Sucrose, a disaccharide, is commonly used in chewing gum. Sucrose and other fermentable carbohydrates can be metabolized by oral bacteria. These bacteria (particularly S. mutans and Lactobacillus spp.) produce dental biofilm and acid, which can lead to enamel demineralization and caries.The potential cariogenicity of sugar-containing gum depends on the physical consistency, oral retention time of the gum, the frequency with which it is chewed, and the sequence of consumption (for instance, chewing sugar-containing gum before eating foods that reduce acid production will be less cariogenic than the reverse).Chewing gum can be labeled as “sugar-free” if it contains less than 0.5 g of sugars per serving.In place of sugar, high-intensity sweeteners such as acesulfame-K, aspartame, neotame, saccharin, sucralose or stevia are used to sweeten gum.Gum may also be sweetened with sugar alcohols such as erythritol, isomalt, maltitol, mannitol, sorbitol, or xylitol.Unlike sugar, these sweeteners are noncariogenic, since they are metabolized slowly or not at all by cariogenic plaque bacteria.These sweeteners contain fewer calories than sugar, but the U.S. Food and Drug Administration (FDA) considers aspartame and all of the aforementioned sugar alcohols to be nutritive sweeteners since they contain more than 2% of the calories in an equivalent amount of sugar.Chewing gum can decrease plaque pH if it contains acids for flavoring (e.g., citric acid) or via bacterial production of acids if the gum contains sugars. The critical value for enamel dissolution is pH of 5.5.When the pH of plaque drops below this critical value, enamel demineralization occurs and a caries lesion may form.Gum with a pH lower than 5.5 may contribute to enamel erosion.The average unstimulated salivary flow rate for healthy people is 0.3-0.4 mL/min.The physical act of chewing stimulates salivary flow: simply chewing unsweetened, unflavored chewing gum base stimulates the salivary flow rate by 10-12 times that of the unstimulated rate.Flavors also act as salivary stimulants.The stimulated salivary flow rate is significantly greater while chewing sweetened and flavored gum as opposed to unsweetened, unflavored chewing gum base.Stimulated saliva flow provides protection against dental erosion via several mechanisms. Saliva buffers the effects of acids in foods or drinks that could otherwise soften teeth’s enamel surface, and swallowing excess saliva created by stimulation clears acid.While unstimulated saliva does not have a strong buffering capacity against acid, stimulated saliva has higher concentrations of total protein, sodium, total calcium, chloride, and bicarbonate and therefore has a higher buffering capacity.Additionally, saliva contributes proteins to dental surfaces, creating an acquired enamel pellicle that protects against dental erosion.Stimulating salivary flow also enables clearance of fermentable carbohydrates, thereby removing them before bacteria in dental plaque can metabolize them.This mechanism, combined with the aforementioned protection against dental erosion, are possible reasons why clinical trials have found decreased caries incidence in subjects who chewed sugarless gum for twenty minutes after meals.Since chewing gum increases salivary flow, it can also assist in acid clearance in the esophagus via that increase in secretion and swallowing. Gum chewing may reduce symptoms for those with gastroesophagealor laryngopharyngeal reflux conditions.Chewing sugar-free gum is also an effective method of treating symptoms of dry mouth among those with residual secretory capacity.A systematic review found that sugar-free chewing gum improved subjective symptoms of dry mouth commensurate with other saliva stimulants and substitutes, but does not have a long-term effect on saliva production.There is no evidence that any one specific type of gum is superior in this respect.Chewing gum is an adjunct to brushing and flossing, but not a substitute for either.The ADA recommends brushing twice a day with a fluoride toothpaste and cleaning plaque from between the teeth once a day with dental floss or other interproximal dental cleaners.