What is the role of salive, and is it important?
It is certainly important. In fact, saliva is one of the body's wonder liquids. About a litre of it is produced by the salivary glands every day, most of it during walking hours, less when sleeping.
Saliva has various functions. It activates the taste buds so that you can taste food, and it enables you to chew and swallow comfortably. Another important role is to neutralise acids produced by bacteria in the mouth. It also helps to control bacterial growth - mouth bacteria thrive and multiply on the carbohydrates, such as simple sugars and certain simple starches, found in food. The enzymes in the saliva help to breakdown food so that it can be dissolved and cleared out of the mouth. But saliva alone cannot keep the mouth clean; you still need to brush your teeth thoroughly every day.
Saliva also contains dissolved minerals such as calcium and phosphorus - the same minerals that make up the hard enamel outer surface of the teeth. These minerals are continually extracted from the saliva and bind with the surfaces of the teeth, keeping them hard, firm and healthy.