Since chewing gum was first patented over a century ago, research shows that sugarfree gum can alleviate the discomfort of xerostomia and help protect against decay.

In 1896, Dr William Semple, a dentist from Ohio, first patented chewing gum. Advocating its use, he recognised its potential as a dentifrice¹. Over the years there has been increasing interest in the effects on oral health of chewing sugarfree gum². A century later, both the World Dental Federation and the British Dental Association recognise the benefits of chewing sugarfree gum³.

The action of chewing increases the natural production of saliva, which plays a vital role in the maintenance of oral health. Dental studies reveal that the initial stimulated salivary flow rate while chewing sugarfree gum is 10-12 times greater than the unstimulated flow rate⁴. Sugarfree chewing gum helps to alleviate the discomfort of dry mouth (xerostomia)⁵ and to protect teeth against decay^3,6,7.

Saliva and oral health

Saliva is formed primarily from the secretions of the three paired major salivary glands, the parotid, submandibular and sublingual. Minor salivary glands are situated on the tongue, palate and buccal and labial mucosa. A number of factors influence both the composition and the flow rate of saliva, including age, sex, nutritional and emotional states. Unstimulated saliva is secreted continuously while stimulated saliva is secreted in response to masticatory or gustatory stimulation.

Saliva is crucially important for:

• Buffering the acids produced in plaque from food debris.

• Supplying calcium, phosphate, hydroxyl and fluoride to remineralise incipient lesions.

• Diluting and increasing clearance of food debris from around the teeth.

Dry mouth: effects, causes and management

Xerostomia is the subjective feeling of dryness throughout the mouth. This is usually sensed when the flow of saliva is decreased to about half of the person’s normal rate. Studies conducted on outpatients and in the general population have shown that about one in four patients complain of xerostomia¹¹.

A reduction in the amount of saliva produced can lead to a variety of clinical problems:

• An increase in dental decay, located at sites generally not susceptible to caries, for example cervical margin (neck of tooth) and incisal edges.

• Ulceration of the oral mucosa, cracking and fissuring of the tongue.

• An increased susceptibility to infection both in the mouth and in the salivary glands.

• Difficulty in chewing and swallowing.

• Speech difficulties.

• Discomfort, psychological distress and social embarrassment¹².

The incidence of dry mouth increases with age and is likely to rise as the proportion of elderly people in the UK grows¹⁰. Reduced salivary flow rate is the result of hypofunction of the salivary glands. The glands source their fluid from the circulating blood, process it and secrete it into the mouth. Secretion occurs in response to parasympathetic (automatic nervous system) stimulation. Interference of blood supply to a gland, damage to its secretory function or interruption of stimuli can lead to reduced saliva production. This may be temporary, owing to anxiety or an acute infection such as mumps.

Hypofunction is also significant as it may indicate the presence of systemic disease such as:

• Rheumatoid conditions, for example Sjorgen’s syndrome.

• Endocrine disorders, for example Diabetes mellitus.

• Neurological, for example Parkinson’s disease.

• Dysfunction of the immune system, for example AIDS.

• As a result of radiation for the treatment of oral cancer.

Some of these diseases and conditions cause progressive destruction of the glands which, in most cases, is irreversible. Others may have vascular or neural effects which are transient and reversible.

Dry mouth is most commonly associated with drugs. More than 400 drugs cause oral dryness and induce salivary gland hypofunction, including anti-depressants, antihistamines, antihypertensives, antipsychotics, antiemetics, anticholinergics, decongestants, diuretics and other blood pressure drugs¹³. Xerostomia is becoming increasingly common in developed countries where adults are living longer. Polypharmacy is very common in the older population and many of the commonly prescribed drugs cause a reduction in salivary flow. Dry mouth is a very distressing symptom which is faced by an increasingly large proportion of the population.

The role of the pharmacist

When being dispensed a drug which may cause dry mouth the patient will benefit from the pharmacist’s advice on measures to relieve this side effect. Individuals can also benefit from simple dietary advice. Eating smaller portions more frequently and fewer foodstuffs which require vigorous mastication are considered to contribute to dental caries¹⁴.

Saliva substitutes

Patients with little or no responsive salivary gland tissue will need saliva substitutes and should be referred to their doctor.

Saliva stimulation

Gustatory stimuli such as sweetness and tartness induce saliva production. A number of studies have shown that chewing gum increases salivary flow in patients with xerostomia of varying aetiology^15,16,17. The objective improvement in salivary flow was associated with subjective improvement in xerostomia. Patients have shown excellent acceptance of chewing sugarfree gum to relieve dry mouth⁵.

