Simply put, the oral cavity refers to the interior of the mouth. It is bounded laterally by the cheeks, superiorly by the palate, inferiorly by the floor of the mouth and anteriorly by the lips.
For the most part, the oral cavity is filled by the tongue. The area between the teeth and the lips or cheeks is also called oral vestibule. In a human oral cavity there can be more than 300 species of bacteria, which live in a natural balance without harming the individual. Diseases usually only occur when this balance is disturbed. Caries and gingivitis are among the most common diseases of the oral cavity.