Open Bite: Spaces are seen between the biting surfaces of some of the upper and lower teeth, either in front or back, when the other teeth are biting together. This places too much chewing force on the teeth that are touching (chewing forces should act on all teeth as a unit). A widened periodontal ligament occurs, which is more prone to periodontal breakdown. A patient may not be able to effectively bite food and may tend to swallow larger than normal mouthfuls that are difficult to digest. The teeth and gums are not exercised properly and become unhealthy. (Note swollen and reddened gums around lower front teeth.)
Although not always the case, a tongue-thrust swallower will usually appear to run the 100-yard dash with his lips during swallowing, as he contacts labial musculature to bring food back into the mouth before sealing it within his mouth and on top of his tongue by flowing his tongue forward and out laterally between his teeth. When he swallows, he will grimace, and then often gulp to swallow, as the tongue remains flat, giving no impetus to the food bolus entry into the pharynx.
During normal swallowing, the labial musculature will remain passive. The individual will have a poker face with no movement. The only movement observable will be in the throat area under the mandible.
The orthodontist may observe this patient’s facial contortions or passivity to quietly determine whether a tongue thrust may be present and may, of course, quickly part the patient’s lips with his fingers during the swallowing act to actually see if the patient is leaving his teeth apart and thrusting, or closing his teeth and swallowing normally. The orthodontist may enlist the aid of the parents to observe their children during swallowing at meals. If the patient’s lips contact and/or if the patient gulps to swallow, the child may be reminded by the parent to hold the teeth together during swallowing. It is important for the patient to force himself to swallow correctly to build the new correct swallowing habit.