Blockage of a canal, opening, passage, or vessel in the body. Occlusion can be brought on by disease (for example a pulmonary embolism) or can be medically induced. This term also describes eye-patching for the treatment of amblyopia (a defect of visual acuity) in young children.
In dentistry occlusion is the relationship between the upper and lower teeth when the jaw is shut. In a perfect occlusion the upper incisors and canines (front teeth) slightly overlap the lower ones; the front two incisors are positioned centrally within the front two lower incisors; the left upper teeth are positioned in an alternating pattern relative to the lower teeth; and the outer ridges of the lower molars and premolars (back teeth) fit in to the hollows in the corresponding upper teeth. Hardly anyone has an ideal occlusion but in most the arrangement of the teeth allows for efficient chewing and biting.