TMJ Surgery: The oral orthotic or bite splint

One of the most common dental management tools for “TMJ” is the oral orthotic or “bite splint”.  The orthotic can be a very useful tool for pain management if a patient has periodic bouts of pain due to joint inflammation or swelling from various causes. These would be the majority of patients managed conservatively or non-surgically.  The analogy in orthopedic medicine would be the individual who whould wear a joint orthotic (knee bracing, spinal bracing etc.) for joint support, pain or protective management and did not yet exhibit joint pathology meriting surgery.

  Bite splints can be fitted to the upper or lower teeth.  Often the concept of effectiveness is that these are used at night to manage night time tooth grinding or clenching (bruxism).  Many times they are constructed to fit on the upper teeth.  Our practice generally will employ an orthotic to be fitted to the lower jaw. Many of  our patients with documented joint derangement or other arthritic processes will have employed a bite splint for years.  Surgical patients will  need continuous wear when referred to us during phases of pre-operative pain and diagnostic  management. The orthotic that is applied to the teeth on the lower jaw  does not interfere with speech and other functions ( when a patient is require to wear the appliance at work, school etc) as much as a splint that adapts to the teeth in the upper jaw.  

  With this group of patients,  MRI documents that a TMJ can be decompressed with an oral orthotic and slight forward posture of the lower jaw to a near edge to edge incisor teeth postion.  This can be successful in improving  joint stability and pain.  However, if and when the patient removes the orthotic to function normally and chew food, if pain and joint instability return under these orthopedic loads, this is significant.

I find that many patients and dental providers can be perplexed when all appropriate efforts to manage a patient with splint therapy fails.  If a significant boney impingement process exists and has not been diagnosed, splint therapy will not be successful.

The following coronal MRI scan shows such a situation.  Here, the MRI has been taken with the orthotic in place in the mouth.  The inner 2/3 of the TMJ disc/capsule has been decompressed, however, even with the splint in place, a severe impingement can not be overcome.  Note in the lateral 1/3 of the joint space that there is no visible fibrous tissue disc signal of similar with of the disc in more central and medial aspects.  This joint would still exhibit significant orthopedic instability, be painful particularly with jaw movement to the effected joint side (lateral jaw movements) and could not be loaded with routine chewing force loads.

Protocols for determining surgical intervention involve this process or treatment protocols.  Whenever a patient has worsening joint instability, pain, etc. and continuous wear of a orthotic is not successful for up to 4-6 weeks, we recommend MRI imaging with and without the oral orthotic in place.  If the MRI documents continued existence of the derangement in sagittal views (Wilkes II-III) and the coronal view demonstrates a significant impingement with the orthotic in place. we will recommend surgical arthroplasty.  In this particular case, the patient was 27 years old.  Arthroplasty and removal of the impingement with disc/capsule repair was successful.  The patient eventually was able to discontinue any further day time use of the appliance and eventually recovered to be able to enjoy a regular diet again with minimal restriction.

In an operated patient, I recommend continued use at night indefinitely.  Bruxism is generally not a reversable phenomenon and is one aspect of long term care that must be acknowledged and respected.  Bruxism can generate joint loads that are higher and more sustained than some of those required for eating.  Therefore, we want to construct a surgical and post surgical orthotic with MRI proven abliity to increase joint space and take load off the disc/capsule.