Sugarfree chewing gum and dental health

The British Dental Association recommends chewing sugarfree gum as part of a routine dental hygiene programme to protect teeth against decay. Both xylitol and sorbitol gums enhance the remineralisation potential of plaque after only six weeks of use¹⁸. It has been proven in long-term clinical testing with children with normal salivary flow that chewing sugarfree gum for 20 minutes after eating as well as optimal use of fluorides and meticulous oral hygiene produced a significant reduction in caries (in some cases up to 40 per cent) compared with those who did not chew^19,20,21. Sugarfree gum also increases saliva flow that can provide relief from the discomfort of dry mouth.

Key messages to discuss with your customers

An effective oral healthcare regime should include:

• Consuming fewer sugar-containing foods and drinks.

• Brushing the teeth twice a day with fluoride toothpaste.

• Having regular dental check-ups.

• Chewing sugarfree gum for 20 minutes after meals and snacks.

References

1. Cloys LA, Christen AG, Christen JA. (1992) ‘The development and history of chewing gum’ Bull Hist Dent 1992; 40:57-65

2. Edgar WM, Geddes DAM (1990) Chewing gum and dental health: A review Br Dent J 173-177

3. BDA Fact file July 1996

4. Dawes C, Macpherson LMD (1992) Effects of nine different chewing gums and lozenges on salivary flow rate and pH. Caries Res 26 :176-182

5. Bjornstrom M, Axell T, Birkhed D (1990) Comparison between saliva stimulants and saliva substitutes in patients with symptoms related to dry mouth. A multi-centre study Swed Dent J 14 :153-161

6. Mandel ID, Screenby LM, Izutsu KT, Fox PC, Ferguson MM (1989) A Symposium on the Endogenous Benefits of Saliva in Oral Health Compendium;  Supplement 13

7. Markovic N, Abelson DC, Mandel ID 1988 Sorbitol gum in xerostomics. The effect on dental plaque pH and salivary flow rates’ Gerodontology 7 (2):71-75

8. Edgar WM (1990) Saliva and dental health. Br Dent J 169 :173-177

9. Whelton H (1996) The anatomy and physiology of salivary glands. Saliva and Oral Health edited by Edgar WM, O’Mullane BDJ Publishing 1-8

10. Dawes C (1996) Factors influencing salivary flow rate and composition. Saliva and Oral Health edited by Edgar WM, O’Mullane BDJ Publishing 27-41

11. Billings RJ (1989) Studies on the prevalence of xerostomia: Preliminary results. Caries Res 23 : Abstract 124. 35th ORCA Congress

12. Screebny LM (1996) Xerostomia: diagnosis, management and clinical complications. In: Edgar WM, O’Mullane DM. Ed. Saliva and Oral Health. London: BDA 4: 43-66.

13. FDI Working Group 10 (1992) Int Dent J 42(2) Supplement 2:296

14. Theilade E, Birkhead B (1986) Diet and Dental caries. Textbook of cariolgoy edited by Thylstrop A, Fejerskov O 131-166

15. Olason H, Axell T (1991) Objective and subjective efficacy of saliva substitutes containing mucin and carboxymethylcellulose. Scand J Dent Res 99: 316-319

16. Aagaard A, Godiksen G, Teglers PT, Schindt M, Glenert U (1992) Comparison between new saliva stimulants in patients with dry mouth: a placebo-controlled double blind crossover study. J Oral Path and Med. 21: 376-380

17. Risheim H, Arnegberg P (1993) Salivary stimulation by chewing gum and lozenges in rheumatic patients with xerostomia. Scand J Dent Res. 181 : 40-43

18. Steinberg LM, Odusola F, Mandel ID (1992) Remineralising potential antiplaque and antigingivitis effects of xylitol and sorbitol sweetened chewing gum. Clin Prevent Dent 14:41-34

19. Jensen ME, Wefel JS (1989) Human plaque pH response to meals and the effects of chewing gum. Br Dent J 167(6): 204-208

20. Beiswanger B B  (1996) The anticaries effects from sugarless gum: a matter of timing? Indiana University School of Dentistry

21. Szóke J, Banoczy J, Proskin HM (1999).Effect of after-meal sugarfree gum chewing on clinical caries. J Dent Res  80(8): 1725-1729