Chewing chewing, the food (now called a bolus) is swallowed. It enters the esophagus and via peristalsis continues on to the stomach, where the next step of digestion occurs. Premastication is sometimes performed by human parents for infants who are unable to do so for themselves. The food is masticated in the mouth of the parent into a bolus and then transferred to the infant for consumption. (Some other animals also premasticate.) Cattle and some other animals, called ruminants, chew food more than once to extract more nutrients. After the first round of chewing, this food is called cud. Chewing is
Chewing gum upon enamel that has been reduced by adding calcium lactate to food. Calcium lactate added to toothpaste has reduced calculus formation. One study has shown that calcium lactate enhances enamel remineralization when added to xylitol-containing gum, but another study showed no additional remineralization benefit from calcium lactate or other calcium compounds in chewing-gum. Other studies indicated that the caries preventive effect of chewing sugar-free gum is related to the chewing process itself rather than being an effect of gum sweeteners or additives, such as polyols and carbamide. A study investigated the in situ effect of casein phosphopeptide–amorphous calcium phosphate (CPP–ACP)