Please activate JavaScript!
Please install Adobe Flash Player, click here for download

Dental Tribune Middle East & Africa Edition

32 Dental Tribune Middle East & Africa Edition | November-December 2014oral health > Page 33 Saliva and Oral Health By Michael Edgar, Colin Dawes & Denis O’Mullane and contributed to by Mahvash Navazesh Excerpt from Saliva and Oral Health-An Essential Overview for the Healthcare Professional E xcerpt from Saliva and Oral Health-An Essential Overview for the Health- care Professional, 2012, by Mi- chael Edgar, Colin Dawes & Denis O’Mullane and contrib- uted to by Mahvash Navazesh. The presence of saliva is vital to the maintenance of healthy hard (teeth) and soft (mucosa) oral tissues. Severe reduction of salivary output not only results in a rapid deterioration of oral health but also has a detrimental impact on the quality of life for the sufferer. An understanding of saliva and its role in oral health helps to promote awareness among oral health care professionals of the problems arising when the quantity or quality of saliva is decreased; this awareness and understanding is important to the prevention, early diagnosis and treatment of the condition. There is an extensive body of re- search on saliva as a diagnostic fluid. It has been used to indicate an individual’s susceptibility to developing caries; it has also been used to reflect systemic physiological and pathological changes which are mirrored in saliva. One of the major ben- efits of saliva as a diagnostic fluid is that it is easily available for non-invasive collection and analysis. It can be used to moni- tor the presence and levels of hormones, drugs, antibodies, microorganisms and ions. The following article provides an overview of oral complica- tions associated with salivary gland hypofunction, and aetiol- ogy, diagnosis, clinical implica- tions and management of xeros- tomia. Xerostomia and Salivary Gland Hypofunction Saliva plays a significant role in the maintenance of oral-phar- yngeal health. Subjective com- plaints of a dry mouth (xerosto- mia) and objective evidence of diminished salivary output (sali- vary gland hypofunction) are common conditions, particu- larly in medically compromised older adults. They can result in impaired food and beverage in- take, a sundry of oral disorders, and diminished host defence and communication. Persistent salivary gland hypofunction can produce permanent oral and pharyngeal disorders and im- pair a person’s quality of life.1, 2 Global estimates of xerostomia and salivary gland hypofunc- tion are difficult to ascertain due to varying study design, dif- ferences in study populations, usage of the terms xerostomia and salivary gland hypofunction interchangeably, utilisation of different diagnostic criteria and saliva collection methods, and small sample sizes. However, overall, the preva- lence of xerostomia and salivary gland hypofunction increases with age and affects approxi- mately >30% of the population aged 65 years and older. There are multiple causes of xerostomia and salivary gland hypofunction, the most common being drug-induced, since most older adults are taking at least one medication that causes sali- vary gland hypofunction. It is dif- ficult, however, to estimate the true prevalence of xerostomia in older adults taking medications. The prevalence of xerostomia is nearly 100% among patients with Sjögren’s syndrome, an autoimmune exocrinopathy af- fecting between 1-4% of older adults. Estimates of the prevalence of xerostomia in adult ambulatory and nursing home populations range from 16-72%.3 Combin- ing the prevalence of xerosto- mia associated conditions with the percentage of adults with these conditions who complain of xerostomia yields the above- mentioned general estimate of approximately 30% xerostomia prevalence among adults 65 years and older. Approximately 80% of all per- sons over age 65 have at least one chronic condition and 50% have at least two. Hypertension and heart diseases, diabetes, ar- thritis and cancer are the most frequently occurring conditions among older adults. These con- ditions, and the medications of- ten prescribed for their manage- ment, could impact the structure and function of salivary glands leading to complaints of xerosto- mia or clinical evidence of sali- vary gland hypofunction. Diagnosis of xerostomia and salivary gland hypofunction Subjective responses and questionnaires The establishment of a diagnosis of xerostomia may be initiated with patients’ complaints and can be advanced