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Chew Strong




Samantha Kennis

October 24, 2008




Is there more to gum than just blowing bubbles?


The obsession with chewing gum is showcased by the fact that you cannot step up to a register at any grocery store, convenience store, or pharmacy without passing an entire shelf of gum.  This seemingly new oral fixation that transcends all age groups is now being promoted by dentists and other health practitioners.  The truth is, however, that chewing gum has existed for centuries in a wide variety of forms and flavors, and ever since its invention, gum has been used for various functions.  The very first forms of gum were made of bark tar, which is thought to have antiseptic properties.  Similarly to today, ancient Mayans used gum as a mouth freshener.  Later, during World War I, gum was provided to improve soldiers’ concentration and to relieve stress (  The function of gum has ranged from a simple confectionery product to being associated with health-related outcomes and cognitive processes.  Although research is limited, it has been linked to: promoting and maintaining oral hygiene, losing weight, increasing alertness, reducing ear discomfort, whitening teeth, quitting smoking, relieving stress, and enhancing mental functioning (,

Is gum the “magic pill” we have been looking for?   


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Regardless of all of the possible benefits and disadvantages, gum has been proven to aid in oral hygiene.  Chewing gum stimulates the production and flow of saliva, which neutralizes the acids that cause tooth decay.  Moreover, the action of chewing gum removes food debris and can help remove plaque, which causes gingivitis.  These benefits are, of course, limited to sugarfree gum, as sugar will enhance the risk of oral health risks, such as cavities. (  Can gum do more than just prevent? 







The Latest Craze: Trident Xtra Care


As part of the explosion of gum for purposes other than simple enjoyment, Cadbury, the makers of Trident, launched a new line of gum called Xtra Care that strengthens teeth.  With gum companies coming out with new “long-lasting” flavors, gum that whitens teeth, and gum that makes you go from “nice gut to nice butt,” it is no wonder that the innovative uses of gum are being exploited (  Companies need to find reasons why their gum product is better than the next.  If these reasons include health benefits, then they consequently gain the support of health practitioners and consumers alike.  This marketing strategy of highlighting the advantages of chewing gum is likely to convert those that hold the traditional thought that gum is bad for your teeth.

 “They say strength comes from within.  But chewing this takes things to a whole new level.”  Rather than simply preventing tooth decay, Trident claims that chewing Xtra Care gum will actively rebuild teeth.  The ingredient Recaldent, containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), hardens tooth enamel and makes it less vulnerable to future damage.  Recaldent is a unique form of calcium that is absorbed directly into the tooth, strengthening areas attacked by plaque acids.  Trident asserts that Xtra Care gum replaces minerals to weakened tooth enamel, leaves teeth resistant to plaque acids, and promotes tooth remineralization.  Moreover, the benefits of this gum are available for up to three hours after chewing ( - /products/xtracare/coolmint). 


After a person eats, plaque bacteria produce plaque acids, which cause calcium and phosphate to leave the enamel of teeth.  A white spot lesion marks the area of weakened enamel.  Recaldent, a milk-derived ingredient in Trident Xtra Care gum consists of the milk protein, casein, calcium, and phosphate.  Casein binds to the plaque layer on the surface of the tooth and when it comes into contact with plaque acids, it releases calcium and phosphate in a soluble form.  It penetrates the enamel, rebuilding enamel from the inside out.  Since it is only absorbed in regions that need it, where the enamel is weakened, the rest will be washed away naturally by saliva.  Lastly, Trident declares that Recaldent is effective immediately, even after chewing the very first piece of gum ( - /faq/).  


The Evidence

            Amorphous calcium phosphate (ACP) has been used as a dental treatment for years, as calcium and phosphate are natural building blocks of teeth.  A complex is created with casein phosphopeptide (CPP) that binds to biofilms, plaque, and bacteria, which localizes the available calcium and phosphate to these problem areas.  In addition to strengthening tooth enamel, this treatment can reduce sensitivity, increase the flow of saliva, and protect dentine, a major component of teeth (


