What are the clinical signs and possible causes of idiopathic progressive condylar resorption? Background The term "idiopathic progressive condylar resorption" has appeared in literature since the late 1990s. It is a rare disease that involves the resorption of the mandibular condyle and it is accompanied by a progres¬sive change of the bite position towards an Angle Class II [2, 3, 30, 46]. In the majority of cases, both condyles are affected. The patient group consists mainly of young women subsequent to orthodontic or surgical treatment. The average age is 20.5 years.