Written evidence submitted by Wrigley (COH0024)

Summary

1. The incidence of tooth decay has been greatly reduced in many countries following the adoption of fluoride-containing dentifrices, fluoride added to drinking water, and sustained promotion of consistent dental hygiene practices, including regular visits to the dentist for a dental health check and prophylaxis.  However, even with these advances, the incidence of tooth decay remains frustratingly high in countries in which they have been implemented.  For example, in the most recent survey, Public Health England reported that approximately 27% of 5 year old children have tooth decay (Ref. 1).  While this figure represents substantial improvement over time, additional improvement is certainly within reach.  In the United States, 42% of children between ages 2 and 11 years have dental caries (Ref. 2).  In Canada, 57% of children between the ages of 6 and 11 years have dental caries.  In the surveys from the U.S. and Canada, the incidence increased with age (Ref. 3).  These surveys represent significant progress, made over decades, and also significant potential for additional progress.  The chewing of sugarfree gum after eating and drinking occasions represents a potential adjunct strategy for promoting dental health which has earned increasing recognition over time. 

2. In the UK, official oral care guidance has rarely explicitly mentioned sugarfree gum. However the evidence described above as well as the fact that the recently published draft report from the Scientific Advisory Committee on Nutrition states that “randomised controlled trials indicate that the use of chewing gum containing sugar alcohols reduces risk of dental caries, as compared with not using a chewing gum, but it is unclear whether it is specifically the sugar alcohols or the act of chewing and the concomitant increase in salivary flow that contributed to the effect.” (Source, Pg. 105 Para. 6.78) together suggest that the potential benefits of including sugarfree gum in preventative oral health advice should be considered.

3. This document gives an overview of available evidence for sugarfree gum with studies given in full as additional attachments.

The Action of Sugarfree Gum to remove carbohydrate, sugar, and food debris residues

4. Normal unstimulated or resting saliva flow is about 0.5ml/minute.  Initial flow rates during chewing are about 10 times (5-6 ml/min) higher than resting rates.  Even after chewing for 20 minutes the flow rate is 3 times higher than the normal resting rate because the glands can maintain long-term production of saliva (Refs. 8-10).

5. The stimulation of saliva flow by chewing gum has been found to be significant in the clearance of both liquids such as glucose, and foods, such as debris from a mixed meal, licorice candy, and a biscuit (cookie), as measured by the amount of food debris that is cleared from the dentition (Refs. 11 -13).  For example, chewing sugarfree gum shortened glucose clearance time by 49% (Ref. 11) and removed between 80 and 90+% of biscuit (cookie) debris within 2 minutes (Ref.13).

Plaque pH after consuming foods containing sugars or starches

6. Most eating occasions include ingestion of carbohydrates (Ref. 14) which typically include mono-, di- and polysaccharides such as glucose, fructose, sucrose, glucose syrups and starches.  These carbohydrates can be fermented by the oral microflora found in the plaque and tissues in the mouth and produce organic acids such as lactic and acetic acids.  In turn, these acids can dissolve tooth enamel when the pH falls below the ‘critical pH’ of approximately 5.5 (Ref.15).

7. It is difficult to avoid foods that contain carbohydrates, and such a recommendation would be contrary to accepted dietary guidelines, such as the dietary guidance to base meals on starchy foods found in Delivering Better Oral Health: An evidence- based toolkit for prevention (Ref 16).  Thus, the strategy of reducing the duration of exposure of the teeth to acid is a well-accepted dental health concept.  Dentists recommend avoiding frequent snacking in order to reduce the number of acidogenic exposures.  This principle is based on the finding that frequency of dietary carbohydrate challenges was associated with the incidence of caries (Ref. 17).  However, the type and amount of dietary carbohydrates have also been suggested as factors in the caries process.  This is acknowledged by the U.S. Food and Drug Administration in the approved health claim for noncariogenic sweeteners, which includes the following statement: “The relationship between consumption of fermentable carbohydrates, i.e., dietary sugars and starches, and tooth decay is well established. Sucrose, also known as sugar, is one of the most, but not the only, cariogenic sugars in the diet. Bacteria found in the mouth are able to metabolize most dietary carbohydrates, producing acid and forming dental plaque. The more frequent and longer the exposure of teeth to dietary sugars and starches, the greater the risk for tooth decay.” (Ref.18)

Neutralisation of plaque acids

8. A fall in plaque pH occurs after exposure to carbohydrate.  Stimulated saliva flow produces saliva with an increased concentration of bicarbonate, from 3-4 mmol/l to 15 mmol/l or higher (Ref. 7).  This increase in bicarbonate provides an effective system to buffer plaque acids, thereby increasing the pH in a few minutes and keeping the pH neutral long after gum chewing is stopped. 