            One clinical study investigated the acid resistance of enamel lesions remineralized in situ by a sugarfree gum containing CPP-ACP.  This was a double-blind, randomized study with two treatments: 1) sugarfree gum containing 18.8 mg of CPP-ACP, and 2) sugarfree gum not containing CPP-ACP.  The subjects of this study wore palatal appliances with insets of human enamel containing demineralized subsurface lesions and chewed the gum for 20 minutes, four times per day, for 14 days.  After each treatment, the enamel was removed and half of each lesion was treated with acid in vitro for eight or 16 hours.  The method used to measure remineralization was microradiography, which shows the details of the tooth with high magnification.  This study found that gum containing CPP-ACP produced almost twice the level of remineralization as the control.  Additionally, after the acid was added to the enamel, there was a greater reduction of the deposited mineral in the teeth chewing the control gum than in the teeth chewing the CPP-ACP gum.  Demineralization occurred underneath the remineralized zone in both treatments, which suggests that the remineralized area was more resistant to subsequent acid challenges; however, the remineralization of enamel by gum containing CPP-ACP was more resistant to subsequent tests (Iijima, Cai, Shen, Walker, Reynolds, Reynolds, 2004).

Microradiographs of tooth lesions before and after treatment with Recaldent gum (bottom panels) show more remineralization than with an ordinary sugarfree gum (top panels).



            A similar study also found that the remineralization effects and the acid resistance of the remineralized enamel are significantly higher in gum containing CPP-ACP and citric acid (13.0 +/- 2.2%) than gum containing citric acid alone (2.6 +/- 1.3%) and the control (9.4 +/- 1.2%).  This was a double-blind, randomized study with three treatments: 1) sugar-free gum containing 20 mg citric acid and 18.8 mg CPP-ACP, 2) sugar-free gum containing 20 mg citric acid alone, and 3) sugar-free gum not containing CPP-ACP or citric acid.  Ten subjects wore palatal appliances with insets of human enamel containing demineralized subsurface lesions and chewed gum for 20 minutes, four times per day, for 14 days.  The enamel slabs were removed and half of the remineralized lesion was treated with demineralization buffer for 16 hours in vitro.  Microradiography subsequently determined the level of remineralization (Cai, Manton, Shen, Walker, Cross, Yuan, Reynolds, Reynolds, 2007).

Another study was conducted to determine the efficacy of three commercially available sugarfree gums, Trident White, Orbit, and Orbit Professional, that claim to have oral health benefits.  Samples containing enamel subsurface lesions were sectioned into test and control slabs and the test slabs were inserted into palatal appliances.  Ten subjects were randomly assigned one of the three gums and chewed for 20 minutes, four times per day, for 14 days.  Each subject chewed all three gums, with seven days in between crossovers.  Microradiography, again, determined the level of remineralization.  The Trident White showed significantly greater remineralization (18.4 +/- 0.9%) than the other two gums (8.9 +/- 0.5% and 10.5 +/- 0.9%), which can be attributed to the presence of CPP-ACP (Manton, Walker, Cai, Cochrane, Shen, Reynolds, 2008). 

Not only does Recaldent appear to be an advantageous addition to sugarfree gum, it has been found to be superior to other forms of calcium in remineralizing enamel subsurface lesions, independent of frequency and duration of gum-chewing.  Additionally, this study detected CPP in extracts taken three hours after subjects chewed the gum (Reynolds, Cai, Shen, Walker, 2003).

CPP levels in supragingival plaque detected by competitive ELISA [data presented as mean ± SD (n = 30)]. (a-d) Values significantly different (p < 0.05) from all other values not similarly marked, as shown by a one-way classification ANOVA with a post hoc Scheffé test.

( - T)


This study consisted of two randomized, double-blind, crossover studies with sugarfree gums containing different forms of calcium.  A healthcare group provided the gums and the levels of water-soluble and acid-soluble calcium phosphate of each gum were examined.  The subjects chewed the pellet gum at given times for 20 minutes, four times per day, for 14 days, while subjects chewed the slab gum for five minutes, seven times per day at given times, for seven days.  Subjects were instructed not to eat, drink, or use any forms of oral hygiene while wearing the appliances.  When the appliances were not in the subjects’ mouths, they were stored in a sealed moist bag at room temperature.  The percentage of remineralization was recorded and statistical tests were performed.  In the other study, subjects chewed two pieces of the Recaldent pellet gum three times daily for four days to determine how long CPP-ACP could be detected in plaque (Reynolds et al., 2003)

Although one study of animals and humans has shown that Recaldent has the capacity to remineralize early loss of tooth structure and reduce caries, a meta-analysis of CPP-ACP found existing data to be inconclusive with regard to its long-term effectiveness (Anonymous, 2002; Azarpazhooh & Limeback, 2008).  The meta-analysis reviewed 98 articles and ultimately found 12 relevant ones.  Nine of these were focused on caries, which is a disease that damages tooth structure and usually results in cavities or decay (  Seven of the nine studies related to caries showed that CPP-ACP was effective in remineralizing lesions in order to prevent dental caries.  Only one of these studies provided conflicting results and the others did not concern the effects of CPP-ACP in terms of remineralization and thus, are not relevant to Trident’s claims about rebuilding tooth enamel (Azarpazhooh & Limeback, 2008).  Despite the numerous studies that found significant results that support the effectiveness of CPP-ACP, the meta-analysis concluded that the quantity and quality of the clinical studies were insufficient to make conclusions. 


