Managing the Arthritic TMJ

The natural course of a TMJ disk dislocation disorder consists of initial pain followed by adaptive remodeling as part of a healing process that makes the damaged TMJ once again function like a normal TMJ. The reshaping of the bones (remodeling), which can be seen on X-rays, creates a diagnosis of arthritis, but it represents a successful adaptation. The joint has healed. Subsequently, some jaw muscle symptoms may persist as a subset of postural muscle strain, because the mandible is part of the postural system; and some ear symptoms may persist long after the cause is gone, because the inner ear does not recover well from injury; but TMJ inflammation is rare. 

 

The successful adaptation is due to fibrosis of the retrodiskal tissues. These tissues, that once provided blood and nerve supply to the TMJ from the area just behind its disk (retrodiskal area), get pulled by the dislocation of the disk into the former disk space, where they responded to chewing forces by converting into a pad of tough scar tissue called a pseudodisk. Pseudodisks look and function so much like normal disk tissue that, for many years, surgeons mistook them for normal disk tissue and routinely diagnosed the disks they removed as elongated; until researchers pointed out that TMJ disks are made of collagen and cannot elongate, and microscopic examination of these reportedly elongated portions of the dislocated disks contained remnants of blood vessels - proof that these areas were not originally disk tissue but fibrosed connective tissue. The conversion process is pictured below: 

 

Oral orthopedic appliances worn during sleep, when the jaw system undergoes its nightly workout, can facilitate pseudodisk formation so that it occurs within days or weeks rather than years. The type of oral orthopedic appliance that you need depends on the condition of your TMJs, the state of your jaw and neck muscles, and your facial growth pattern. If your jaw muscles were held tightly for a long time to protect an inflamed TMJ, they may have undergone an anatomical tightening called contracture, so restroring their normal resting length requires forceful stretching. If they avoided using chewing forces for a long time to protect an inflamed TMJ, they may have undergone atrophy, so returning their normal strength requires exercise. Long-term treatment should optimize the slow continual jawbone growth of adulthood to prevent the symptoms from returning by nightly wear of an oral appliance that redirects the forces of nocturnal bruxism to gradually remove the restrictions to healthy facial growth, which are ultimately responsible for the strains that cause the tissue damage. The vast majority of patients need treatment that advances the lower jawbone and expands the upper jawbone, but the proportions depend on individual facial growth patterns.

 

Healthy facial growth requires a stable natural bite. For the TMJs to acquire a good fit between the opposing bones, the natural bite must provide a consistent and stable bracing platform for the mandible as well as smooth consistent chewing pathways in and out of it. If the bite keeps shifting, the bony contours of the TMJs keep remodeling to try and fit a moving target. In many people with TMJ disorders, the bite has been destabilized by a change in the height of a condyle (remodeling), and restabilizing it requires moving teeth, grinding down high spots, and/or building up low spots. In a few cases, restabilizing a bite can require significant dental work such as crowns or orthodontics. These options are explained further in THE ROLE OF THE BITE under the tab TMJ DISORDERS.

 

SURGERY of the TMJ can be risky, because failures can be disasterous due to a build-up of scar tissue can prevent natural adaptation. For that reason, open TMJ surgery should be considered a last resort. Closed surgeries, such as arthroscopy and arthrocentesis, in which tubes and inserted into the joint to flush out the inflammatory tissues and sometimes also to perform some manipulation of the joint tissues, are safer; but they cannot yet be used to recapture a dislocated disk.

   

CONCLUSION

Having an arthritic TMJ does not condemn you to a lifetime of pain. Many people have TMJs that are technically arthritic, but they have fully adapted and are no longer causing inflammation or triggering muscle guarding. Therefore, their TMJs do not need treatment. When the TMJs or the jaw and neck muscles need treatment, oral orthopedics can provide relief of the symptoms within days and stimulate the facial growth needed to prevent them from ever returning.