Diseases of digestive system

Infection

Infection means invasion of the body by micro-organisms. The most common sources of infection in dental practice are direct contact

With a patient's blood and saliva, flying particles of tooth or filling released during drilling. These sources of infection may enter the body through skin cuts or abrasions or the eyes, they may also be swallowed.

Even ancient people taught that body's first line of defense against infection was an intact surface, e.g. the outer of skin and the protective outer layer of mucous membrane. If infection had passed it the second line of defense started its action. It was the liquid secretion produced by the protective surfaces. The mucous membrane¹ and the salivary glands had produced saliva which neutralized some bacteria poisons and could kill some micro-organisms. Tears and sweat had a similar effect. The acidity of gastric juice killed many bacteria in food. The third line of defense is discovered now. It is immunity.