9. The reversal of this fall in plaque pH by chewing sugarfree gum, has been regarded as evidence of a mechanism for reduction in caries risk. A body of 18 clinical studies on the effect of chewing sugarfree gum on plaque pH are summarized in Table 1 (Ref. 19-35).

10. The results of these 18 studies demonstrate the rapid and sustained plaque acid neutralisation which occurs when sugarfree gum is chewed after an acid response to carbohydrate exposure. The consistency of these findings has been reflected in a statement on noncariogenic sweeteners (FDA; Ref 18), three expert reviews (Ref. 47-49), and the proceedings report from an expert consensus meeting (Ref. 38).  A health claim based upon the plaque pH neutralizing effect of sugarfree gum was positively reviewed by the European Food Safety Authority (EFSA) and has been approved for use in the EU (Ref. 66).  A second, separate health claim, specifically based these 18 clinical studies on the effect on plaque pH and on the clinical studies which demonstrated reduced incidence of dental caries was also positively reviewed by the EFSA and approved for use in the EU, indicating that a rigorous review of the totality of the evidence supports the plaque pH neutralizing effect of chewing sugarfree gum (Ref. 39).

Table 1.  Studies of plaque pH neutralization by sugarfree gum*

*Please note:  These studies above are listed in a different order than references 17 and 33.

Demineralisation and enhanced remineralisation

11. If the plaque pH is lowered and remains low for extended and/or frequent periods of time, this condition favors the demineralization of enamel.  The initial, reversible lesions are clinically described as white spots (Ref. 36, 47, 48). 

12. Stimulated saliva is saturated with the same calcium, phosphate, and hydroxyl ions that make up the minerals in the enamel structure of teeth (hydroxyapatite).  Typical salivary levels are 1-2 mmol/l for calcium, 2-5 mmol/l for phosphate and 1 mmol/l for fluoride (Ref. 7).  This effect from chewing sugarfree gum shifts the equilibrium such that minerals can be deposited back into the tooth surface.  This process can result in the remineralising of early lesions and strengthening the tooth surface.  The studies results regarding this effect (Ref. 40-46) are summarized in the Table 2 on the following page.  The consistent findings for the remineralisation effect from this body of clinical studies have been recognized in published expert reviews (Ref. 47-49). 

13. A review of the evidence that chewing sugarfree gum remineralises tooth enamel (which is stated as maintaining tooth mineralisation) resulted in an authorized health claim in the EU (Ref. 50). In a review of a second, separate claim, EFSA reviewers also found that studies of the effect of sugarfree gum on the incidence of dental caries demonstrated the remineralising effect of gum chewing (Ref.66).  In the opinion, the panel wrote “In weighing the evidence, the Panel took into account that almost all of the clinical trials of sugarfree chewing gum consumption showed reduced tooth demineralisation as indicated by a reduction in caries incidence, and that there was strong evidence supporting the biological plausibility for the effect. “   

Table 2.  Studies of the remineralisation of tooth enamel by sugarfree gum*

Helps prevent dental caries

14. The most solid scientific evidence for the caries reduction effect comes from long term clinical trials in which the incidence of cavities was measured in the normal environment for subject groups that chewed sugarfree gum vs. non-chewers (Ref. 51-63).  The caries-protective effect of sugarfree gum has been recognized in two positive opinions for health claims issued by EFSA, as mentioned earlier in this document.  Separately, two systematic reviews have reached a similar conclusion (Refs. 64, 65)  Please note that if a study included more than one intervention group, there is a row for each intervention group in the study. 

Table 3.  Studies of the reduced incidence of caries due to sugarfree gum.*

*Please note:  These studies are listed in a different order in the references.

Endorsements and Acknowledgements

15. After a thorough review of the supporting evidence, The World Dental Federation (FDI) has endorsed sugarfree gum.  In the letter of endorsement, FDI included a recognition statement, which read:

“Chewing sugarfree gum is proven to benefit dental health, as it helps neutralize plaque acids.”

