Functional Risk Part 3 – Occlusal Therapy
Why Occlusal Appliance Therapy Is My First Step Prior to Ortho, Equilibration, or Restorative
Occlusal changes on an appliance are easy and reversible. An appliance can immediately reduce elevator muscle activity and give the patient relief. The patient also experiences what changes to their tooth contacts could provide for them long term. We can test the changes that would be made by ortho, equilibration, and/or restorative.
As reviewed in Part 2 of this series, our goals are to stabilize the joint anatomy and reduce the activity of the elevator muscles because those muscles are what overload the joints and teeth. We also want to slow down the rate of damage to the dentition and move that rate back to a more age-appropriate pace. We also may need to reorganize a patient’s occlusion to manage occlusal forces to ensure restorations that last.
Removing Posterior Contacts Does Not Work for Every Patient
Over my years of clinical practice, I have found that changing the occlusion does reduce functional risk for most patients. But we all have patients with perfect occlusion who present with TMD symptoms. We have some patients who continue to parafunction after we move them into immediate posterior disclusion.
Studies show that proprioception causes the elevator muscles to engage in only 80 to 85% of the population. This means that when the brain receives the signal that teeth are touching, the brain elevates the masseter muscles in 80 to 85% of people. Tooth contact is the trigger. Because this proprioception does not occur for 15 to 20% of the population, it is not the universal trigger for excessive loading.
Over my years in clinical practice, I have learned there is nothing I can do that is 100% dependable to stop a patient from para-functioning. Some of my patients continue to excessively load after posterior contacts are removed. Their functional risk does not diminish.
If we cannot reduce elevator force and redistribute force enough on an occlusal appliance to eliminate or at least relieve TMD symptoms, then occlusal therapy via ortho, equilibration, or restorative will not satisfactorily help the patient. We will need to turn to other forms of therapy.
Other modalities I use are BOTOX to deactivate muscles, massage therapy, and physical therapy. There are also systemic medications, cold lasers, and TENS therapy we can use to reduce the activity of the muscles or reduce inflammation in the muscles and joints. Sometimes one modality will alleviate symptoms for a while and when symptoms return, we can try it again or try another modality.
An Exercise to Identify the Patients Who May Not Benefit from Occlusal Therapy
You can do what I call a poor man’s EMG on yourself by placing your hands on your masseter muscles. Put your back teeth together, clench and release, clench and release, clench and release to see how much masseter activity you have. Then move your teeth into protrusive edge to edge and try to clench a little bit, making sure your back teeth do not touch. If you now have a posterior tooth touching in the edge-to-edge position, then put a pencil or pen between your front teeth to separate your back teeth.
With no back teeth touching and contact on the centrals, try to clench and release two or three times while feeling your masseters. Most of you will find your masseters do not move or move a lot less when no back teeth are touching. Some of you, even with your back teeth separated, can still clench in protrusive and can still increase the muscle activity almost the same amount as when your back teeth touch.
I do this exercise with my patients, but when they move into protrusive, I put a bite stop over their front teeth or have them bite on a Lucia jig we have lined for their bite registration. If you do this test with your patients, you can use an EMG or feel the muscle activity with your hands.
If the patient can still generate almost the same force or the same force with their back teeth separated, you have identified one of the around 15% of people who might not benefit significantly from occlusal therapy. You’ve also identified someone who might not do well on an anterior-only appliance because, if they can generate that same force on just two teeth, they are at risk for those teeth becoming sore and moving.
Interested in Learning More?
The Pankey Institute Essentials courses and multiple focus courses include hands-on exercises and over-the-shoulder training designed to help dentists develop mastery in reducing functional risk and treating TMD symptoms.