Functional Appliances Are Good for the Jaw Joint

Functional appliances can make a big difference in your appearance. A receding chin and/or a pronounced overbite caused by malposition or underdevelopment of the lower jaw can make you very self-conscious. But functional orthodontics can correct this, repositioning and/or expanding the lower jaw so that you get a more attractive profile.

But some people have been concerned that there was a serious price to pay for this improvement in appearance. The concern was that functional orthodontics might be putting stress on the temporomandibular joints, leading to joint damage and temporomandibular joint disorder (TMJ). But now a new review helps put those fears to rest: studies show that there is no temporomandibular joint damage or TMJ symptoms related to treatment with functional orthodontics. In fact, functional orthodontics may help people with some forms of TMJ.

A Comprehensive Review

This new article, published in the Spanish journal Medicina Oral, Patologia Oral, y Cirugia Bucal, was designed as a comprehensive review of all published research on functional orthodontics and its impact on the temporomandibular joints.

TMJ pain

Reviewers searched a large number of databases to find all relevant information published from 2000 to 2015. They initially found 401 articles, but after discarding duplicates and articles that didn’t really answer the question, 29 studies were identified. Eight of these studies were ultimately discarded because they were either of low quality or just used redundant data. The remaining 21 articles were consolidated to determine aggregate findings.

They determined that there were two main findings in these articles. First, treatment with functional appliances tended to move the condyle (the rounded projection of the mandible that fits into the depression in the temporal bone) forward. This led to some reshaping of the condyle and the vertical bone at the rear of the jaw, called the glenoid fossa. Second, there were no adverse effects of functional orthodontics on the temporomandibular joint. They found that functional orthodontics could actually help patients who had the cushioning cartilage of the jaw joint pushed forward in front of the condyle.

Having the cartilage disc in front of the condyle is responsible for jaw popping and clicking (called disc displacement with reduction–the disc gets compressed or “reduced” when it pops back into place). If not treated, it can lead to a limited ability to open the jaw or complete inability to open the jaw (called disc displacement without reduction–the disc doesn’t get compressed because it doesn’t go back in place and instead inhibits the motion of the jaw).

Limitations of the Study

However, researchers were careful to note that there are several limitations of their review. Mostly, it’s that their review is limited by the quality of the published studies. Most of the studies were relatively small with a few dozen patients. The largest study only had 138 patients.

The studies were also lacking in randomized clinical trials with long-term follow-up. Inconsistency of measurements was another problem, and the fact that researchers used different appliances could have introduced uncertainty. Most focused on the Herbst appliance, but some used Twin Block and others.

Are You Ready to Get a Better Profile?

If you are considering orthodontic treatment with a functional appliance in River Edge to improve your profile or your bite, we can help. Please call 201-546-8512 today for an appointment with TMJ dentist Dr. Marlen Martirossian at River Edge Dental.