How Bones and Teeth Shape the Face
Bones are the framework for the face. The size and position of facial bones determine how well the teeth fit together. Together, the positions of the jaws and teeth affect chewing, speaking, and the working of the jaw joint. The jaws also hold and support soft tissues, such as the muscles, lips, and tongue. And of course the jaws and teeth are factors in the face's shape and appearance.
How the Jaws Work
The lower jaw holds the tongue, which moves freely as you speak and eat. The upper jaw shapes the floor of the nasal cavity, allowing normal airflow. Normally, muscles are evenly developed on both sides of the face.