disclusion

Disclusion is a term used in dentistry to describe the disengagement or separation of occluding surfaces of teeth during jaw movements. It refers to the reduction or elimination of contact between posterior teeth (the molars and premolars) when the mandible moves away from centric occlusion, such as during protrusion or lateral excursions. The goal of disclusion is to minimize traumatic occlusal loads on posterior teeth by guiding the jaw in a way that reduces grinding forces on those surfaces.

During functional movements, disclusion is achieved through occlusal design and tooth arrangement that directs movement as the anterior teeth guide the mandible. In a typical healthy pattern, the canines provide anterior guidance, causing posterior teeth to disclude during lateral movements (working side). If canines are worn or absent, other teeth, such as premolars, may contribute to disclusion through a mechanism known as group function, or custom restorations may be used to restore proper disclusion.

Clinical relevance includes optimizing occlusal harmony in orthodontics, restorative dentistry, and prosthodontics. Practitioners adjust contacts to ensure appropriate disclusion, which can involve selective grinding, restorative reshaping, or occlusal splints. Insufficient or excessive disclusion can contribute to occlusal instability, wear, or temporomandibular symptoms in some patients.

Disclusion time is a related concept describing the duration during which posterior teeth remain disengaged during jaw movements; it can be assessed with specialized occlusal analysis tools to evaluate and refine occlusion.