Condylar resorption is a condition that affects the bone of the lower jaw. The condyles are knobs of bone which protrude from the sides of the jaw bone to form hinge joints with the skull, one on each side of the head. Each of these hinges is known as a temporomandibular joint (TMJ). Condylar resorption means that the condyles undergo condolysis, losing bone and shrinking, affecting the TMJ and the angle and position of the lower jaw. Often, this means that the gap between the upper and lower teeth swings apart, causing a changed facial appearance and sometimes making it impossible to close the front teeth together.
There are many known causes of condylar resorption, including infections, accidental injury and arthritis. It is not fully understood why one form of the condition, known as idiopathic condylar resorption (ICR), develops. The term idiopathic is used to describe it because, in idiopathic diseases, the cause is unknown. This kind of condylar resorption is known to affect women much more frequently than men, and it affects teenage girls most often, leading to dental disorders and musculoskeletal disorders. These changes can be distressing and uncomfortable, as they affect a person's looks and they can cause pain and biting difficulties.
Condylar resorption is associated with having orthodontic treatment or orthognathic surgery to correct the jaw bone. Dentists do not know whether this means condylar resorption is caused by these treatments or whether people who are likely to develop it are also more likely to require such therapies. They are also uncertain about the best form of treatment for the condition. Symptoms noticed by the patient can include a bite that changes, sometimes causing eating difficulties, and an altered facial appearance. There might also be joint problems, causing symptoms such as pain and cracking noises.
Traditionally, treatment for condylar resorption involves patients wearing synthetic guards over their teeth to take the pressure off their condyles. In cases where the condyles have been severely affected by resorption, they are removed and artificial replacements are fitted instead. Finally, surgery to the jaw is carried out to correct the patient's bite.
A potential problem with this treatment is that, in some cases, resorption can recur. Some dentists have proposed a different method, in which some joint tissue is removed before parts of the condyles are effectively repaired and repositioned. Then the surgeon carries out jaw surgery to correct the patient's bite. This procedure depends on there being enough of the condyles left to be salvageable.