Treating Temporomandibular Disorders in the 21st Century: Can We Finally Eliminate the "Third Pathway"?

Within the orofacial pain discipline, the most common group of afflictions is temporomandibular disorders (TMD). The pathologic and functional disorders included in this condition closely resemble those that are seen in the orthopedic medicine branch of the medical profession, so it would be expected that the same principles of orthopedic diagnosis and treatment are applied. Traditional orthopedic therapy relies on a "Two Pathway" approach involving conservative and/or surgical treatments. However, over the course of the 20th century, some members of the dental community have created another way of approaching these disorders- referred to in this paper as the "Third Pathway"-based on the assumption that signs and symptoms of TMD are due to a "bad" relationship between the mandible and skull, leading to a variety of irreversible occlusal or surgical corrective treatments. Since no other human joint is discussed in these terms within the orthopedic medicine communities, it has become progressively clear that the Third Pathway is a unique and artificial conceptual creation of the dental profession. However, many clinical studies have utilized the medically oriented conservative/surgical Two-Pathway model to diagnose and treat TMD within a biopsychosocial model of pain. These studies have shown that TMD comprise another domain of orthopedic illness that requires a medically oriented approach for good outcomes while avoiding the irreversible aspects of the Third Pathway. This review presents historical and current evidence that the Third Pathway is an example of unorthodox medicine that leads to unnecessary overtreatment and further proposes that it is time to abandon this approach as we move forward in the TMD field.