"Gnathos", meaning jaw and "ology", meaning study of, or knowledge of. One who adheres to gnathological principles is practicing dentistry with respect to the entire stomatognathic complex and understands how the dynamics of mandibular movement have a profound effect upon the anatomy of all the teeth and their stance in the dental arches. 

The temporomandibular joint (TMJ) acts like a sliding hinge, connecting your jawbone to your skull. You have one joint on each side of your jaw. TMJ disorders — a type of temporomandibular disorder or TMD — can cause pain in your jaw joint and in the muscles that control jaw movement.