High functional risk is evidenced in damage to the jaw joints, muscles, or teeth that exceeds what is normal for the person’s age. High functional risk occurs when there has been excessive loading in a compressed period due to what I described in Part 1 of this blog series as macro trauma from an impact event or micro trauma from chronic parafunction.

To manage functional risk and slow down the attrition we are observing, dentists adjust the patient’s occlusion to reduce that load. What are our goals in changing the occlusion and why does changing occlusion work well in most cases?

Functional Risk Management Goals

Whether we are managing functional risk with a bite splint, orthodontics, occlusal adjustment and/or restorative dentistry, we want to:

• Stabilize joints
• Stabilize muscles
• Stabilize dentition
• Ensure predictable restorative outcomes

We want to stabilize the joint anatomy, the structures of the temporomandibular joints, and reduce the activity of the elevator muscles because they are what overloads the joints and teeth and can be used with so much force that the muscles injure themselves. We also want to slow down the rate of damage to the dentition and move that rate back to a more age-appropriate pace. Often, we need to reorganize a patient’s occlusion to manage occlusal forces to ensure predictable restorative outcomes that last.

Why Changing Occlusion Works

Dr. Bob Barkley said, “Our job as dentists is to help our patients get worse at the slowest possible rate.” And that is what occlusal therapy does. When we change the occlusion, we are minimizing the force applied across the tops of the teeth and redistributing the force applied across the tops of the teeth.

The Science Behind This

In the dental literature, most studies are based on electromyographic activity. The patient is given a false occlusion on an appliance and the occlusion is altered. EMG activity is read when the teeth touch under many variations. By adding a premolar contact, the activity of the elevator muscles doubles. When a second molar contact is added, the activity of the elevator muscles rises five to ten times. A key article is Influence of variations in anteroposterior occlusal contacts on electromyographic activity by Arturo Manns, et al.

The EMG studies have demonstrated posterior tooth contacts produce the greatest load, so to minimize load, we eliminate posterior tooth contact. For most patients, we can’t get them to immediately disclude on their centrals, but we can get them to disclude on the canines, and we want to pass that off as fast as we can to the centrals. The term canine guidance or anterior guidance refers to the absence of posterior contacts. Instead of saying canine guidance or anterior guidance, many people use the term immediate posterior disclusion.

Note: The two-to-ten-times-more force recorded on an EMG study appliance is likely much lower than the force applied by muscles adapted to para-functioning over years and years. Those adapted muscles have become larger, more fibrous, and can generate more force.

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. This will be revisited in Part 3 – Management Modalities.

I like to think that I have three things I provide to my dental patients:

1. Risk assessment – helping them understand and fully own risk factors for their long-term dental health
2. Risk management – helping them understand what they could do to manage that risk
3. Damage repair – definitively treating a risk that was not completely managed

Many dentists do not pay attention to occlusion unless it is a problem for the patient or unless it becomes an issue in treating the patient. As I tell dentists in Essentials 1: Aesthetic& Functional Treatment Planning, assessing functional risk is as important to me as assessing other risks, such as caries or periodontal disease. I want to find the signs of functional risk, so if a patient has higher risk of damaging teeth from excessive loading, I can help the patient understand that risk and the options for managing it.

Functional Risk Assessment

In a previous blog, Occlusal Wear Part 1: Is it advancing? How fast?, I shared the mental game I play with every patient and the ways in which I document wear changes. With every patient, I ask myself, “Is the wear I see on the teeth normal for the patient’s age? Is it advancing at a pathological rate?”

I categorize patients in one of three functional risk categories:

• Mild
• Moderate
• High

The patients I place in the high-risk category are those whose functional wear and tear is more than it should be for their age. Their teeth are breaking down noticeably faster than the average rate.

In my practice, we measure from the CEJ to the incisal edge of several teeth with wear. We take the measurement on the mid-facial and record it on the patient’s perio chart. At subsequent appointments, we can now repeat these measurements and have clear data showing that the process is continuing. Other great ways to document tooth wear are with photography and digital impressions. We compare scans months later and get a precise measurement of the change.

What causes someone to be at higher functional risk?

A lot of our patients have true TMD. What causes them to become symptomatic–where they have muscle issues, limited range of motion, jaw fatigue or joints trauma, myofascial pain, and they are breaking down their teeth? There are two primary causes: macro trauma and micro trauma.

1. Macro trauma can cause a temporary injury to the temporomandibular system that then sets up chronic problems in the joints and muscles. This could be due to a car accident or sports incident. I have a macro-trauma patient who was hit was a lacrosse stick, another that was elbowed in the jaw during a basketball game, and a cheerleader who fell off a human tower.
2. Micro trauma is what dentists call parafunction. This occurs when people put their teeth together outside the normal ways teeth touch when eating, speaking, and swallowing. We think of clenching (both static clenching and power wiggling), grinding, and tapping teeth together. We think of patients who bite their fingernails or chew on the inside of their cheeks or lips. There are lots of types of parafunctional activities. The force generated by the elevator muscles and how much of the time the muscles are overloaded leads to muscle symptoms. Accumulative force causes the excessive wear we see on teeth and damage to jaw joints.

To dentists, I say:

There are many people who have textbook malocclusions, and yet they have healthy teeth and joints. They don’t touch their teeth together outside of eating, speaking, and swallowing. There are many people with perfect occlusions who have TMD symptoms. Malocclusions don’t cause functional risk. Malocclusions don’t cause TMD. The essence of the problem is not how the teeth touch but how much they touch.

