Gnathology is the study of the masticatory system, including its physiology, functional disturbances, and treatment. It is studied in some dental schools in the United States. Because it is not part of the training of all dental schools, most dentists learn through post-graduate study clubs. Gnathology is accurate dentistry, verifying the work as it progresses, applying all well founded gnathological principles, and rechecking the work continually. A professional specialised in this field is referred to as gnathologist.