Is malocclusion associated with jaw dysfunction?

The maxillofacial region is an extremely important region of the body from birth, which is responsible for various functions such as sucking, swallowing, chewing, breathing and pronunciation. It has a complex structure and involves a variety of biological substances from the organ level to the molecular level. Since olden times, clinicians and basic researchers have been interested in the structural changes that occur when function is impaired, and numerous studies have been conducted. Nonetheless, the opposite direction, i.e., how structural disturbances, or malocclusion in orthodontics, affect function, has been less well understood. This is probably because of the methodological difficulties involved. In this review, we will first summarize the old question of whether dysfunction affects occlusion, focusing on masticatory function, especially jaw function, and then, based on this, we will outline a new concept, the proposition of whether malocclusion affects function, focusing on the "substances" that serve as the interface between structure and function.