intercuspal

Intercuspal position (ICP), also called maximum intercuspation, is the mandibular position in which the upper and lower dentitions achieve their greatest contact. In ICP, the teeth are in maximum intercuspation, with the posterior teeth interlocking to the extent that each cusp and groove engages with its opposing fossa and ridges. It is a static tooth-to-tooth relationship determined by dentition and occlusal morphology and can be reached with the mandible in various condylar positions.

ICP is not defined by the position of the condyles. Centric relation (CR) describes the position of the mandible with the condyles seated in the glenoid fossae with the discs properly positioned, independent of tooth contact. In many individuals ICP and CR are coincident, but they may be separate when tooth wear, restorative changes, or neuromuscular factors alter tooth contacts relative to condylar position.

Clinically, ICP serves as a reference for fabricating and adjusting restorations, mounting diagnostic casts on articulators, and planning occlusal schemes. Bite registrations or occlusal wax-ups may be used to locate ICP. In some cases, occlusal adjustments or deprogramming procedures are employed to evaluate functional occlusion and separate habitual closed-position contacts from true ICP.

Because ICP is tooth-driven, it may change with dental prostheses, tooth wear, or orthodontic treatment. It is distinguished from dynamic mandibular movements such as lateral and protrusive excursions, which involve anterior guidance and cuspal disclusion.