The action of bringing the mandibular and maxillary teeth into contact. A close bite describes a malocclusion where there is an abnormally deep overlap of the incisors when the posterior teeth are in occlusion. An open bite is a form of malocclusion in which there is a failure of some teeth to meet in any mandibular position when the teeth of the jaws are brought into occlusion. An open bite may be hereditary, due to external influences such as habits, or induced as part of orthodontic therapy. An anterior open bite (AOB) exists when there is no vertical overlap of the lower incisors by the upper incisors and when the anterior teeth fail to occlude in any position of the mandible. It may be in the midline, often produced by dummy sucking over a prolonged period of time, or to the side of the midline, typically seen due to prolonged digit sucking. An anterior open bite is often associated with a tongue thrust. A closed bite is a decrease in the occlusal vertical dimension, usually resulting from excessive tooth wear or loss of posterior tooth support. An edge-to-edge bite exists where the mandibular and maxillary incisors occlude along their incisal edges and do not overlap. A locked bite occurs when lateral mandibular movements are restricted or prevented by the cuspal interference of the teeth. A posterior open bite exists when the posterior teeth on one side (unilateral) or both sides (bilateral) fail to come into vertical contact. It occurs more rarely than anterior open bite and the aetiology is less well understood. It can occur due to submergence of the primary molars or failure or arrest of eruption of the permanent buccal segment teeth; more rarely posterior open bite is seen in association with unilateral condylar hyperplasia. A scissors bite (crossbite, X-bite) occurs if one or more teeth in the upper buccal segment is positioned so that its palatal cusp occludes buccal to the buccal cusp of a lower tooth: it can involve a single tooth or a complete quadrant, and can involve one side (unilateral) or both sides (bilateral) of the arch and be either anterior or posterior.
Anterior open bite