ReviewSalivary hypofunction: An update on aetiology, diagnosis and therapeutics
Introduction
Saliva is of paramount importance for the maintenance of oral and general homeostasis. It displays a crucial role in the digestive function, taste, cleaning, hydratation of the oral mucosa, and protection of the teeth, due to buffering and remineralization properties. Besides, saliva controls the composition of the oral microflora due to antibacterial, antifungal and antiviral properties, protecting the body from deleterious extrinsic influences. Saliva is composed of more than 99% water along with electrolytes; the protein components include immunoglobulins, digestive enzymes such as amylase and lipase, and antibacterial and antifungal enzymes, as well as mucins.1, 2, 3, 4 Salivary secretion is controlled by the autonomous nervous system, mainly by parasympathetic nerve signals. About 90% of saliva is produced by the major salivary glands and the daily volume varies from 0.5 to 1.0 L.4, 5, 6 When at rest, 65% of saliva is produced by the submandibular glands, which produce saliva rich in mucin, which supplies lubrification for the mucosa. Under stimulation, the parotids account for 50% of salivary volume.4, 5, 7
Nederfors8 suggests that salivary dysfunctions can be divided into three aspects: xerostomia, as subjective alteration; hyposalivation, as objective reduction of salivary flow and alterations in salivary composition. In early stages, hyposalivation is characterized by decreased salivary volume, besides saliva is thick and dispersed. The oral mucosa becomes dry and atrophic, and the patients can gradually show dysgeusia, dysphagia and dysarthria, as well as risk of developing ulcerations, caries, gingivitis, periodontitis, candidosis, and bacterial sialadenitis, among others.9, 10 Those changes cause important harm to the oral homeostasis and to the quality of life.
Considering the abovementioned, the present study is an updated approach of the main risk factors associated to salivary dysfunctions, such as drugs, systemic diseases, radiation and ageing. The diagnostic methods and therapeutic measures, including regenerative therapies and the use of stem cells to restore salivary function are also discussed. A Medline/PubMed/search was conducted using the terms xerostomia, hyposalivation, dry mouth and salivary hypofunction in combination with aetiology, drugs, systemic disorders, diagnosis, management, and treatment. Articles published in the English language were selected and reviewed. Suitable references from these articles were also reviewed.
Section snippets
Diagnosis of salivary dysfunctions
The diagnosis of salivary dysfunctions can be obtained by means of subjective and objective methods. These methods can be classified into questionnaires or interviews, secretion tests, mucosal surface tests, qualitative analyses, functional analyses and glandular morphology analyses11 (Table 1).
Subjective methods are used to determine the intensity and cause of xerostomia.12 A number of questionnaires have been utilized, and there is not a consensus on the best form of grading xerostomia,
Drugs
Several drugs are able of inducing hyposalivation and xerostomia, but they rarely cause irreversible damage to the salivary glands. In Table 2 were listed classes of drugs with potential to cause salivary dysfunction. Unfortunately few studies have examined salivary flow, much of the data, being based on a subjective complaint of dry mouth. Besides, little data about the effects of many supposed xerostomia-inducing drugs on salivation are available. Although the exact mechanisms whereby some
Therapeutic options
The therapeutic approach of salivary dysfunctions depends basically on residual glandular function and is aimed at the alleviation of symptoms and prevention and correction of eventual sequelae, as well as at the treatment of associated systemic diseases. The treatment of hyposalivation and xerostomia can be classified as (1) preventive, (2) symptomatic, (3) topical and systemic stimulants, (4) disease-modifying agents, and (5) regenerative.81, 150
Conclusions
Salivary dysfunctions are common, have a negative impact on the quality of life, and can be caused by a number of local and systemic conditions. In the present study we described subjective methods, as well as objective methods for determining alterations in salivary secretion. In addition to this, we addressed the possible etiologic factors and established treatments in the literature, as well as new therapeutic strategies still under investigation. Clinicians must be aware of the signs and
Funding
There is no funding source to state in this research.
Competing interest
There is no conflict of interest in this research.
Ethical approval
Not applicable.
References (200)
- et al.
Health benefits of saliva: a review
J Dent
(2005) - et al.
Xerostomia: a day and night difference
Radiother Oncol
(2012) - et al.
Clinical assessment of oral dryness: development of a scoring system related to salivary flow and mucosal wetness
Oral Surg Oral Med Oral Pathol Oral Radiol
(2012) - et al.
Development of a Visual Analogue Scale questionnaire for subjective assessment of salivary dysfunction
Oral Surg Oral Med Oral Pathol Oral Radiol Endod
(2001) - et al.
Lip biopsy for the diagnosis of Sjögren's syndrome: beware of the punch
Int J Oral Maxillofac Surg
(2014) - et al.
Imaging the major salivary glands
Br J Oral Maxillofac Surg
(2011) - et al.
