leaves the posterior teeth out of contact, and if used uncontrolled for a long period, it can produce exactly what we deliberately use in the Dahl concept: posterior eruption and a permanent change in occlusion. This complication does not occur with full-arch coverage.

Role in Clinical Decision-Making

A splint has three distinct functions that should not be conflated: protecting tooth structure and restorations in a bruxer patient, deprogramming the muscles to obtain a record in centric relation, and serving as a reversible test of patient tolerance before an irreversible decision such as raising the vertical dimension. The design decision (full or partial coverage, maxillary or mandibular, hard or soft) should follow from this specific goal, not from habit.

A splint that is delivered without adjustment and follow-up becomes, itself, an agent of occlusal change. A splint does not eliminate force — it only redirects the path by which force reaches the tissues — and a treatment that misses this distinction turns a protective device into a source of harm.