IADR Abstract Archives
Effect of Open-mouth Position on Swallowing Function of Healthy Adults
Objectives: To clarify the effect of the open-mouth position on the swallowing function of healthy adults with videofluoroscopic examination of swallowing (VF) using gelatin food materials.
Methods: Eighteen healthy adult volunteers (6 male, 12 female; age range, 19–27 years) were studied. The volunteers freely swallowed a spoonful of jelly or pudding. This swallowing was defined as the “occlusal position.” Then they swallowed the same test material while keeping the mouth open by 10 mm. This was defined as the “open-mouth position.” We measured four events using VF images: swallowing time (from beginning of tongue tip movement to end of epiglottis movement), number of swallows (count of swallowing reflection for deglutition of a spoonful of test material), hyoid bone movement start time (from beginning of tongue tip movement to start of hyoid bone movement), and tongue–palatal contact position (point at which tongue contacted palatal plate while test material entered pharynx; contact points were defined as incisor, canine, premolar, and molar regions).
Results: The following results were obtained in the occlusal and open-mouth positions: mean swallowing time, 6.1 and 14.1 seconds; number of swallows, 2.0 and 2.6; hyoid bone movement start time, 2.1 and 6.0 seconds; and tongue–palatal contact position, incisor and molar, respectively.
Conclusions: Anchorage of the suprahyoid muscles is required to open the mouth; however, movement of these muscles is required for swallowing. Swallowing with an open mouth is a contradictory motion. The hyoid bone movement start time was delayed in the open-mouth position (anchorage of suprahyoid muscles), and gradual oral transit of the test material increased the number of swallows. These factors extended the swallowing time. The change in the tongue–palatal contact position was considered to be caused by restriction of tongue movement.
Methods: Eighteen healthy adult volunteers (6 male, 12 female; age range, 19–27 years) were studied. The volunteers freely swallowed a spoonful of jelly or pudding. This swallowing was defined as the “occlusal position.” Then they swallowed the same test material while keeping the mouth open by 10 mm. This was defined as the “open-mouth position.” We measured four events using VF images: swallowing time (from beginning of tongue tip movement to end of epiglottis movement), number of swallows (count of swallowing reflection for deglutition of a spoonful of test material), hyoid bone movement start time (from beginning of tongue tip movement to start of hyoid bone movement), and tongue–palatal contact position (point at which tongue contacted palatal plate while test material entered pharynx; contact points were defined as incisor, canine, premolar, and molar regions).
Results: The following results were obtained in the occlusal and open-mouth positions: mean swallowing time, 6.1 and 14.1 seconds; number of swallows, 2.0 and 2.6; hyoid bone movement start time, 2.1 and 6.0 seconds; and tongue–palatal contact position, incisor and molar, respectively.
Conclusions: Anchorage of the suprahyoid muscles is required to open the mouth; however, movement of these muscles is required for swallowing. Swallowing with an open mouth is a contradictory motion. The hyoid bone movement start time was delayed in the open-mouth position (anchorage of suprahyoid muscles), and gradual oral transit of the test material increased the number of swallows. These factors extended the swallowing time. The change in the tongue–palatal contact position was considered to be caused by restriction of tongue movement.