Contribution of the cheeks to the intraoral manipulation of food.

The role of the teeth in chewing has been studied extensively; however, less attention has been paid to soft tissue function. In this study the process of mixing within the bolus and the contribution of the cheeks to this process were investigated using a test food constructed from two differently colored chewing gums. A cheek guard was placed into either the left the or right buccal sulcus. Eighteen dentate subjects were instructed to chew four samples of gum for 30 strokes, two samples with the cheek guard in place and two without. Upon completion, the gum was removed from the mouth and its length was measured. The bolus was then placed into a plastic bag and flattened. Pairs of flattened samples chewed with and without the cheek guard in place were then assessed by five judges who were asked to identify which of each pair was most mixed. Inhibition of the cheek during chewing resulted in significantly longer samples, which were also less mixed.