This statement directly acknowledges the benefit of sugarfree gum to dental health.  (Ref. 67) 

16. In the U.S., the American Dental Association (ADA) has also acknowledged the dental health effects of sugarfree gum.  The following statement excerpted from the ADA web page about chewing gum summarizes the ADA’s findings:

"The physical act of chewing increases the flow of saliva in your mouth.  If you chew after eating, the increased salivary flow can help neutralize and wash away the acids that are produced when food is broken down by the bacteria in plaque on your teeth.  Over time, acid can break down tooth enamel, creating the conditions for decay.  Increased saliva flow also carries with it more calcium and phosphate to help strengthen tooth enamel. Clinical studies have shown that chewing sugarless gum for 20 minutes following meals can help prevent tooth decay.” (Ref. 68)

17. Similarly, the British Dental Health Foundation has acknowledged the protective role of sugarfree gum, based on the strength of the supporting evidence that sugarfree gum helps to maintain dental health (Ref. 69).

18. As cited earlier, four health claims for sugarfree gum have been approved for use in the EU, following a review of the supporting evidence by the European Food Safety Authority (EFSA).   Two of these claims specifically addressed the reduction of risk of dental caries with the use of sugarfree gum (Refs 39, 50), while two additional claims were approved, one specifically on the benefit of neutralizing plaque acids and one on the benefit of remineralising tooth enamel Ref (66).

19. Most recently, Health Canada has authorized a health claim regarding the protective effect of chewing sugarfree gum regarding dental caries (Ref. 70).

20. In summary, sugarfree gum has been demonstrated to have benefits which can reduce the incidence of dental caries.  Importantly, the clinical trials which directly addressed the effect on dental caries were conducted with existing oral hygiene practices in place.  Therefore, the role of sugarfree gum for oral health is in the context of having current oral hygiene practices, such as regular tooth brushing, flossing, and regular dental visits, in place.  Sugarfree gum can be an effective addition to these essential practices.

References:

1.       Public Health England.  Survey finds 27% of 5 year olds have tooth decay.  Found at https://www.gov.uk/government/news/survey-finds-27-of-5-year-olds-have-tooth-decay

2.       Centers for Disease Control.  Preventing Chronic Diseases: Investing Wisely in Health. Preventing Dental Caries. Atlanta, Georgia. 2006. 

3.       Health Canada.  Report on the Findings of the Oral Health Component of the Canadian Health Measures Survey 2007-2009.  2010.

4.       Mouton, C.  The Efficacy of Gum Chewing and Xylitol to Reduce Oral Glucose Clearance Time, J. Can. Dent. Assn., 9: 655-660, 1983.

5.       Triolo, P.; Jensen, M.  Effect of Chewing Gum on Food Clearance from the Dentition. J. Dental Res. 69: Abstract #220, 1990.

6.       Addy, H.: Perriam, E. Sterry, A.  Effects of Sugared and Sugarfree  Chewing Gum on the Accumulation of Plaque and Debris on the Teeth. J. Clinical Periodontology, 9: 346-54, 1982

7.       Shannon, L.L.; Frome, W.J.  Enhancement of Salivary Flow Rate and Buffering Capacity. J. Can. Dent. Assn. 3:177-81, 1973

8.       Dawes, C., MacPherson, L.M.D.     Effects of Nine Different Chewing-Gums and Lozenges on Salivary Flow Rate and pH. Caries Research 26:176-182, 1992. 

9.       Dawes, C., MacPherson, L.M.D.   Salivary Flow Rate and Sugar Clearance from Different Chewing Gums. Caries Research 25: No. 1: Abstract #46, 1991.

10.   Polland, K. E., Higgins, F., Orchardson, R. Salivary Flow Rate and pH During Prolonged Gum Chewing in Humans. J. Oral Rehabilitation 30:861-865, 2003

11.   Mouton C.  The Efficacy of Gum Chewing and Xylitol to Reduce Oral Glucose Clearance Time, J. Can. Dent. Assn., 1983;9: 655-660.

12.   Triolo P, Jensen M.  Effect of Chewing Gum on Food Clearance from the Dentition. J. Dental Res., 1990;69: Abstract #220.

