The impact of sugarfree gum on oral health.

This article was previously published in a supplement for Dentistry magazine in the UK.

Catherine Stillman-Lowe explores the evidence behind the claim that chewing sugarfree gum, with its saliva inducing effect, is a beneficial tool in the battle against caries, dental erosion and xerostomia.

Chewing sugarfree gum can be seen as a useful adjunct to the individual self-care and public health measures recommended by The Scientific Basis of Oral Health Education.

This article sets out the benefits of sugarfree gum for patients in this context and the role of the product in preventing and managing dental caries, erosion and xerostomia.

The benefits of sugarfree gum for dental caries

As Edgar has stated (1999), the oral health impact of chewing gum has been considered for many years, both from positive and negative perspectives.

Until sugarfree products became available, the main concern was the contribution of sugar from gum to the dietary caries challenge. However, sugarfree gum has been found to be non-cariogenic and even anti-cariogenic. The anti-caries effects are attributable to increased salivary flow during gum chewing due to the gustatory and masticatory stimuli, and the consequent enhancement of its protective actions. The effect of stimulation is to increase the concentration of bicarbonate in the saliva entering the mouth. This raises the pH of the saliva and greatly increases its buffering power. It is therefore much more effective in neutralising and buffering food acids and acids arising in plaque.

At the same time, there are effects on the phosphate and calcium in saliva. These changes in the composition of stimulated saliva lead to a greater ability to prevent a fall in pH, and a greater tendency to favour hydroxyapatite crystal growth. The greater volume and rate of flow of stimulated saliva results in an increased ability to clear sugars and acids from around the teeth (for more information, see Edgar’s article A review of the positive effects of chewing sugar free gum on oral health at www.betteroralhealth.info).

Rugg-Gunn and Nunn (1999) have stated that the results of clinical trials of sugarfree gum show that chewing actually helps to prevent caries - probably by encouraging healing of very early carious lesions through increased salivary flow. They add that there is a dose-response relationship, since the caries-preventative effect increases as the frequency of chewing gum per day increases.

Dental erosion and sugarfree gum

Dental erosion, which causes wearing away of the surface of the teeth, appears to be an increasing problem.

The cause is usually acid in the soft drinks and juices increasingly being consumed by children and young adults, 50% of whom are now affected to some degree.

Erosion can also be caused by gastric regurgitation, as can occur in pregnancy, or due to conditions such as hiatus hernia or bulimia (Levine RS & Stillman-Lowe CR, 2004).

Shaw and O’Sullivan (2000) have suggested that dietary counselling for the management of erosion in children should emphasise the limitation of acidic foods and drinks to mealtimes (which is the time of maximum salivary flow and increased buffering capacity), and their avoidance last thing at night, as the salivary flow rate is negligible at night during sleep.

In addition, there is some scientific evidence that the use of sugarfree gum, like ORBIT, is helpful in increasing salivary flow and encouraging tooth remineralisation. Finishing a meal with something to neutralise any acids, such as a little cheese or milk, is also useful.

Xerostomia

Xerostomia is the subjective complaint of dry mouth, usually related to reduced salivary flow. It is a distressing problem associated with a range of local and systemic factors, and may be temporary or permanent.

In dentate patients, xerostomia can predispose to rapidly progressive caries, erosion and periodontal disease; in the edentate, candida infection is a frequent problem. In an ageing population, the condition is likely to become more common because of an increased dependency on medication by individuals and demographic changes (Levine RS, 2001). The principles of management include

Elimination of aetiological factors, such as drugs taken by the patient
Promoting salivary stimulation - sugarfree gum is effective and convenient. For those patients with teeth of their own, it is clearly a better option than sugar-containing boiled sweets
Use of saliva substitutes, though these may be of limited value – frequent sipping of iced water may be more helpful.

Discussing the mouth care of patients receiving palliative care, Pemberton and Thornhill (1998) confirm that the stimulation of residual salivary function is an important part of the management of dry mouth. Patients often prefer salivary stimulation to substitution, with sugarfree chewing gum being both effective and widely available.

Lastly, Rugg-Gunn and Nunn (1999), in their discussion of dietary advice for elderly people, note that disuse atrophy affects the saliva glands as it does other tissues.

While disease can cause atrophy, chewing can increase the size of the salivary glands and increase salivary flow.

Recommending foods that require chewing is likely to improve oral health, therefore, not only by causing a strong flow of saliva while food is chewed but also by improving the ability of glands to respond to future stimuli. This provides an important reason for recommending chewing sugarfree gum.

Advice to patients

From a theoretical aspect, sugarfree chewing gum like Orbit may have a positive benefit for dental health by increasing salivary flow during chewing, which helps to neutralise plaque acid activity

The majority of clinical studies have indeed found a positive benefit, and the use of sugarfree gum can be recommended in addition to the self-care measures of reducing the frequency and amount of consumption of foods and drinks containing sugars, and brushing thoroughly twice a day with a fluoride toothpaste.

Specifically:

Patients can be advised that chewing sugarfree gum immediately after meals or snacks in particular, can help to prevent dental caries
Patients with xerostomia, or dental erosion caused by their dietary habits, can be advised that chewing sugarfree gum may benefit their conditions, and is an option worth considering as part of the overall management of their case.

This dietary advice fulfils the criteria of being positive and practical - as well as palatable (for those patients who enjoy chewing gum).

Looking at measures in the wider community as opposed to the dental surgery, in Scotland it has been suggested that sugarfree gum can have a role to play in the promotion of good oral health in the workplace, alongside a range of other steps to encourage healthy eating (visit the NHS Health Scotland website at www.hebs.com/safeandhealthyworking for further information on this concept).

References

Edgar W M (1999) A role for sugar-free gum. Journal of Clinical Dentistry 10: 89-93.

Edgar M. A review of the positive effects of chewing sugarfree gum on oral health. Article available at www.betteroralhealth.info

Levine RS (2001) Xerostomia - a problem in an ageing population. BDA News 14(5): 30-31

Levine RS and Stillman-Lowe CR (2004) The Scientific Basis of Oral Health Education. London, BDJ Books.

Macquire A and Rugg-Gunn A J (2003) Xylitol and caries prevention - is it a magic bullet? British Dental Journal 194: 429-436

Pemberton M and Thornhill MH (1998) Simple antiseptic mouthwashes are best for infection (letter). British Medical Journal 316: 1246

Shaw L and O’Sullivan E (2000) Diagnosis and prevention of dental erosion in children. International Journal of Paediatric Dentistry 10: 356-365