A Three-Dimensional Evaluation of the Lingual Structure and Its Relationship with the Upper Airway Across Various Skeletal Classifications

Orthodontic diagnosis and treatment planning has evolved from hard tissue paradigm to soft tissue paradigm. However, it is not spared from controversies. One such controversy is 'Function determines form v/s Form determines function'. Functional matrix theory proposed by Melvin Moss states that "the origin, development and maintenance of all skeletal units are secondary, compensatory and mechanically obligatory responses to temporally and operationally prior demands of related functional matrices. This emphasizes on 'Function determines the form' concept. Tongue being the major soft tissue component i.e, the functional matrix of the oral cavity, faulty behaviour of the tongue may be associated with the development of dental malocclusion and jaw deformities.1 According to the "Form determines the Function", decreased space between the mandibular corpus and the cervical column may lead to changes in posture of the tongue and soft palate posteriorly, which can lead to impaired respiratory function during the day1. It may also cause possible nocturnal problems such as snoring, upper airway resistance syndrome, and obstructive sleep apnea.