Key Topics

• • Physiology of saliva in health
• • Topical treatments for dry mouth
• • Systemic treatments for dry mouth

Learning Objectives

• • To be able to list the key constituents of saliva
• • To be able to list the main causes of dry mouth symptoms
• • To be able to identify the key aspects of dry mouth management:
  • Topical treatments
  • Systemic treatments
  • Preventative treatments

Introduction

Saliva is of fundamental importance for the maintenance of oral and general health. Essentially saliva consists of water, ions and proteins that are secreted by the salivary glands. In addition to water, saliva also includes: calcium, phosphate, bicarbonate, magnesium, zinc, mucins, enzymes and immunoglobulins. These substances play important roles in oral health and function – lubricating the oral cavity, guarding against infection, protecting teeth from dietary and plaque-related acids, and enabling tasting and food consumption.

Xerostomia is the symptom of having a dry mouth, which can be as a result of reduced or altered salivary flow. In addition, xerostomia can be subjective, when a dry mouth sensation occurs with no clinical evidence of reduced or altered flow. Saliva is produced in large quantities by the major salivary glands in response to food stimulation which aids deglutination. The minor mucous glands produce a smaller quantity of thick mucinous saliva, which coats the mucosa and provides lubrication and comfort. In xerostomia, disruption or loss of this mucous film causes a sense of dryness similar that that which occurs after drinking an acidic fizzy drink regardless of the level of oral moisture. Simple salivary substitution, therefore, does little to restore the oral comfort and this severely limits the usefulness of salivary substitutes or stimulants over simply sipping water.

The prevalence of xerostomia within the general population ranges from 10% to 46%, and appears to be more common in females than males. An objectively dry mouth, with clinical evidence of altered or reduced saliva production, can be as a result of medical treatment or a symptom of an underlying disease. Example causes of xerostomia include: physiological causes (e.g. mouth breathing, anxiety), congenital (e.g. salivary gland agenesis), medical causes (e.g. drug-associated xerostomia, chemotherapy, radiotherapy of head and neck region), or underlying diseases (e.g. diabetes mellitus, Sjögren’s syndrome, HIV, Hepatitis C).

Dry mouth can impact negatively on health and quality of life – with the consequences of a chronically dry mouth including: difficulties with eating and speaking, oral soreness, susceptibility to caries and oral candidosis.

There should be a systematic approach to the management of patients suffering with a dry mouth. The key points are shown in Table 11.1.