Importance of Saliva

The assessment of saliva in the dental patient is an important modality in treatment planning. The importance of saliva cannot be underestimated, as this filtrate of serum which has a normal range of production of 0.5-1 L per day is important not only for teeth, but also protection from microbes, and aiding in digestion.

For example.

  • Microbes
  • Anti-bacterial -> Lysozyme, Histatins
  • Anti-fungal -> Immunoglobins
  • Anti-viral -> Cystatins
  • Teeth
  • Inhibition of demineralization -> Mucins
  • Remineralization -> Proline rich proteins, Ca, Phosphatase
  • Lubrication, viscoelasticity -> glycoproteins
  • Buffering -> Bicarbonate

Nature of Saliva

Furthermore, if a practitioner is to assess saliva, it is important to first understand its biological nature. For example, the normal flow rates of saliva change throughout the day (circadian rhythm), with often the highest production being in the mid-afternoon. This production can also be altered by food, thoughts and stimuli. Moreover, the flow is regulated by the autonomic nervous system, both parasympathetic and sympathetic.

Importance of Saliva

Importance of Saliva

Normal Values

Before saliva testing can be carried it out, it must be understood what is a health range and potential detrimental range of production.

Resting (unstimulated) Saliva

  • Is mainly from the submandibular glands
  • Typical walking flow rate is 0.3-0.4 ml/min
  • Resting volume approximately 1 ml.

Stimulated Saliva

  • Is mainly from the parotids
  • Results from mastication, taste, swallowing
  • Mean flow rate 1.6ml/min

Defining Salivary deficiency

  • Hyposalivation – Abnormally reduced saliva production
  • Xerostomia – feeling or dryness, patients with normal flow rates may complain of dryness
  • Salivary deficiency – Can be qualitative and quantitative

Importance of Testing

The importance of saliva testing is to access potential pathological causes, which may be causing a decrease in production. The importance of saliva testing and the relevance to dentistry is mainly to help a patient who is at high risk of caries. Other potential issues may also be necessary as well, such as aiding in digestion, and oral mucosa problems associated with xerostomia.

Quantity + Quality

The issue of quality and quantity is another important aspect of saliva tests, as a patient may have a normal range of saliva, although the quality of saliva may be such that its buffering capacity is inferior to normal levels, allowing for potential demineralization. Thus, a saliva function test is important to access for this potential decreased buffering rate

Identify a Cause: History

The importance of saliva testing is not only through means of direct measurements, but also through a thorough history, examination and special tests.

Not only is the decreased production of saliva important in the clinical assessment, but also the pH, which may be as a result of decrease production or due to separate factors which must be assessed to limit any loss of tooth structure, if critical pH of enamel (5.5) or dentin (6.5) is achieved.

There may be many reasons to account for a decreased production of saliva:


  • Through a through history and examination it may be particularly relevant to the dental health of though individuals who do know realize they are dehydrated such as special needs patients and the aged. Furthermore, healthy individuals may become dehydrated at time, and as a result be susceptible to decay. For example, strenuous physical activity, outdoor occupations and alcohol consumption may all decrease saliva production, through direct and indirect methods. If this is combine with a tip in the pH of the oral cavity, and individual may be at risk of potential decay

Salivary gland pathology

  • Often times, through special tests, such as sialograms and/or radiographs pathological conditions may cause a disruption to the production or flow of saliva.
  • This may first present with a patient complaining of pain, or through an extra oral exam show signs of asymmetrical facies.
  • Often times, patient may have had treatment for HIV, cancer or tumors and not realize that irradiation and chemotherapy can cause temporary and permanent damage to saliva production
  • Auto-immune diseases may present in history taking -> Sjogrens symdrome

Medical conditions

  • Psychological stress – can reduce saliva rate as the stimulation of sympathetic and parasympathetic NS may change flow rates.
  • Renal disease

Recreational drugs

  • Drug users can be particularly at risk as drugs can impede and decrease the production


  • Numerous medications can cause a temporary or permanent decreased production in saliva, as often there is an overlap in receptors.
  • Antidepressant, antihypertensives, and antipsychotics to name a few.

Thus, it is clear that numerous modalities may be the cause of patients decrease saliva flow, and the identification of the aetiological cause is important as it helps to not only potential address the situation direct, but also take precautionary or preventative measure to limit any unpreventable / or irreversible damage.

Modes of Testing + Interpreting Results

Current modes of testing saliva aim to access both the quality and quantity of saliva, through a number of clinical tests. This clinical tests are not often pathognomonic, but they often aid in classify a patient as high or low risk, which helps to treatment plan for either preventative or elevating measures.

  • Hydration levels -> Drying the labial mucosa and accessing the time for droplets to form (greater than 1 min High risk)
  • Visual appearance of US saliva -> Generally saliva appearing as a watery or clear fluid is often associated with health; whereas frothy or sticky saliva may signify a decreased production
  • pH of unstimulated saliva -> patient is asked to spit
  • Stimulated flow -> Chew for 5 minutes, low volume generally indicates dehydration or salivary gland function problem
  • Buffering capacity -> Quality, usually associated with low resting flow rate and or lack of buffering capacity

Indicators of Risk

  • The assessment may be an indicator of caries risk, but the test are more designs as a salivary gland function test to determine the health of salivary gland and an potential pathosis.
  • Recent research suggests resting saliva, and buffering capacity are better indicators of caries risk
  • Patient with caries on incisal edges or root caries are often consider to be potential salivary deficient


Finally and more importantly, saliva function tests are important to the patient as it allows for proper management and treatment planning.

Methods of promoting salivary deficiency:

  • Ensuring adequate hydration – drinking adequate amounts
  • Promote salivary gland function – chewing
  • Control of cariogenic diet
  • Control oral acidity – erosion, sensitivity, caries – CPP-ACP, bicarbonate mouthrinses, add milk
  • Promote remineralization – drink F-, toothpastes, extra F-, CPP-ACP
  • Oral hygiene
  • Restorative needs – high quality work, denture issues, amalgam over RC, GIC dissolve

Methods for management of Xerostomia:

  • Hydration
  • Chewing
  • Avoid astringents
  • CPP-ACP, CPP is hydrophilic
  • Adequate sleep
  • Avoid sugarless sweets.

If you wish for more information on teething please do not hesitate to contact Skygate Dental today on (07) 3114 1199 or 0406 579 197.