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.

Have you ever had a night guard or other full coverage dental device come back with contact only in the posterior or heavy in the posterior? It is a fairly common phenomenon. And it is a big challenge when doing two-jaw hybrid surgery and placing the temporary restorations on the day of the surgery.

I became aware of this big challenge when my oral surgeon came across the parking lot one day to discuss the upper and lower hybrid case of one of our mutual patients. This was the first hybrid case we would be doing together. He had been using a company with a software platform that does his implant planning and digital setup, and then produces his surgical guides and provisional restorations. It can even produce the final restorations. He related to me that when he tries in the initial prostheses, he always finds they are heavy in the posterior.

So, I asked him, “When they ask you for records, what do you send them?” He said they request either an upper and lower scan, or upper and lower BPS impressions, or upper and lower models. They also want a bite record and a shade. As he went down the list, something was missing that has to do with heavy posterior contacts.

Whether it is premade upper and lower provisional restorations when you are doing extractions, implants, and hybrids — or it is a nightguard you get back from the lab or Invisalign trays that you receive from Invisalign, there are occasions when we find prostheses are heavy on the posterior contacts. Sometimes there are no anterior contacts. That’s because, across the board, prostheses need to be fabricated knowing the arc of rotation, which is the distance between the hinge axis at the center of the condyle and the upper anterior teeth.

A full arch impression taken without a facebow transfer, either hand articulated or with a bite registration only over the prepared teeth, only provides the same information about maximum intercuspal position as a triple tray. If we mount the full arch impressions on a simple hinge articulator, the articulation used does not represent the arc of rotation. If we are digitizing the impressions for a digital system, we also are missing this essential piece of diagnostic information. We must have impressions mounted on an articulator with a facebow or dental-facial analyzer (DFA).

I explained this to my oral surgeon who became concerned he would not be able to deliver this information to the implant planning company he was using. But this story has a happy ending. He called the company to learn if they could use articulated models mounted with a DFA or facebow. It turns out they much prefer this! And they told him the specific articulator systems for which they have corollaries in the digital world. If he sends the models mounted on any of these, they can digitize them and know the arc of rotation.

Those who have been in my presentations have heard this many times before. The more esthetic and functional information we send to the laboratory the higher will be our ability to efficiently manage the functional and esthetic issues of the case precisely. A lesson we can learn from this story is the value of conversing with the specialists on our interdisciplinary teams and in our interdisciplinary study clubs about the importance of capturing and communicating the arc of rotation. If a laboratory is not requesting this information, have a conversation with the laboratory.

The primary purpose of Panadent’s DFA or any of the earbow/facebow systems is to capture this critical piece of information we call the arc of rotation. There is other information these systems capture but the arc of rotation is critical in establishing proper occlusion. I’ve written about Panadent’s DFA in a previous blog. For an in-person, hands-on lesson in the dento-facial analyzer, we invite you to attend our Essentials 1 Pankey course. You can also watch this video for a quick refresher.