Saliva plays a crucial role in maintaining oral health and is particularly important in the prevention of dental cavities (caries). Here are the key functions of saliva that contribute to this protective role:

1. Neutralising Acids:

- Saliva helps neutralise acids produced by bacteria in the mouth, which are responsible for breaking down tooth enamel and causing cavities. By buffering these acids, saliva protects enamel from erosion and decay.

2. Remineralisation:

- Saliva contains minerals such as calcium and phosphate that are essential for the remineralisation of tooth enamel.

- This process helps repair early damage to teeth from acid attacks, thus preventing the formation of cavities.

3. Washing Away Food Particles:

- Saliva helps in cleansing the mouth by washing away food particles and debris.

- This reduces the amount of substrate available for harmful bacteria to feed on, thereby reducing the risk of cavity formation.

4. Antimicrobial Properties:

- Saliva contains antimicrobial agents like lysozyme and lactoferrin which help control the bacterial population in the mouth.

- By keeping the growth of cavity-causing bacteria in check, saliva helps prevent tooth decay.

5. Aiding in Digestion:

- While not directly related to cavity prevention, saliva aids in the digestion of food by breaking down carbohydrates through the enzyme amylase.

- Efficient digestion can indirectly contribute to oral health by minimising the amount of food residue that bacteria can utilise.

6. Forming a Protective Coating:

- Saliva forms a protective coating on teeth and oral tissues, providing a barrier against harmful substances, including acids.

7. Maintaining Oral pH:

- Saliva helps maintain a neutral pH in the mouth, which is less conducive to the growth of harmful bacteria that thrive in more acidic environments.

Given its important role in oral health, conditions that reduce saliva production, like xerostomia (dry mouth), can significantly increase the risk of dental cavities and other oral health problems. Therefore, ensuring adequate saliva flow, either naturally or through therapeutic means, is vital in maintaining oral health and preventing cavities. Regular hydration, avoiding dry mouth-inducing medications where possible, and stimulating saliva production with sugar-free chewing gum or lozenges are common methods to support saliva's protective functions.