13.   Fu Y, Li X, Ma H, Yin W, Que K, Hu D, Dodds MWJ, Tian M.  Assessment of chewing sugarfree gums for oral debris reduction:  A randomized controlled crossover clinical trial. Am J Dent 2012;25:118-122

14.   Morgan, K.J.; Zabik, M.E.; Leveille, G.A. Food Behavior of Children:  Consumption Patterns and Nutrient Composition of Breakfasts, Snacks, and Total Day.  Research Report 374 from the Michigan State University Agricultural Experiment Station East Lansing,1978.

15.   Imfeld, T.N. Identification of Low Caries Risk Dietary Components. Monogr Oral Sci. 11:1-198, 1983

16.   Delivering Better Oral Health:  An evidence-based toolkit for prevention, 2nd edition.  Department of Health and British Association for the Study of Community Dentistry, 2009.

17.   Gustafsson, B.E., Quensel, C.E.; Lanke, L.S.; Lundqvist, C.; Grahnen, H.; Bonow, B.E.; Krasse, B.   The Vipeholm Dental Caries Study; The Effects of Different Levels of Carbohydrate Intake on Caries Activity in 436 Individuals Observed for Five Years.  Acta Odontol. Scand. 11(3-4): 232-64, 1954.

18.   Health claims: dietary noncariogenic carbohydrate sweeteners and dental caries.  21CFR101.80.

19.   Abelson DC, Barton J, Mandel ID. The effect of chewing sorbitol-sweetened Gum on salivary flow and cemental plaque pH in subjects with low salivary flow.  J Clin Dent 2; 3-5, 1990.

20.   Dodds MWJ, Hsieh SC, Johnson DA.  The effect of increased mastication by daily gum-chewing on salivary gland output and dental plaque acidogenicity.  J Dent Res 70; 1471-1478, 1991. 

21.   Dong Y, Pan Y, Wang D, Cao C.  Effect of sugarless chewing gum on dental plaque pH in situ after the mouth is rinsed with sucrose solution.  China Stomatology J, 38; , 2003.

22.   Fröhlich S, Maiwald, HJ, Flowedew, G.  Effect of Gum Chewing on the pH of Dental Plaque. Jour.Clin. Dent. 1992; 3: 75-78.

23.   Gopinath VK, Tandon S, Shirwaikar A.  The effect of chewing gums on acidogenicity of plaque after a sucrose challenge.  J Clin Pediatric Dent 22; 77-81, 1997.

24.   Jensen M.E.  Responses of Interproximal Plaque pH to Snack Foods and Effect of Chewing Sorbitol- Containing Gum. JADA. 1986; 113: 262-266.

25.   Jensen ME, Wefel, JS.  Human Plaque pH Responses to Meals and the Effects of Chewing Gum. Br. Dent. Jour. 1989; 167: 204-208.

26.   Jensen, ME.  Effects of Chewing Sorbitol Gum on Salivary and Interproximal Plaque pH. Jour. Clin. Dent. Vol. 1988; 1: 6-19.

27.   Lee IK, Schachtele CF.  Effect of Gum Chewing Following Food Ingestion on the pH of Interproximal Dental  Plaque. Quintessence Int. 1992; 23:  455-459.

28.   Maiwald H.J., Banoczy, S., Tietze W., Toth Z., Vegh  A.  Controlling Plaque pH by Sugar-Containing And Sugarfree Chewing Gum.  Zahn, Mund U. Kleferheilked. 1982; 70: 598-604.

29.   Manning RH, Edgar WM.  pH Changes in Plaque After Eating Snacks and Meals, and Their Modification By Chewing Sugared or Sugarfree Gum. British Dent. Jour. 1993; 174: 241-244.

30.   Markovic N, Abelson DH, Mandel ID.  Sorbitol gum in xerostomics the effects on dental plaque and salivary flow rates.  Gerodontology 7; 71-75, 1988.

31.   Park KK, Hernandez D, Schemehorn BR, Katz BP, Stookey GK, Sanders PG, Butchko HH.  Effect of chewing gums on plaque pH after a sucrose challenge.  ASDC J Dent Child. 1995 May-Jun;62(3):180-6.

32.   Park KK, Schemehorn BR, Bolton JW, Stookey GK.  Effect of Sorbitol Gum Chewing on Plaque pH Response after Ingesting Snacks Containing Predominantly Sucrose or Starch. Amer. J. Dent. 1990;3:185-91.

