The series of coordinated muscle contractions that move a bolus of food from the oral cavity, through the esophagus, to the stomach is called swallowing.
It is a voluntary, involuntary and reflex muscular activity.
Swallowing activation depends on several factors:
degree of fineness/consistency of the food
intensity of the extracted flavour
degree of lubrication of the bolus
During swallowing the lips are closed, thus sealing the oral cavity. The teeth are brought into their maximum intercuspal position, thus stabilizing the jaw.
Stabilization of the jaw is an important part of swallowing. The mandible must be fixed so that the contraction of the suprahyoid and infrahyoid muscles can control the correct movement of the hyoid bone necessary for swallowing.
When teeth are not present, as in the newborn, the mandibular position must be strengthened by other means, i.e. by pushing the tongue forward and between the dental arches or gum pads. This type of swallowing occurs until the back teeth erupt. When the posterior teeth erupt into occlusion, the occluding teeth reinforce the stabilization of the mandible and the adult is assumed to swallow as previously described.
Sometimes the normal transition from infant swallowing to adult swallowing does not occur and what is called dysfunctional or atypical swallowing occurs. This may be due to the lack of support of the teeth due to the poor position of the teeth or the relationship of the arches. Infant swallowing can be maintained even when discomfort occurs during contact with the teeth due to tooth decay or tooth sensitivity.
The persistence of infantile swallowing beyond the physiological time can cause a labial displacement of the front teeth by the tongue, a very powerful organ composed of numerous muscles. This can present clinically, for example, as an anterior open bite (no contact with the front teeth). However, the presence of a tongue thrust condition does not necessarily lead to an altered tooth position.
In adult physiological swallowing, the jaw is stabilized by dental contacts. The average tooth contact during swallowing lasts approximately 683 ms. This is more than three times longer than when chewing. The force applied to the teeth during swallowing is approximately 30kg, or 3.5kg more than the force applied during chewing.
When the mandible is stabilized, it is brought into a posterior or retruded position. If the teeth do not fit well in this position, anterior sliding towards the intercuspal position occurs. The literature tells us that when the teeth contact evenly and simultaneously in the retruded closed position, the muscles of mastication appear to function at lower activity levels and more harmoniously during chewing.
The Dentist, Osteopath and Speech Therapist synergy can be a valid help in correcting the biomechanical and dynamic imbalances of this act.
Valentina Carlile - Osteopath expert in Osteopathy applied to voice and speech disorders since 2002. For information and reservations visit the page Contacts