2006 Volume 10 Issue 1 Pages 62-71
【Objective】We divided the feeding process depending on the location of bolus．We analyzed the chewing cycle of each swallowing stage，to investigate the cooperation between mastication and swallowing movement．
【Method】Twelve healthy adults (average age，28.8 ± 3.7y) having normal occlusion participated in this study．Subjects were instructed to eat 8g of cookies containing barium，and then jaw and bolus movements during mastication and swallowing were recorded simultaneously．Bolus transportation was recorded by videofluorography from a lateral view，and the jaw cycle was recorded by digital video from the antero-posterior view．The swallowing stage was divided into four stages，as follows： In Stage 1 transport，food is moved to the molar region； in Processing，food is manipulated to bolus in the mouth； in Stage 2 transport，bolus is propelled into the oropharynx during chewing，and hypopharyngeal transit time is the pharyngeal stage of swallowing．All of the subjects were classified into two groups according to the types of chewing cycle： ln Type 1 (n＝3)，lateral jaw displacement during mastication is larger than vertical displacement； in Type 2 (n＝9)，lateral jaw displacement is smaller than vertical．Maximum gape，cycle breadth： maximum breadth of the chewing loop； duration of the chewing cycle； duration of each swallowing stage，and the rate of duration of each swallowing stage，were compared by each type of chewing cycle．
【Results】The duration of Processing of Type 1 was shorter than that of Type 2．In Type 1，neither the duration nor the chewing cycle changed between Processing and Stage 2 transport．In Type 2，the maximum gape and the duration of Stage 2 transport were shorter than those of Processing．
【Discussion】There are two patterns of coordination of jaw movement and food transport．That is Stage 2 transport with or without reduction of jaw movement according to the progress of mastication．Therefore，it was suggested that the food transportation and bolus formation was different when the chewing cycle pattern was different．