with the use of questionnaires. It should be noted that a patient’s presenting complaint may not be dry mouth in spite of the presence of sali- vary gland hypofunction. There- fore, lack of complaint should not be perceived as presence of adequate saliva secretion. Many of the common oral symptoms of dry mouth are associated with mealtime: altered taste, diffi- culty eating, chewing, and swal- lowing, particularly dry foods, and especially without drinking accompanying liquids. Patients complain of impaired denture retention, halitosis, stomato- dynia, and intolerance to acidic and spicy foods.4 Night-time xe- rostomia is also common, since salivary output normally reach- es its lowest circadian level dur- ing sleep and may be exacerbat- ed by mouth breathing.5 General oral examination Extraoral findings associated with salivary gland hypofunction may include dry and cracked lips that are frequently colonised with Candida species (angular cheilitis). Visible and palpable enlarged major salivary glands occur secondary to salivary in- fections and obstructions (e.g. bacterial parotitis, mumps, and Sjögren’s syndrome). A swollen parotid gland can displace the earlobe and extend inferiorly over the angle of the mandible, whereas an enlarged subman- dibular gland is palpated medial to the posterior-inferior border of the mandible. There are numerous intraoral complications associated with salivary gland hypofunction. Oral mucosal surfaces become desiccated and easily friable. The tongue can lose its filiform papillae and will appear dry, erythemic, and raw with an ir- ritated dorsal surface. Mucosal tissues are susceptible to de- veloping microbial infections, the most common being can- didiasis. This intraoral fungal infection manifests itself as ery- thematous candidiasis beneath prostheses and as pseudomem- branous candidiasis, which pro- duces a white plaque that can be removed from mucosal surfac- es. Clinicians can also observe a decrease or an absence of saliva pooling in the anterior floor of the mouth. A second frequent problem is dental caries that occurs both on coronal and root surfaces. New caries lesions can develop on surfaces not normally affected (e.g. incisal edges of anterior teeth), and recurrent lesions are prevalent on the margins of ex- isting restorations. Edentulous and partially dentate adults us- ing removable prostheses have diminished denture retention, which will adversely impact chewing, swallowing, speech, and nutritional intake. Denture- bearing tissues can develop ery- thematous candidiasis and trau- matic and painful lesions due to tissue trauma. Saliva Collection Numerous investigators have attempted to define the lower limits of ‘normal’ salivary flow rates. However, there is substan- tial variability in flow rates that makes it difficult to define diag- nostically useful ranges of glan- dular fluid production. In stud- ies of healthy persons across the lifespan, unstimulated fluid se- cretion varies 10-100 fold, while stimulated secretion varies 10- 20 fold.6, 7 In patients considered to be at risk for developing salivary gland hypofunction, it would be useful to monitor salivary flow rates over time. Most investi- gators consider a diagnosis of salivary gland hypofunction if the unstimulated whole salivary flow rate is less than 0.1 ml/min using standardised techniques. Unstimulated secretions are probably more indicative of sali- vary gland hypofunction com- pared with stimulated secre- tions, since saliva is produced under unstimulated conditions during most of the hours a per- son is awake. The most com- mon collection technique for unstimulated whole saliva is to have a patient refrain from eating, drinking, smoking, or performing oral hygiene for at least 60 minutes prior to saliva collection. The patient is seated in a quiet environment with the head tilted forward. Immedi- ately before the test begins the patient should swallow any re- sidual saliva that may be in the mouth. The time is recorded and the person is instructed to allow saliva to flow gently into a pre- weighed test tube or other con- tainer placed under the chin for five minutes without swallow- ing or spitting. At five minutes the person is instructed to ex- pectorate the remaining saliva into the container. The volume is recorded gravimetrically and expressed as ml/min. Stimulated whole salivary flow rates of less than 0.5 ml/min are also considered to be suggestive of salivary hypofunction. The most common technique for collecting this form of saliva is with the use