The term "osteoarthritis" has classically been defined as a low-inflammatory arthritic condition. The term "osteoarthrosis," a synonym for osteoarthritis in the medical orthopedic literature, has recently come to be identified in the dental/temporomandibular joint (TMJ) disorders literature with any noninflammatory arthritic condition that results in similar degenerative changes as in osteoarthritis. The term "idiopathic condylar resorption," also known as "progressive condylar resorption," is described as a dysfunctional remodeling of the TMJ manifested by morphologic change, decreased ramal height, progressive mandibular retrusion in the adult, or decreased mandibular growth in the juvenile. This article discusses the diagnosis and management of osteoarthritic TMJ disorders and idiopathic condylar resorption.