Tongue thrust (also called reverse swallow or immature swallow) is a pseudo-pathological name of what is either considered a normal adaptive lip seal mechanism, whereby normal nasal breathing or normal swallowing can occur. Or, it is seen as an oral myofunctional disorder - a tongue muscle pattern that is perceived as clinically abnormal and in which the tongue protrudes anteriorly to seal otherwise incompetent lips. Tongue thrusting is only seen during speech, swallowing or eating, and in order to close otherwise incompetent lips on background of an almost ubiquitous small lower jaw and anterior open bite. The behaviour is apparent only during a normal awake state, and whilst the tongue (and rest of the body) is in normal resting tone. By descriptive inference, tongue thrusting is impossible during deep sleep, or non-tone phases; or in particular during non-conscious states. Nearly all infants exhibit a swallowing pattern involving forward tongue tip push as part of infant suckling behaviour . By six months of age most lose the forward extent of this push once paediatric incisal teeth erupt, and normal lip seal is automatically acquired as solid foods begin. There are thus two community and clinical professional views of the observation of tongue thrusting behaviour that persists past the neonatal period. 1. Either it is a normal adaptive means of closing an open (or incompetent) lip state, caused by a unique combination of anatomical reasons, or 2. Tongue thrusting is the cause or potentiator of an open or incompetent lip state, and which resists efforts at behavioural change or clinical attempt at remedy. In generality, tongue thrusting is poorly understood. In particular it lacks consensus on many points of description, causality, effect or management and between the various clinical groups that each offer different forms of treatments or philosophies of professional interest. The classical view of tongue thrusting Since 1958, the term "tongue thrust" has been described and discussed in speech and orthodontic (dental) publications and by a range of writers - and speaking from specific non-medical professional perspectives and clinical biases - as a pathological event that exists as an entity for itself and without fundamental or primary functional or necessary cause. Both the general dental and speech pathologist classical views are that tongue thrusting causes both the dentofacial abnormality of anterior open bite, and the incompetent lip seal and swallowing and speech effects associated with tongue thrust. In both professions,