To patients with micro trauma, I say:

“You are tougher on your teeth than most of my other patients.” Staying away from psychologically negative words like clenching, grinding, and parafunction, I give them the word tougher. And I say, “You are missing more tooth structure than most people of your age.”

It is helpful for them to have this explanation before I recommend risk management strategies and pre-emptive restoration of teeth before they break.

An analogy I use with patients is the human knee. Knees don’t commonly wear out until someone is 60 to 70 years old, but long-distance runners can wear them out much earlier in life with the repetitive force of running. Our patients with parafunction put a lifetime’s worth of wear and tear on their teeth and their muscles and jaw joints in a compressed amount of time. Like a long-distance runner, their masticatory system suffers micro trauma.

It’s helpful to give patients words and analogies (like knees and car engines that wear out due to faster than normal wear and tear). I’ve had patients say to me, “I don’t like having to replace this crown, but as you said, I am tougher on my teeth than most people.”

Ask One More Question

One of the ways I have learned to Stay in the Question is to practice asking one more question before I give information. Learning to ask one more question has helped me to be more effective in several ways

1. The practice of asking one more question helps us save time.

My experience is that we spend a lot of time giving patients information they may not want or need. We can waste our time and theirs by giving information they have not asked for.

There was a time when if a patient asked me if x-rays were “really” necessary, I would go on at great length about the value of the radiographs, what we could see on them, and what we might miss if we didn’t take them. But I learned to respond, “It sounds like you might have some concerns about having x-rays,” and ask, “What is your concern?” By asking one more question, I was able to answer the patient’s question or concern very precisely and quickly.

2. Staying in the questions helps us understand what the patient wants from us.

Patients don’t always know how to communicate with us to get their needs met. They ask what they know how to ask. Sometimes their question is “Will my insurance cover that?” Sometimes their question is “How long will it last?” or “Will it hurt?”

Asking a follow up question to any question or concern they express allows us to better understand their needs and expectations. If a patient asks, “Will it hurt?” I could reassure them I will be as gentle as possible. Alternatively, I could say, “It sounds like you are concerned about the pain of this procedure. Have you had a painful dental experience in the past?” Responding to a specific fear will always be more powerful than a general reassurance.

3. Asking one more question allows us to give information clearly, to give information that is useful to them.

After seeing patients over years, it is easy to fall into giving the same information repeatedly. We all have our scripts we fall back on that describe a particular disease or procedure. Having a ready-made script may seem efficient but in the long run it can cause us to miss opportunities to be more effective with our patients. We can spend a lot of time giving them reasons why we think they should have treatment instead of providing more precise information relevant to their needs and their wants.

Aristotle said, “The fool persuades me with his reasons. The wise man persuades me with my own.” We don’t need to guess how to persuade our patients. I’ve learned that, when I stay in the question, patients tell me exactly what they need from me to be able to make decisions.

4. Asking one more question creates an opportunity to build trust.

There was a time when I thought having all the answers for my patients would make me seem competent and gain their trust. I’ve come to understand that I will never have all the answers and that, in dentistry, it is just as important for patients to trust our motives as it is for them to trust our competence. When we take their questions and concerns seriously, follow up with genuine curiosity, and listen deeply to their responses, they are more likely to feel our care and concern. They are more likely to trust that what we want is what is best for them.

One of the most important things I aim to do is create clear expectations for my dental patients. Over the years I have intentionally tried to shift my language from discussing “treatment” to “management” when talking with patients who have dental risk factors that will persist throughout life. Perhaps, the following short discussion will empower you to do the same.

By being intentional about this, we can:

• Reduce patient frustration,
• Avoid patients thinking we have failed them,
• Boost their confidence that we are working together to address their oral health problems, and
• Inspire them to try management therapies and return to therapies that helped in the past when there are flare-ups.

When I describe something as a treatment versus describe something as a management therapy, I inform my patients about the difference and explain why management therapy may or will never eliminate the underlying cause of their oral health issue — but by continuing to manage their issue therapeutically throughout life, they will hopefully reduce discomfort and disease.

I make a clear distinction that treatment fixes a problem, and in their case, the problem may not be fixable, although it can be managed. For example, I focus on this when the patient is truly at high risk for periodontitis. This is a patient who has suffered from bone loss and has a body that is highly reactive to the bacteria in the inflammatory disease known as periodontitis. I also focus on this when the patient has significant TMD issues.

When I tell a patient, that we are going to treat something, the use of the word “treat” sets the expectation that the problem will be eliminated. That is very different from a management strategy that helps to reduce the symptoms and/or the continued degradation of their oral health. When we tell patients we are going to do scaling and root planning and we’re going to “treat” their periodontitis, it can be really challenging for them when we recommend that they do additional periodontal therapies.

When we think about periodontal risk, functional risk, and caries risk, the reality is that risk is a bell curve. There are some people whose risk factors are easy to manage, and some people whose risk factors are very challenging to manage. We need to help patients understand that when they have certain risks, certain disorders, there really is no treatment. What we do have is a lot of therapeutic modalities that can help manage the damage, manage the symptoms. Sometimes these modalities are so effective that it appears the disorder has gone away.

We need to recognize and the patient needs to know that the disorder really has not gone away and can surface again. With clear expectations, our patients (and we) do not have to experience disappointment and frustration. Instead, we can have supportive, empathetic conversations, and move ahead with restarting therapies and trying new ones.