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Dental Tribune Middle East & Africa Edition

14 Dental Tribune Middle East & Africa Edition | January - February 2014oral health Saliva and Oral Health ByMichaelEdgar,Colin Dawes&DenisO’Mullaneand contributedtobyHelenWhelton Excerpt from Saliva and Oral Health - An Essential Overview for the Healthcare Professional, 2012 T he presence of saliva is vital to the main- tenance of healthy hard (teeth) and soft (mucosa) oral tissues. Severe reduction of salivary output not only results in a rapid de- terioration in oral health but also has a detrimental impact on the quality of life for the suf- ferer. The anatomy and physiology of salivary glands Patients suffering from dry mouth can experience diffi- culty with eating, swallowing, speech, the wearing of den- tures, trauma to and ulcera- tion of the oral mucosa, taste alteration, poor oral hygiene, a burning sensation of the mu- cosa, oral infections including Candida and rapidly progress- ing dental caries. The sensa- tion of dry mouth or xerosto- mia is becoming increasingly common in developed coun- tries where adults are living longer. In addition, polyphar- macy is very common among the older adult population and many commonly prescribed drugs cause a reduction in salivary flow. Xerostomia also occurs in Sjögren’s syndrome, which is not an uncommon condition. In addition to specific diseases of the salivary glands, salivary flow is usually severely im- paired following radiotherapy in the head and neck area for cancer treatment in both chil- dren and adults of all ages. Clearly oral dryness is a prob- lem which faces an increas- ingly large proportion of the population. An understanding of saliva and its role in oral health will help to promote awareness among health care workers of the problems aris- ing when the quantity or qual- ity 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 research on saliva as a diag- nostic fluid. It has been used to indicate an individual’s car- ies susceptibility; 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 is that it is easily available for non-invasive col- lection and analysis. It can be used to monitor the presence and levels of hormones, drugs, antibodies, microorganisms and ions. The following information provides an overview of the functions of saliva, the anat- omy and histology of salivary glands, the physiology of saliva formation, the constituents of saliva and the use of saliva as a diagnostic fluid, including its role in caries risk assessment. Functions of Saliva Thecomplexityofthisoralfluid is perhaps best appreciated by the consideration of its many and varied functions. The functions of saliva are largely protective; however, it also has other functions, including; Fluid/Lubricant – Coats hard and soft tissue which helps to protect against mechani- cal, thermal and chemical irritation and tooth wear. Assists smooth air flow, speech and swallowing. Ion Reservoir – Solution su- persaturated with respect to tooth mineral facilitates remineralisation of the teeth. Buffer – Helps to neutralise plaque pH after eating, thus reducing time for deminerali- sation. Cleansing – Clears food and aids swallowing. Antimicrobial actions – Specif- ic (e.g. sIgA) and non-specific (e.g. Lysozyme, Lactoferrin and Myeloperoxidase) anti- microbial mechanisms help to control the oral microflora. Agglutination – Agglutinins in saliva aggregate bacteria, resulting in accelerated clear- ance of bacterial cells. Exam- ples are mucins and parotid saliva glycoproteins. Pellicle formation – Thin (0.5 μm) protective diffusion bar- rier formed on enamel from salivary and other proteins. Digestion – The enzyme -am- ylase is the most abundant sal- ivary enzyme; it splits starchy foods into maltose, maltotriose and dextrins. Taste – Saliva acts as a solvent, thus allowing interaction of foodstuff with taste buds to fa- cilitate taste. Water balance – Under condi- tions of dehydration, salivary flow is reduced, dryness of the mouth and information from osmoreceptors are translated into decreased urine produc- tion and increased drinking. Changes in plaque pH fol- lowing sucrose ingestion and buffering capacity in the presence of saliva > Page 15

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