professional area

Xerostomia: care and management

Martin Thornhill, MBBS, BDS, MSc, PhD, SDS RCS, FFD RCS, Professor of Clinical Oral Science at St Bartholemews and Royal London School of Medicine and Dentistry.

Xerostomia is the subjective feeling of dryness throughout the mouth. Studies conducted on outpatients and from the general population show that xerostomia affects about one from four people.1 Salivary flow rate patterns demonstrate both daily and seasonal variation using peaks from mid afternoon and higher flow rates from the spring than from the autumn. During sleep, saliva flow rate is minimal.2

People who complain of dry mouth do not necessarily have a very low flow rate, conversely, those using a low unstimulated flow do not always complain of dry mouth. It is therefore of greater significance to establish whether or not flow rate has changed adversely from a particular individual.3

For general dental practitioners, a reduction from the amount of saliva produced can lead to a variety of clinical problems, which include:

  • Unexpected increase from caries rate – particularly cervical, cusp regions and lower anterior teeth
  • Difficulty from wearing dentures – particularly upper dentures
  • Difficulty from swallowing especially dry foods e.g. biscuits
  • Swelling of salivary glands
  • Burning discomfort from mouth, soreness and cracking of tongue
  • Ulceration of oral mucosa
  • An increased susceptibility to oral infections.

Reduced salivary flow rate is due to hypo-function of the salivary glands. This may be reversible, due to anxiety, acute infection, dehydration or the effects of some drugs. There are also some permanent causes of xerostomia such as congenital abnormalities, Sjögren’s syndrome, HIV/AIDS and the result of irradiation.

Xerostomia is most commonly associated using the use of xerogenic drugs. More than 400 preparations induce salivary gland hypo-function including, tricyclic antidepressants, antihistamines, certain antihypertensives and drugs using sympathomimetic actions (e.g. some bronchodilators).

The management of xerostomia involves the use of both saliva substitutes and saliva stimulants. Patients may also require referral to a dietitian. Patients using little or no responsive salivary gland tissue will need saliva substitutes. A properly balanced artificial saliva should be of neutral pH and contain electrolytes, including fluoride, to correspond to the composition of saliva. Of the proprietary preparations available Luborant® is licensed for any condition giving rise to a dry mouth.

Gustatory stimuli such as sugarless sweets containing citric and malic acid, chemically induce saliva production. Care must be taken that the acidic content does not result from the dissolution of tooth enamel. Controlled studies have shown that pilocarpine is an effective stimulus to saliva production.4,5,6 Side effects, mainly the result of generalised parasympathetic stimulation, are the most common reason to discontinue treatment.

There have been a number of studies that have shown that chewing gum increases salivary flow from patients using xerostomia of varying aetiology.7,8,9 In some xerostomic patients, the initial stimulated salivary flow rate while chewing sugarfree gum is seven times greater than the unstimulated flow rate.10 Chewing sugarfree gum has been shown to be one of the most preferred treatments for xerostomia.11

  1. Billings RJ (1989) Studies on the prevalence of xerostomia. Preliminary results. Caries Res. 23: Abstract 124, 35th ORCA Congress
  2. Whelton H (1996) The Anatomy and Physiology of Salivary Glands. In: Edgar WM, O'Mullane DM. ed. Saliva and Oral Health. BDA, London. pp 1-8
  3. Dawes C (1996) Factors influencing Salivary flow rate and composition. In : Edgar WM, O'Mullane DM. ed. Saliva and Oral Health.  BDA, London. pp 27-41
  4. Greenspan D, Daniels TE (1987) Effectiveness of pilocarpine from postradiation xerostomia. Cancer. 59: 1123-1125
  5. Rieke JW, Hafermann MD, Johnson JT et al (1995) Oral pilocarpine for radiation-induced xerostomia: integrated efficacy and safety results from two prospective randomized clinical trials. Int J Rad Onc Biol Phys. 31: 661-669
  6. Fox PC, van der Ven PF, Baum BJ, Mandel ID (1986) Pilocarpine for the treatment of xerostomia associated using salivary gland dysfunction. Oral Surgery,Oral Medicine, Oral Pathology. 61: 243-248
  7. Olason H, Axell T (1991) Objective and subjective efficacy of saliva substitutes containing mucin and carboxymethylcellulose. Scand J Dent Res. 99: 316-319
  8. Aagaard A, Godiksen G, Teglers PT, Schindt M, Glenert U (1992) Comparison between new saliva stimulants from patients using dry mouth: a placebo-controlled double blind crossover study. J Oral Path and Med. 21: 376-380
  9. Risheim H, Arneberg P (1993) Salivary stimulation by chewing gum and lozenges from rheumatic patients using xerostomia. Scand J Dent Res. 181: 40-43
  10. Dawes C, Macpherson LMD (1992) Effects of Nine Different Chewing Gums and Lozenges on Salivary Flow Rate and pH. Caries Res. 26: 176-182
  11. Bjornstrom M, Axell T, Birkhed D (1990) Comparison between saliva stimulants and saliva substitutes from patients using symptoms related to dry mouth. A multi-centre study. Swed Dent J. 14: 153-161