Saliva Testing

April 21, 2015

  

Saliva is an important biological fluid that helps to maintain oral balance by reducing the effect of acid and promoting remineralization. It has multiple functions and protects the soft tissues and the teeth. Unfortunately, little attention is paid to it until considerable reduction in its volume or quality begins to cause damage. Saliva testing is a potent tool in the hands of the dentist which helps him to assess the condition of the saliva.

Purpose

Testing the quality and salivary flow rate helps to identify risk level even before the tooth decay begins. It is a part of the preventive dental care. It can also be used to understand the reason for the increasing rate of dental decay. Timely intervention can help to prevent decay, pain and the need for expensive restorative treatment later.

Parameters tested

Saliva testing consists of the following:

1. Flow rate of unstimulated saliva
2. Consistency (viscosity)of saliva
3. Unstimulated saliva pH
4. Volume of stimulated saliva
5. Buffering capacity of stimulated saliva

Procedure

The patient is advised not to smoke, eat or drink from one hour before the test. The patient should not have brushed his teeth or rinsed his mouth with a mouthwash during this time.

1. The test begins by examining the hydration status or flow rate of unstimulated saliva. The dentist pulls the lower lip outward and dries the inner side with a gauze. Drops of saliva should become visible at the minuscule holes of the minor salivary glands which are located there. The time taken is an indication of the hydration status.
2. Viscosity of the saliva is judged by examining it visually.
3. This is followed by testing the pH of unstimulated saliva. The saliva is collected in a cup and a test strip is dipped in it for 10 seconds.
4. Patient is asked to chew on wax and the stimulated saliva is collected over 5 minutes.
5. A drop of stimulated saliva is put on the test pads of the buffer test strip and changes are observed after 2 minutes.

Interpretation

1. Flow rate of unstimulated saliva: If droplets become visible within 30 seconds, the flow rate is high, if it takes 60 seconds, it is normal, if it takes more than 60 seconds then it is less than normal.
2. Consistency (viscosity) of saliva: If it is watery and clear, it is considered normal; frothy with bubbles implies increased viscosity while sticky and stringy saliva means low production and inadequate water.
3. Unstimulated saliva pH: The pH below 6 is too acidic while a reading between 6 and 7 is mildly acidic, a reading of 7 or above is ideal.
4. Volume of stimulated saliva: Greater than 5 ml is normal while quantity between 3.5 to 5 ml is moderately low. Anything beneath it is cause for concern.
5. Buffering capacity of stimulated saliva: A reading of below 5 indicates very low capacity, between 6 and 9 points is also on the low side while 10 or above indicates normal buffering or acid neutralizing capacity.

Since a lot of factors affect saliva production, interpretation of results needs a careful assessment of the patient’s medical history, diet as well as lifestyle.

Dentists can also order pathogen specific testing that looks for certain bacteria in the saliva known to be responsible for cavities. Besides this, saliva testing has also emerged as a potent diagnostic tool that helps to detect certain medical conditions.

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