Modified schirmer test – a screening tool for xerostomia among subjects on antidepressants
Arch Oral Biol
(2014) - et al.
The spirometric efficacy of once-daily dosing with tiotropium in stable COPD: a 13-week multicenter trial
Chest
(2000) - et al.
Activation of alpha(2)-adrenoceptors in the lateral hypothalamus reduces pilocarpine-induced salivation in rats
Neurosci Lett
(2009) - et al.
Calcium antagonists cause dry mouth by inhibiting resting saliva secretion
Life Sci
(2007)
Adjuvant chemotherapy in breast cancer patients induces temporary salivary gland hypofunction
Oral Oncol
A 4-year longitudinal evaluation of xerostomia and salivary gland hypofunction in the Women's Interagency HIV Study participants
Oral Surg Oral Med Oral Pathol Oral Radiol Endod
Tramadol-induced oral dryness and pilocarpine treatment: effects on total protein and IgA
Arch Oral Biol
Side effects of antidepressants during long-term use in a naturalistic setting
Eur Neuropsychopharmacol
International trial of long-term dexfenfluramine in obesity
Lancet
The management of Sjögren's syndrome in dental practice
J Am Dent Assoc
Whole saliva in systemic lupus erythematosus patients
Oral Surg Oral Med Oral Pathol
Qualitative and quantitative changes in saliva among patients with thyroid dysfunction prior to and following the treatment of the dysfunction
Oral Surg Oral Med Oral Pathol Oral Radiol
Biochemical composition of human saliva in relation to other mucosal fluids
Crit Rev Oral Biol Med
Saliva – the defender of the oral cavity
Oral Dis
Signs of oral dryness in relation to salivary flow rate, pH, buffering capacity and dry mouth complaints
BMC Oral Health
Salivary secretion, taste and hyposalivation
J Oral Rehabil
The oral mucosa as a therapeutic target for xerostomia
Oral Dis
Xerostomia and hyposalivation
Adv Dent Res
Oral medicine – update for the dental practitioner: dry mouth and disorders of salivation
Br Dent J
Xerostomia: prevalence, assessment, differential diagnosis and implications for quality of life
Oral Dis
A systematic review of methods to diagnose oral dryness and salivary gland function
BMC Oral Health
Impact of dry mouth conditions on oral health-related quality of life in older people
Gerodontology
The influence of xerostomia after radiotherapy on quality of life: results of a questionnaire in head and neck cancer
Support Care Cancer
Novel aspects of Sjögren's syndrome in 2012
BMC Med
A simple test for salivary gland hypofunction using Oral Schirmer's test
J Oral Pathol Med
Tear and saliva ferning tests in Sjögren's syndrome (SS)
Clin Rheumatol
Non-invasive objective evaluation of radiotherapy-induced dry mouth
J Oral Pathol Med
Sialochemistry in Sjögren's syndrome: a review
J Oral Pathol Med
Sialometry and sialochemistry: diagnostic tools for Sjögren's syndrome
Ann Rheum Dis
Lactoferrin, amylase and mucin MUC5B and their relation to the oral microflora in hyposalivation of different origins
Oral Microbiol Immunol
Salivary gland imaging
J Calif Dent Assoc
Semi-quantitative evaluation of salivary gland function in Sjögren's syndrome using salivary gland scintigraphy
Clin Rheumatol
Quantitative salivary gland scintigraphy
J Nucl Med Technol
The wafer test: a semi-quantitative test to screen for xerostomia
Rheumatology
Salivary gland function evaluated by diffusion-weighted MR imaging with gustatory stimulation: preliminary results
J Magn Reson Imaging
Ultrasound in sialadenitis
J Ultrasound
Diagnosis and treatment of xerostomia (dry mouth)
Odontology
A reference guide to drugs and dry mouth – 2nd edition
Gerodontology
Adverse reactions to antidepressants
Br J Psychiatry
Effects of antidepressants and benzodiazepines on stimulated salivary flow rate and biochemistry composition of the saliva
Oral Surg Oral Med Oral Pathol Oral Radiol Endod
Olanzapine vs haloperidol in geriatric schizophrenia: analysis of data from a double-blind controlled trial
Int J Geriatr Psychiatry
Fluphenazine versus low-potency first-generation antipsychotic drugs for schizophrenia
Cochrane Database Syst Rev
Salivary production in Parkinson's disease
Mov Disord
Saliva secretion in patients with allergic rhinitis
Int Arch Allergy Immunol
Cited by (154)
Evaluation of photobiomodulation in the salivary production of patients with hyposalivation induced by antihypertensive drugs – A blind, randomized, controlled clinical trial
2024, Complementary Therapies in Clinical PracticeThe potential association between salivary gland hypofunction and systemic homeostasis
2024, Medical HypothesesSialagogic Effects Through Olfactory Stimulation with Mastic Resin and α-pinene Volatiles in vivo
2023, Biomedicine and Pharmacotherapy