occlusion

Occlusion is the blockage or closing of an opening, or the obstruction of sight by an intervening object. The term is used across disciplines to describe the state in which one object interrupts another's path or flow, or where surfaces contact. The precise meaning depends on the field, but occlusion generally involves some form of exclusion, concealment, or contact between entities.

In medicine and biology, occlusion most often refers to blockage within a vessel or duct. Vascular occlusion can be caused by thrombosis, embolism, spasm, or atherosclerotic plaques and may lead to ischemia or tissue death. Retinal artery occlusion is an ophthalmic emergency that can cause sudden vision loss. Occlusion can also occur in other organs, such as the heart or brain, where disruption of blood supply can have serious consequences.

In dentistry, occlusion describes how the upper and lower teeth meet when the jaw closes. Static occlusion refers to teeth contact in a closed mouth, while dynamic occlusion concerns contacts during jaw movements. Proper occlusion is important for chewing, jaw function, and long-term dental health; malocclusion can be treated with orthodontics, restorative work, or jaw therapy.

In computer graphics and vision, occlusion describes visibility relationships between objects. Occlusion culling and occlusion queries determine which objects are hidden from a given viewpoint, enabling efficient rendering. In stereo vision and image-based processing, occluded regions pose challenges for depth estimation and scene understanding.