Spit Out Your Gum?


Gum has attracted positive attention for its present and potential uses connected to promoting health; however, controversy still remains.  Some people theorize that gum ingredients are carcinogenic, and others believe chewing gum may cause jaw problems.  Moreover, the improper disposal of gum has consequences, such as being prohibited in schools and in an extreme case, being legally banned from a country ( 

Therefore, gum companies must compete with negative attention and with each other in order to sell their product.  Luckily for consumers, this competition has led to health-promoting gum.  Sugarfree gums with additional benefits are being advertised greatly.  If dentists are supporting certain gums, then parents are presumably more likely to allow their children to chew gum and are more likely to chew gum themselves.  The claims that gum companies make, however, must be substantiated by sufficient and credible evidence. 

Many of the websites that discuss the benefits of chewing gum are related to dental care or are solely for informational purposes.  Furthermore, the experimenters of the studies presented do not appear to be affiliated with Cadbury or Trident in any way, which makes them impartial to the success of Trident Xtra Care gum sales.  The studies were performed simply for knowledge and research purposes related to oral healthcare, as many of the researchers are associated with the University of Melbourne Dental School.  Additionally, some of the studies were completed before Trident launched its new line of gum.  The number of studies performed, as well as the significance found, is enough to outweigh the fact that the studies were conducted by many of the same investigators.

The meta-analysis may have regarded the data as insufficient since the analysis was looking at the effectiveness of CPP-ACP with respect to not only in remineralization, but also hypersensitivity and dry mouth.  The results with respect to remineralization alone were shown to support the effect of CPP-ACP.  It would be interesting to see if these studies could be replicated by other sources and with more subjects, even though the limited number of subjects still produced significant results.

All of Trident’s claims, from rebuilding and strengthening enamel to its effectiveness for up to three hours after chewing, were supported by studies.  Whether or not gum can increase memory or help people lose weight and relieve stress is still uncertain, but gum has been proven to aid in oral hygiene and dental care.  Trident Xtra Care, specifically, helps to rebuild and strengthen teeth.  Chewing Trident Xtra Care gum or any gum with CPP-ACP is not a bad habit, but rather is now being advised.  Don’t be surprised if at your next visit, your dentist recommends buying a pack (of gum)! 












Anonymous. (2002). New adjunctive agent for caries control: Recaldent. Biological Therapies in

Dentistry, 18, S1.

Azarpazhooh, A., & Limeback, H. (2008). Clinical efficacy of casein derivatives: A systematic

review of the literature. Journal of the American Dental Association, 139(7), 915.

Cai, F., Manton, D.J., Shen, P., Walker, G.D., Cross, K.J., Yuan, Y., Reynolds, C., Reynolds,

E.C. (2007). Effect of addition of citric acid and casein phosphopeptide-amorphous calcium phosphate to a sugar-free chewing gum on enamel remineralization in situ. Caries Research, 41(5), 377-83. 

Iijima, Y., Cai, F., Shen, P., Walker, G., Reynolds, C., Reynolds, E.C. (2004). Acid

Resistance of Enamel Subsurface Lesions Remineralized by a Sugar-Free Chewing Gum Containing Casein Phosphopeptide-Amorphous Calcium Phosphate. Caries Research, 38(6), 551-56.

Manton, D.J., Walker, G.D., Cai, F., Cochrane, N.J., Shen, P., Reynolds, E.C. (2008).

Remineralization of enamel subsurface lesions in situ by the use of three commercially available sugar-free gums. Int J Paediatr Dent., 18(4), 284-90.

Reynolds, E.C., Cai, F., Shen, P., Walker, G.D. (2003). Retention in plaque and remineralization

of enamel lesions by various forms of calcium in a mouthrinse or sugar-free chewing gum. J Den Res., 82(3), 206-11.



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