Potential benefits of chewing gum for the delivery of oral therapeutics and its possible role in oral healthcare

Figures & data

Table 1. Overview of chewing gum ingredients with their functions and estimates of percentages [14–16].

Ingredient	Percentage	Function	Examples
Elastomers	Up to 45%	Natural or synthetic elastomers provide the elastic feel to the gum	Chicle (natural), polyisobutylene, polyvinylacetate (synthetic)
Resins	Up to 70%	Provides softening of the elastomers	Natural rosin esters or terpene resins
Waxes	Up to 30%	Softens the gumbase mixture and improves characteristics of chewing	Petroleum or natural waxes
Fillers	Up to 60%	Modifies the texture of the gum	Talc, calcium carbonate
Emulsifiers	Up to 45%	Mixing normally immiscible ingredients, reduces stickiness	Glycerol monostearate
Softeners	Up to 15%	Changes the texture of the gum, aids in blending ingredients	Glycerin, cocoa butter
Antioxidants	0.10%	Prolong storage and shelf life	Butylated hydroxyanisole, vitamin C
Sweeteners	Up to 60%	Adds flavor and sweetness	Conventional sugars (30–60%) or sugar substitutes (0.02–8%)
Flavors	0.01–1%	Adds various flavorings	Essential oils

Table 2. Overview of active ingredients used in different chewing gums and oral health benefits as reported in the literature, including EFSA support of specific claims where available.

Active ingredient	Effect	Remarks	EFSA support	References
None (basic effects of regular sugar-free gum)	Reduction of oral dryness	Chewing of gum can relieve dry mouth symptoms during chewing	Yes	[22,24]
	Clearance of food debris	Chewing gum increases rate of clearance of food debris; it removes sources of fermentable sugars	–	[25,26]
	Inhibition of extrinsic tooth stain	Chewing at least 4 times 15 min per day for 4 weeks or longer reduces extrinsic tooth stain	–	[12,38]
	Reduction of VSCs	Chewing gum temporarily freshens breath by reducing VSCs after chewing	–	[13]
	Neutralization of biofilm pH	Increased salivation neutralizes biofilm pH	Yes	[24,54,55]
	Remineralization of enamel	Saliva is saturated with minerals increasing remineralization	Yes	[10,24,66]
	Reduction of oral biofilm	Preventing biofilm regrowth at occlusal surfaces when refraining from oral hygiene for 4 days. No biofilm reduction at other tooth surfaces	No	[101,102,105]
	Caries prevention	Reduced caries incidence over 2–3 years when using 2–3 g of gum for 20 min directly after meal	Yes	[24,55,63,64,66]
Bicarbonate	Neutralization of biofilm pH	Biofilm pH elevated faster by chewing bicarbonate gum after sucrose challenge	–	[58,59]
Calcium	Remineralization of enamel	In situ studies show short-term increased remineralization. No additional caries preventive effect	No	[67,68,71]
Carbamide	Neutralization of biofilm pH	Concentration-dependent rise in biofilm pH. At least 20 mg per piece for 20 min directly after a meal. No additional caries preventive effect	Yes	[60–62]
Chitosan	Reduction of planktonic bacteria in saliva	Reduces total number of oral bacteria in saliva directly after chewing and increases salivary secretion compared to a control gum	–	[94,96]
Chlorhexidine	Reduction of planktonic bacteria in saliva	Decrease of levels of salivary mutans streptococci directly after chewing	–	[93]
	Reduction of oral biofilm	Biofilm growth was inhibited when refraining from oral hygiene for 4 days	–	[108,109]
	Increased gingival health	Significant reduction in gingival index compared to control gum after 1 year use	–	[109,110]
CPP-ACP	Remineralization of enamel	In situ studies show short-term increased remineralization	–	[74,75]
	Caries prevention	Large-scale 2-year study shows 18% less chance of tooth surface progressing to caries when chewing CPP-ACP 3 times per day compared to control gum	–	[76]
Eucalyptus	Reduction of bacteria producing VSCs	Decrease in organoleptic score and VSCs after a 14-week use compared to control gum	–	[52]
	Reduction of oral biofilm	Biofilm formation was significantly reduced compared to control gum when refraining from oral hygiene for 4 days	–	[121]
	Increased gingival health	Beneficial effect on probing depth and gingival bleeding after 12 weeks use	–	[123]
Fluoride	Remineralization of enamel	General fluoride claims also apply on fluoridated chewing gum. Effective in case other ways of administrating fluoride are not possible	Yes	[81–83]
Magnolia bark extract	Reduction of planktonic bacteria in saliva	Reduction of total salivary bacteria and mutans streptococci directly after chewing and after 30 days of use	–	[51,86]
	Reduction of bacteria producing VSCs	Reduction of VSCs directly after chewing and in vitro effectiveness against bacteria responsible for oral malodor	–	[51,53]
Mastic	Reduction of planktonic bacteria in saliva	Reduction of total salivary bacteria and salivary mutans streptococci directly after chewing compared to control gum	–	[95,122]
	Reduction of oral biofilm	Inhibition of biofilm formation when refraining from other oral hygiene for 7 days compared to control gum	–	[122]
Polyols–xylitol	Reduction of planktonic bacteria in saliva	When used for 5 weeks xylitol gum is more effective in reducing salivary mutans streptococci than a control gum. No change in biofilm composition was observed	–	[87,118]
	Neutralization of biofilm pH	Neutralization of biofilm pH was observed after long-term use (6 months)	No	[57]
	Caries prevention	Valid when 100% xylitol gum is used 3 times per day in high dose (≥6 g/day)	Yes	[89,90,115]
Polyphosphates	Inhibition of calculus formation	Calculus reduction supragingivally, not at sites which matter most for gingival health (gingival margin, interproximal spaces)	No	[34,36]
	Inhibition extrinsic tooth stain	Stain inhibition within 2 days when chewed 8 times per day. With 3 times per day stain inhibition was shown after 6 weeks	–	[39,40,43]
Propolis	Reduction of planktonic bacteria in saliva	Significant decrease of salivary Streptococcus mutans counts directly after chewing compared to a xylitol gum	–	[97]
Vitamin C	Inhibition of calculus formation	Reduction of supragingival calculus formation compared to no chewing when used 5 times per day for 3 months	–	[33]
Zinc	Reduction of VSCs	Reduction of VSCs directly after chewing comparable to zinc mouthrinse	–	[50]

EFSA: European Food Safety Authority; VSC: volatile sulfur compound; CPP-ACP: casein phosphopeptide - amorphous calcium phosphate.

Figure 1. Basic effects of the chewing of regular sugar-free gum on oral health are displayed in the inner ring, and are predominantly due to increased mastication and salivation. Potential effects of active ingredients used in chewing gum on oral health are displayed in the outer ring, of which some are an extension of the effects of regular sugar-free gum.

Figure 2. Removal of food debris (Oreo cookie, Nabisco, East Hanover, NJ, USA) from lower jaw occlusal surfaces by the chewing of gum (TOP row) and by natural oral cleansing mechanisms only without chewing of gum (BOTTOM row). A photograph was taken before consumption (LEFT column) and directly after consumption (MIDDLE column). Subsequently, the volunteer was requested to chew regular sugar-free gum for 2 min (TOP row) or wait for 2 min without the chewing of gum (BOTTOM row) and a third photograph was taken afterwards, illustrating the difference in removal of food debris (RIGHT column). Photographs taken with thanks to the Department of Orthodontics, University Medical Center Groningen, The Netherlands.

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