of a standard piece of paraffin wax or unflavoured gum base (typically 1-2 g). A test tube or similar container with the paraffin or gum base is weighed prior to saliva col- lection. The person is instructed to swallow any residual saliva that may be in the mouth before the saliva collection begins. A timer begins and the person is instructed to chew the wax or gum base at a rate of 60 chews/ minute. Without swallowing, the patient expectorates all saliva into the pre-weighed container placed under the chin at each 60 second interval. At five minutes the person is instructed to ex- pectorate the remaining saliva and wax into the container and the collection is completed. The volume is recorded gravimetri- cally, and expressed as ml/min. Values below 45% of normal lev- els can be used to define salivary gland hypofunction. It is also generally accepted that when glandular fluid production is de- creased by about 50%, patients will begin to experience xerosto- mia.8 The best strategy is simply to monitor a patient’s salivary health (both objectively and sub- jectively) over time to determine whether there are demonstrable changes.9 Clinical implications of xeros- tomia and salivary gland hy- pofunction Dental caries and dental ero- sion One of the most common oral conditions that develop as a re- sult of salivary gland hypofunc- tion is new and recurrent dental caries. In the presence of persis- tent salivary gland hypofunction, the inability of the salivary sys- tem to restore oral pH towards neutrality and inhibit certain bacteria after food and bever- age ingestion leads to an oral environment conducive to mi- crobial colonisation with caries- associated microorganisms and enamel demineralisation. The margins of existing restorations are also vulnerable to recurrent decay. Salivary hypofunction- associated root surface caries is a particularly difficult condition to diagnose and treat and, there- fore, identification of patients at risk will allow measures to be taken to preserve the dentition. With deficient remineralisa- tion, dental erosion is a more frequent occurrence in patients with salivary gland hypofunc- tion. The cervical regions of teeth occasionally receive great- er abrasion from tooth brushes and are susceptible to dental erosion. Occlusal and incisal surfaces exposed to attritional and traumatic forces can also undergo greater loss of enamel and dentine when there is insuf- ficient saliva to permit reminer- alisation. Gingivitis The increase in salivary output during and immediately after the consumption of foods and fluids assists in the lavage of the oral cavity and the removal of food particles from oral surfaces. Conversely, salivary gland hypo- function is frequently associated with retained food particles, particularly in interproximal re- gions and beneath denture sur- faces, and can cause gingivitis. Long-standing gingivitis may develop into periodontal loss of attachment, so patients with chronic hyposalivation are at risk for developing gingival and periodontal problems. Interestingly, most studies have not demonstrated significantly greater levels of periodontal dis- ease in patients with Sjögren’s syndrome compared with healthy controls,10 which may be due to greater attention to oral health and more frequent use of professional dental services. In addition, while several studies have demonstrated significant- ly greater numbers of caries- associated mutans streptococci and lactobacilli in patients with salivary gland hypofunction compared with healthy controls, similar levels of micro-organ- isms associated with gingival inflammation were detected in both populations.11 Therefore, the primary dental problem in patients with salivary gland hy- pofunction is dental caries, with less risk (but greater than that for healthy individuals) for de- veloping gingival and periodon- tal problems. Impaired quality of life Many of the oral-pharyngeal sequelae of salivary gland hy- pofunction and chronic xeros- tomia lead to an impaired qual- ity of life. Dentoalveolar and oropharyngeal infections can rapidly lead to systemic disease, particularly in medically com- plex patients. Desiccated and friable oral mucosal tissues are more likely to develop traumatic lesions, especially in denture- wearing older adults, which cause pain and interfere with nutritional intake. Also, dysgeu- sia (taste function), dysphagia CAUSES OF XEROSTOMIA AND SALIVARY GLAND HYPOFUNCTION: • MEDICATIONS • ORAL DISEASES • SYSTEMIC DISEASES • HEAD AND NECK RADIOTHERAPY

Pages Overview