Reducing Caries Incidence

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The understanding of the complex etiology and pathogenesis of dental caries has advanced significantly over the past decade.1 This increased level of understanding has led to new insights and the development and implementation of new caries preventive measures, particularly among high-risk populations of children and adults.2 An important outcome of these shifting trends and insights around caries is an increased understanding of the oral health benefits of chewing sugar-free gum after eating and drinking. Research shows that chewing sugar-free gum results in a 10-12 fold increase in salivary flow rate, which enhances the ability of saliva to clear the mouth of food debris and sugars, neutralize acids, and support remineralization, all of which can help to reduce the incidence of caries.3,4

Saliva is an exocrine solution consisting of 99% water. The remaining 1% consists of a variety of electrolytes and proteins. These components combined are responsible for the various functions attributed to saliva.5 It plays a significant role in maintaining oral health, helping to build and maintain the health of soft and hard tissues; when saliva flow is reduced, oral health problems such as dental caries and oral infections can develop.

In addition to moderating microbial factors and encouraging preventive dietary behaviors, a core goal in caries prevention is promoting the natural protective mechanisms of saliva.6

The pH of dental plaque is a key factor in the balance between acid demineralization of the teeth and the remineralization of the initial caries lesion. Plaque pH falls each time acid accumulates in the plaque due to bacterial acid production following the consumption of fermentable carbohydrates – mainly sugars – in foods and drinks. Conversely, plaque pH rises when the acids are washed away or neutralized by saliva, which contains the important buffer, bicarbonate.7

When the saliva pH or the plaque pH is below a ‘critical value’ of about 5.5, the saliva or plaque becomes unsaturated with respect to tooth mineral.8 As a result, tooth enamel can begin to dissolve. However, when the pH is above this value, the saliva and plaque are supersaturated with respect to tooth mineral. The calcium and phosphate ions in saliva then start to repair any damaged mineral crystals in the enamel – the process of remineralization.9

Thus, acidic conditions contribute to bringing phosphate and hydroxyl ions below saturation levels, allowing the solid hydroxyapatite crystals of the tooth mineral to dissolve. If above saturation levels, the chemical reaction will move towards remineralisation and any damaged crystals will be repaired by the acquisition of ions from the solution.9 Stimulation of saliva flow results in an increase in the washing out of acids (and sugars), and also an increase in the amount and concentration of bicarbonate buffer and of remineralizing ions.9

About Dental Caries

Dental caries is a biofilm-mediated, diet modulated, multifactorial, non-communicable, dynamic disease resulting in net mineral loss of dental hard tissues.10 It remains one of the most common non-communicable diseases in the world. Untreated caries in permanent teeth was the most common condition evaluated for the Global Burden of Disease (GBD) 2017 study, affecting 2.3 billion adults worldwide, and more than 530 million children also suffer from dental caries of primary teeth.11 The global burden of untreated carious lesions reported in 187 countries between 1990 and 2010 makes dental caries a health problem yet to be appropriately managed.12,13

Poor oral health has an adverse effect on general wellbeing and places a significant burden on public health expenditure through the cost of curative dental treatment. While the fluoridation of water supplies and changes in lifestyle have all contributed to an overall downward trend in the prevalence of dental caries,14 global rates continue to present a major public health concern. This suggests that new preventive strategies may be required to supplement existing measures in reducing the risk of dental caries and improving oral health.

Published Research

1 Pitts NB et al. Dental caries. Nat Rev Dis Primers. 2017 May 25;3:17030.

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2 Fontana M, Zero DT. Assessing patients’ caries risk. J Am Dent Assoc. 2006;137:1231–9.

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3 Stookey GK. The effect of saliva on dental caries. J Am Dent Assoc. 2008;139(Suppl.2):11S–17S.

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4 Dawes C, Macpherson LM. Effects of nine different chewing-gums and lozenges on salivary flow rate and pH. Caries Res. 1992;26:176–82.

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5 de Almeida PD, Grégio AM, Machado MA, et al. Saliva composition and functions: a comprehensive review. J Contemp Dent Pract. 2008;9:72–80.

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6 Featherstone JD. Dental caries: a dynamic disease process. Aust Dent J. 2008;53:286–91.

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7 de Almeida PD, Grégio AM, Machado MA, et al. Saliva composition and functions: a comprehensive review. J Contemp Dent Pract. 2008;9:72–80.

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8 Hicks J, Garcia-Godoy F, Flaitz C. Biological factors in dental caries enamel structure and the caries process in the dynamic process of demineralization and remineralization (part 2). J Clin Pediatr Dent. 2004;28:119–24.

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9 Pitts NB et al. Dental caries. Nat Rev Dis Primers. 2017 May 25;3:17030.

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10 Machiulskiene V et al. Terminology of Dental Caries and Dental Caries Management: Consensus Report of a Workshop Organized by ORCA and Cariology Research Group of IADR. Caries Res. 2021; 54(1):7-14.

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11 GBD 2017 Disease and Injury Incidence and Prevalence Collaborators. Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017. Lancet. 2018 Nov 10;392(10159):1789-1858.

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12 Kassebaum NJ et al. Global burden of untreated caries: a systematic review and metaregression. J Dent Res. 2015 May;94(5):650-8.

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13 Frencken JE et al. Global epidemiology of dental caries and severe periodontitis – a comprehensive review. J Clin Periodontol. 2017 Mar;44 Suppl 18:S94-S105.

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14 Bagramian RA, Garcia-Godoy F, Volpe AR. The global increase in dental caries: a pending public health crisis. Am J Dent. 2009;22:3–8.

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