IADR Abstract Archives
Spatial Relationships of Oropharyngeal Structures During Chewing and Swallowing
Objectives: Oropharyngeal structures are highly active during mastication and swallowing, but their spatial relationships are less understood. This study was to analyze the dynamics of soft palate(SP), tongue base(TB), and epiglottis(EG) during chewing and swallowing.
Methods: Voluntary chewing and swallowing of barium-mixed diet were video-taped(30 frames/s) for 5-10 minutes using x-ray fluoroscopy in five 7-8-month-old Yucatan minipigs. Frames of 2-5 masticatory cycles and bolus swallowing episodes from each animal were digitized using the video-analysis tool. The digitized points were the tip of SP and EG, and the midpoint of dorsal surface of TB. The reference point was the most gingival point on the distal surface of the upper last molar. An X-Y coordinate was set up in each frame to standardize the excursion ranges and direction of each structure and bolus. Previously implanted 2mm ultrasonic crystals in TB were used for calibration. All distance changes were converted to % of the given distances at rest.
Results: Distances between TB to SP, TB to EG, and EG to SP shortened at 49.21-75.01±9.69%, 4.06-25.30%±8.77%, and 5.82-26.25%±8.02 in opening, and elongated at 33.10-117.79%±35.81%, 5.41-30.18±10.68%, and 5.64-33.51±10.52% respectively in closing and power stroke during chewing. The distance between TB to SP increased immediately before swallowing, followed by a 20.14% to 60.5% decrease during swallowing. Decreased distance of 5.65% to 38.02% and 1.57% to 42.73% were observed between EG to TB and EG to SP respectively, but phasic changes of EG to TP and EG to SP were not as definitive as the change seen between SP and TB.
Conclusions: The spatial relationships of three oropharyngeal structures decrease and increase in distance and the largest changes in chewing is between TB and SP due to jaw movements. The closer spatial relationship of these three structures during swallowing propels the bolus through the oropharynx.
Methods: Voluntary chewing and swallowing of barium-mixed diet were video-taped(30 frames/s) for 5-10 minutes using x-ray fluoroscopy in five 7-8-month-old Yucatan minipigs. Frames of 2-5 masticatory cycles and bolus swallowing episodes from each animal were digitized using the video-analysis tool. The digitized points were the tip of SP and EG, and the midpoint of dorsal surface of TB. The reference point was the most gingival point on the distal surface of the upper last molar. An X-Y coordinate was set up in each frame to standardize the excursion ranges and direction of each structure and bolus. Previously implanted 2mm ultrasonic crystals in TB were used for calibration. All distance changes were converted to % of the given distances at rest.
Results: Distances between TB to SP, TB to EG, and EG to SP shortened at 49.21-75.01±9.69%, 4.06-25.30%±8.77%, and 5.82-26.25%±8.02 in opening, and elongated at 33.10-117.79%±35.81%, 5.41-30.18±10.68%, and 5.64-33.51±10.52% respectively in closing and power stroke during chewing. The distance between TB to SP increased immediately before swallowing, followed by a 20.14% to 60.5% decrease during swallowing. Decreased distance of 5.65% to 38.02% and 1.57% to 42.73% were observed between EG to TB and EG to SP respectively, but phasic changes of EG to TP and EG to SP were not as definitive as the change seen between SP and TB.
Conclusions: The spatial relationships of three oropharyngeal structures decrease and increase in distance and the largest changes in chewing is between TB and SP due to jaw movements. The closer spatial relationship of these three structures during swallowing propels the bolus through the oropharynx.