Chewing Gum

Chewing gum in various forms has been around since ancient times.¹ The Greeks chewed sap from the mastic tree, called mastiche. The ancient Mayans favored the sap of the sapodilla tree (called tsiclte). Native Americans from New England chewed spruce sap—a habit they passed on to European settlers. Today, the base used for most gum products is a blend of synthetic materials (elastomers, resins and waxes in various proportions), flavors, colors, and sweeteners.² A category of the ADA Seal of Acceptance recognizes chewing gum that has demonstrated that it can help protect the teeth.

Sugar-containing Chewing Gum
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.³ 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).³

Sugar-free Chewing Gum
Chewing gum can be labeled as “sugar-free” if it contains less than 0.5 g of sugars per serving.⁴ In place of sugar, high-intensity sweeteners such as acesulfame-K, aspartame, neotame, saccharin, sucralose or stevia are used to sweeten gum.² Gum may also be sweetened with sugar alcohols such as erythritol, isomalt, maltitol, mannitol, sorbitol, or xylitol.² Unlike sugar, these sweeteners are noncariogenic, since they are metabolized slowly or not at all by cariogenic plaque bacteria.⁵ 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.⁶

Acid
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 5.5.³ When the pH of plaque drops below this critical value, enamel demineralization occurs and a caries lesion may form.³ Gum with a pH lower than 5.5 may contribute to enamel erosion.

Salivary Flow
The average unstimulated salivary flow rate for healthy people is 0.3-0.4 mL/min.⁷ 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.⁸ Flavors also act as salivary stimulants.⁷ The stimulated salivary flow rate is significantly greater while chewing sweetened and flavored gum as opposed to unsweetened, unflavored chewing gum base.^{8, 9}

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.¹⁰ 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.⁷ Additionally, saliva contributes proteins to dental surfaces, creating an acquired enamel pellicle that protects against dental erosion.^{7, 10}

Stimulating salivary flow also enables clearance of fermentable carbohydrates, thereby removing them before bacteria in dental plaque can metabolize them.⁷ 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.^{11, 12}

Other Effects of Chewing Gum
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 gastroesophageal^{13, 14} or laryngopharyngeal reflux conditions.¹⁵

Chewing sugar-free gum is also an effective method of treating symptoms of dry mouth among those with residual secretory capacity.¹⁶ 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.¹⁶ There is no evidence that any one specific type of gum is superior in this respect.¹⁶

Does Chewing Gum Replace Brushing and Flossing?
Chewing gum is an adjunct to brushing and flossing, but not a substitute for either.¹⁷ 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.

Look for the ADA Seal—your assurance that the product has been objectively evaluated for safety and efficacy by an independent body of scientific experts, the ADA Council on Scientific Affairs.

A company earns the ADA Seal by demonstrating that its product meets the requirements for safety and efficacy for sugar-free chewing gum. Studies must also show that the gum is safe for use in the oral cavity. The manufacturer must provide the results of both laboratory studies and clinical studies in humans.

Does the ADA award its Seal to sugar-containing gum?
Only chewing gums that are sugar-free can be considered for the ADA Seal. They are sweetened by non-cavity-causing sweeteners such as aspartame, sorbitol or mannitol. Chewing sugar-free gum has been shown to increase the flow of saliva, thereby reducing plaque acid, strengthening the teeth and reducing tooth decay.

1. Fiegl A. A Brief History of Chewing Gum. Smithsonian.com: Smithsonian 2009.
2. International Chewing Gum Association. The Science and Technology Behind Chewing Gum Ingredients. Accessed March 26, 2019.
3. Touger-Decker R, van Loveren C. Sugars and dental caries. Am J Clin Nutr 2003;78(4):881S-92S.
4. U.S. Food and Drug Administration. Code of Federal Regulations Title 21, Specific Requirements for Nutrient Content Claims. 2017. 2019.
5. Burt BA. The use of sorbitol- and xylitol-sweetened chewing gum in caries control. J Am Dent Assoc 2006;137(2):190-6.
6. U.S. Food & Drug Administration. Additional Information about High-Intensity Sweeteners Permitted for Use in Food in the United States. 2018.
7. Dawes C, Pedersen AM, Villa A, et al. The functions of human saliva: A review sponsored by the World Workshop on Oral Medicine VI. Arch Oral Biol 2015;60(6):863-74.
8. Dawes C, Macpherson LM. Effects of nine different chewing-gums and lozenges on salivary flow rate and pH. Caries Res 1992;26(3):176-82.
9. Polland KE, Higgins F, Orchardson R. Salivary flow rate and pH during prolonged gum chewing in humans. J Oral Rehabil 2003;30(9):861-5.
10. Buzalaf MA, Hannas AR, Kato MT. Saliva and dental erosion. J Appl Oral Sci 2012;20(5):493-502.
11. Stookey GK. The effect of saliva on dental caries. J Am Dent Assoc 2008;139 Suppl:11S-17S.
12. Mickenautsch S, Leal SC, Yengopal V, Bezerra AC, Cruvinel V. Sugar-free chewing gum and dental caries: a systematic review. J Appl Oral Sci 2007;15(2):83-8.
13. von Schonfeld J, Hector M, Evans DF, Wingate DL. Oesophageal acid and salivary secretion: is chewing gum a treatment option for gastro-oesophageal reflux? Digestion 1997;58(2):111-4.
14. Moazzez R, Bartlett D, Anggiansah A. The effect of chewing sugar-free gum on gastro-esophageal reflux. Journal of dental research 2005;84(11):1062-65.
15. Smoak BR, Koufman JA. Effects of gum chewing on pharyngeal and esophageal pH. Ann Otol Rhinol Laryngol 2001;110(12):1117-9.
16. Furness S, Worthington HV, Bryan G, Birchenough S, McMillan R. Interventions for the management of dry mouth: topical therapies. Cochrane Database Syst Rev 2011(12):CD008934.
17. Imfeld T. Chewing gum—facts and fiction: a review of gum-chewing and oral health. Crit Rev Oral Biol Med 1999;10(3):405-19.

What products have earned the ADA Seal of Acceptance?
Get a Complete List of ADA Accepted Chewing Gum

Additional Resources

• JADA “For the Patient” pages:  Eating habits for a healthy smile and body and Sealing the deal: Buying products that have the ADA Seal of Acceptance
• ADA MouthHealthy: Chewing Gum to Prevent Cavities