33.   Park KK, Schemehorn BR, Bolton JW, Stookey GK.  The Impact of Chewing Sugarless Gum on the Acidogenicity of Fast-Food Meals. Amer. Jour. Dent. 1990; 3: 231-35. Park KK, Schemehorn BR, Stookey GK.  Effect of Time and Duration of Sorbitol Gum Chewing on Plaque Acidogenicity. Pediatric Dentistry. 1993; 15:  197-202.

34.   Shu C-B, Tao D-Y, Wang S, Feng X-P. Effect of Two Kinds of Chewing Gums on Dental Plaque pH.  Shanghai J. Stomatol. 2007;16:172-175.

35.   Yankell SL, Emling R.C.  Clinical Study to Evaluate the Effects of Three Marketed Sugarless Chewing Gum  Products on Plaque pH, pCa, and Swallowing Rates. Jour. Clin. Dent. 1989; 1: 70-74.

36.   Stephan RM.  Intra-Oral hydrogen-Ion concentrations associated with dental caries activity. J Dent Res 23; 257-266, 1944.

37.   Vratsanos SM, Mandel ID.  Comparative plaque acidogenesis of caries-resistant vs. caries-susceptible adults. J Dent Res 61; 465-466, 1982.

38.   Scientific consensus conference on methods for assessment of the cariogenic potential of food.  JADA 1986;112:535

39.   Scientific Opinion on the substantiation of a health claim related to sugarfree chewing gum and neutralisation of plaque acids which reduces the risk of dental caries pursuant to Article 14 of Regulation (EC) No 1924/2006. EFSA Journal 8(10):1776, 2010

40.   Creanor SL, Strang R, Gimour WH, Foye RH, Brown J, Geddes DAM, Hall AF.  The effect of chewing gum use on in situ enamel lesion remineralisation.  J Dent Res 71; 1895-1900, 1992.

41.   Kashket S, Yaskell T, Lopez LR.  Prevention of sucrose-induced demineralisation of tooth enamel by chewing sorbitol gum.  J Dent Res 68; 460-462, 1989.

42.   Leach SA, Lee GTR, Edgar WM.  Remineralisation of artificial caries-like lesions in human enamel in situ by chewing sorbitol gum.  J Dent Res 68; 1064-1068, 1989.

43.   Manning RH, Edgar WM, Agalamanyi EA.  Effects of chewing gums sweetened with sorbitol or a sorbitol/xylitol mixture on the remineralisation of human enamel in situ.  Caries Res 26; 104-109, 1992.

44.   Manning RH, Edgar WM.  Salivary stimulation by chewing gum and its role in the remineralisation of caries-like lesions in human enamel in situ.  J Clin Dent 3; 71-74, 1992

45.   Steinberg LM, Odusola F, Mandel ID.  Remineralising potential, antiplaque and antigingivitis effects of xylitol and sorbitol sweetened chewing gum.  Clinical Preventive Dentistry 14; 31-34, 1992.

46.   Wefel JS, Jensen M, Hogan M, Harless J, Brechon S.  Effect of sugarless gum on human intra-oral demineralisation and remineralisation.  J Dent Res 68 (Special Issue); Abstract no 263, 1989.

47.   Edgar, W.M.  Sugar Substitutes, Chewing Gum and Dental Caries- A Review. British Dent. Jour. Vol. 184: No.1: 29-32, 1998.

48.   Dawes, C.  Salivary flow patterns and the health of hard and soft tissues.  J Amer Dent Assn.  139 (5 suppl):18S-24, 2008

49.   Stookey, GK.  The effect of saliva on dental caries.  J Am Dent Assn 139;11S-17S, 2008

50.   Scientific Opinion on the substantiation of a health claim related to sugarfree chewing gum and reduction of tooth demineralisation which reduces the risk of dental caries pursuant to Article 14 of Regulation (EC) No 1924/2006.  EFSA Journal 2010;8(10):1775.

51.   Beiswanger, B.B; Elias, A.; Mau, M.S.; Katz, B.P.; Proskin, H.M.; Stookey, G.K.  The Effects of Chewing Sugarfree Gum After Meals on Clinical Caries Incidence, J Am Dent Assn 129, 1623-1626, 1998.

