Areas of new knowledge

Formation of saliva
  • Saliva is produced by 3 major glands, parotid, submandibular and sublingual glands.
  • The viscosity of the saliva produced depends on the cells it derives from, i.e. serous, mucus cells.
  • The production of saliva is innervated by the autonomic nervous control
  • While neurotransmitters affect the quantity of saliva produced.
Composition of saliva
  • Organic composition
--proteins (major content of organic composition of saliva; about 20 different proteins have been identified in human saliva.)
--free amino acids

Proteins present in the saliva serve several important functions in saliva.

  • Inorganic composition
--hydrogen ions
--inorganic phosphate
Inorganic compositions of saliva affect the pH and buffering capacity of saliva.
  • Variation in saliva composition
Salivary composition, both organic and inorganic, changes in unstimulated and stimulated saliva. Several factors have been identified to contribute to this variation, with more under further investigations.

Function of saliva
  • protection of the teeth through mechanisms that relate to its chemical composition (water, ions, gases, buffers, and salivary proteins) and mechanical effects of saliva flow
---digestive function

---inhibition of dental caries
---buffering acid produced by oral microbes
---anti-microbial function
---formation of the dental pellicle
---mechanical cleansing of the oral cavity

  • quantity and quality of saliva vary with situational changes, mediated by the parasympathetic and sympathetic pathways

Saliva hypofunction
  • Salivary gland hypofunction does not only affect your oral health, but are also related to other systemic diseases. It is important to know the main causes of salivary gland hypofunction in order to prevent it.
Saliva hypofunction management and therapies
  • Preventive Therapy: Precautionary measures to prevent the onset of dental caries and other oral infections due to salivary gland hypofunction.
  • Symptomatic Therapy: Methods that relieve the symptoms of salivary gland hypofunction without treating the cause of hypofunction.
  • Local and Topical Therapies: Methods of relieving salivary gland hypofunction by addressing a localised area.
  • Systemic Therapies: Treatment of the cause of salivary hypofunction by increasing the salivary output of dysfunctional salivary glands. However, this treatment can also affect other regions of the body, leading to undesirable side effects.
  • Therapies directed at an underlying systemic cause: Treatment of the diseases e.g. HIV, cancer that had reduced the salivary output of salivary glands.
  • Therapies that require further studies

Areas or concepts which were difficult to understand

Formation of saliva
  • The anatomy, structure and histology of salivary glands which are interlinked to give rise to the composition of saliva.
  • The different types of cells (mucus/serous) that are involved in the type of saliva produced, and how each salivary gland can be made up of either one or both types of cells.
  • Formation of saliva through the innervation by nerves as well as the physiological process that affects the final composition of saliva.
Composition of saliva
  • How do composition of saliva changes accordingly with respect to different natures of stimulation (eg. acidic stimulation, carbohydrate-rich food intake) and degrees of stimulation (eg. time and intensity of stimulation)

Function of saliva

Saliva hypofunction

Difference between Xerostomia and Salivary gland hypofunction. The former is a symptom of the latter, rather than a disease on its own

Saliva hypofunction management and therapies

  • Side effects of pilocarpine and cevimeline due to the physiology of their actions.
  • Classification of therapies -- some local/topical therapies can also be applied to symptomatic and preventive therapies.
  • The choice of drugs and therapies for different causes of xerostomia.

Areas of controversy Areas for further research

Composition of saliva
  • several factors, eg. phosphate in diet, which have been suggested to affect salivary composition in stimulated saliva are still under investigation.
  • Numerous studies and experiements have been done to investigate the concentration of each individual organic compound, especially proteins, of human saliva. However, controversies are common for certain protein concentrations like for lactoferrin and lysozyme. Separate investigations carried out by different scientists often provide results with considerable discrepancy, making it difficult to conclude about certain actual protein concentrations.

Function of saliva

Saliva hypofunction
  • Salivary gland hypofunction as a natural part of ageing.
  • How severe must the loss of acinar be to cause Xerostomia. (Ageing involves loss in acinar tissues as well, but not necessarily xerostomia)
Saliva hypofunction management and therapies
  • Numerous kinds of therapies such as acupuncture and certain drugs are still in clinical trials with conflicting results. It will require further studies for verification of their benefits.
Areas which were fascinating and stirred your desire to learn more

Formation of saliva
  • The simple process of saliva formation is actually much more complex than just salivation.
  • There are numerous glands and processes that affect not only the production but also the consistency and composition of saliva.
  • The different glands with different cells that correlate to the production of saliva.

Composition of saliva
  • Saliva contains numerous components, both organic and inorganic, of which the concentration vary with different nature and degree of stimulations.
  • Composition of saliva is essential not only to healthy oral environment but also to general well-being.

Function of saliva

Saliva hypofunction
  • The numerous roles that saliva has in our lives. (long list of signs and symptoms)

Saliva hypofunction management and therapies
  • The wide variety of therapies available to treat and relieve the symptoms of salivary hypofunction depending on the severity and causes of hypofunction.
  • An area with vast potential for ground breaking research.

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