52.   Alanen P, Isokangas P, Gutmann K.  Xylitol candies in caries prevention:  results of a field study in Estonian children.  Community Dent Oral Epidemiol 28:218-224, 2000

53.   Glass RL.  A two-year clinical trial of sorbitol chewing gum.  Caries Res 17:365-368, 1983

54.   Isokangas P, Alanen P, Tiekso J, Makinen KK.  Xylitol chewing gum in caries prevention:  a field study in children.  J Am Dent Assn 117:315-320., 1988

55.   Kandelman D, Gagnon G.  A 24-Month Clinical Study of the Incidence and Progression of Dental Caries in Relation to Consumption of Chewing Gum containing Xylitol In School Preventive Programs. Jour. Dent. Research 69: 1711-1775, 1990

56.   Machiulskiene V, Nyvad B, Baelum V.  Caries-preventive effect of sugar-substituted gum.  Community Dent and Oral Epidemiol. 29; 278-288, 2001.

57.   Makinen KK, Bennett CA, Hujoel PP, Isokangas PJ, Isotupa KP, Pape Jr. HR, Makinen PL.  Xylitol Chewing Gums and Caries Rates:  A 40-month Cohort Study. J Dent Res 74: 1904-1913, 1995

58.   Makinen KK, Hujoel PP, Bennett CA, Isotupa KP, Makinen PL, Allen P.  Polyol chewing gums and caries rates in primary dentition: a 24-month cohort study.  Caries Res. 30(6):408-17, 1996

59.   Makinen KK, Makinen P-L, Pape Jr. HR, Allen P, Bennet CA, Isokangas PJ, Isotupa KP.  Stabilisation of rampant caries:  Polyol gums and arrest of dentine caries in two long-term cohort studies in young subjects.  Int. Dent. J. 45:93-107, 1995

60.   Möller IJ, Poulson S.  The effect of sorbitol-containing chewing gum on the incidence of dental caries;  plaque and gingivitis in Danish schoolchildren.  Community Dent. Oral Epidemiol 1:58-67, 1973

61.   Peng B, Petersen PE, Bian Z, Tai B, Jiang H.  Can school-based oral health education and a sugarfree chewing gum program improve oral health?  Results from a two-year study in China.  Acta Odontol Scand 62:328-332, 2004

62.   Scheinin A, Makinen KK, Tammisalo E, Rekola M.  Turku sugar studies XVIII; Incidence of dental caries in relation to 1-year consumption of xylitol chewing gum.  Acta Odont Scand 33:269-278, 1975

63.   Szoke J, Banoczy J, Proskin HM.   Effect of After-Meal Sucrose-Free Gum-Chewing on Clinical Caries.  Jour. Dent. Research. 80: 1725-1729, 2001

64.   Mickenautsch S, Leal S C, Yengopal V, Bezerra A C, Cruvinel V.  Sugarfree chewing gum and dental caries – a systematic review. J Appl Oral Sci 15: 83-88, 2007

65.   Deshpande A, Jadad A.  The impact of polyol-containing chewing gums on dental caries. A systemtic review of original randomized controlled trials and observational studies. JADA 139: 1602-1614, 2008.

66.   Scientific Opinion on the substantiation of health claims related to sugarfree chewing gum and dental and oral health, including gum and tooth protection and strength (ID 1149), plaque acid neutralisation (ID 1150), maintenance of tooth mineralisation (ID 1151), reduction of oral dryness (ID 1240), and maintenance of the normal body weight (ID 1152) pursuant to Article 13(1) of Regulation (EC) No 1924/2006.  EFSA Journal 2009; 7(9):1271.

67.   World Dental Federation, Endorsement of Wrigley sugarfree gum,

68.   American Dental Association, found at http://www.ada.org/1315.aspx

69.   British Dental Health Foundation, found at http://www.dentalhealth.org/tell-me-about/topic/caring-for-teeth/sugarfree-chewing-gum

70.   Health Canada.  Summary of Health Canada's Assessment of a Health Claim about Sugarfree Chewing Gum and Dental Caries Risk Reduction,  Found at http://www.hc-sc.gc.ca/fn-an/label-etiquet/claims-reclam/assess-evalu/gum-gomme-dental-carie-dentaire-eng.php

19 February 2015