Choosing an Oral Appliance: Force Distribution and Does The Airway Matter?

For many years the go-to oral appliance to address sleep bruxism (whether it be in the form of clenching and/or lateral grinding) has been a full-coverage flat plane maxillary or mandibular appliance. Like all other varieties including anterior deprogrammers, these appliances do not stop the bruxism activity but instead dampen the impact. This commonly leads to fewer morning jaw symptoms and often the healing of injured jaw muscles and joints. These appliances often need adjustment over time to assure maintaining their protective function.

Over time the benefits achieved with these appliances could drop off based on external factors like sleep quantity and quality and co-morbid pain problems inclusive of migraines, tension headaches and neck-related problems. Generalized life tension certainly can play a role in morning jaw symptoms, as well.

Though the flat plane appliance has helped countless patients throughout the world over many years, there has been recent commentary suggesting that maxillary flat plane appliances are not predictably helpful and that they can put the patients health at risk due to their impact on tongue position and the airway.

With this blanket commentary I will need to take exception.

As always, treatment decisions must be based on careful history taking, examination, supportive testing and clinical judgment. In the absence of these four critical pieces, making a wrong diagnosis is easy and can lead to treatment inadequacy or complications. In this light, if a patient’s profile suggests an airway problem, then investigations should precede the process of choosing one appliance over another.

However, if the patient‘s first encounter in the office includes?an unremarkable sleep and medical history, unremarkable data collected on?screening tools?(such as the Epworth Sleepiness S?cale,?STOP-Bang Questionnaire,?Pittsburgh Sleep Inventory, etc.) and a clinical exam that does not indicate a sleep disordered breathing problem, then it likely does not exist!

Based on the number of sleep courses being offered to general dentists one would think that half the world and all jaw pain and bruxism patients have airway problems. This is certainly not the case!

For curiosity sake over the years I have sent patients with very aggressive sleep bruxism, but no historical screening or clinical evidence of sleep disordered breathing, for overnight sleep studies either in the lab or with home sleep testing devices. I don’t recall a single patient being diagnosed with airway compromise. This is NOT surprising because the best research to date suggests that at most there is an?association?between sleep bruxism and airway compromise. But a causal linear relationship just doesn’t exist. Beyond this effort, pulse oximetry recordings on patients with maxillary flat plane appliances do not reveal an increase in oxygen desaturation events.

For these reasons I feel strongly that the TMD-Bruxism-Sleep-Disordered Breathing triad has been grossly overblown as a direct result of continuing education programs desperately trying to sell their courses based upon potential revenue streams. With the promise that inserting mandibular advancement devices will not only CURE your bruxism patient but bring in revenue as well one can understand the excitement.

Some commentary now on flat plane versus anterior contact appliances:

The term deprogrammer has been assigned to these anterior contact devices but I have never understood what they deprogram. When used during the day as some advocate, I suspect that they can assist efforts to change acquired daytime behaviors that bring the teeth together. So when being worn the patient shouldn’t purposely bite on it but instead lower tooth contact on the device should serve as a reminder to keep the teeth apart. The end result would be less muscle contraction, less muscle fatigue and likely less pain. The patient will hopefully no longer be making a fist in his or her face during the day. Nothing has been?reprogrammed?but nature now has a chance to influence healing.

At night do these deprogrammers rule the day? Since these appliances separate the back teeth during bruxism and seemingly lead to transient reductions in masseter and temporalis contraction, is this an advantage? For some patients this strategy has worked well at least for a short period to time. Continued use, however, is risky, as forces don’t just disappear. Whatever forces were removed from the masseter and temporalis muscles now find their way to the TM joints. As a result, stable joints may become unstable and unstable joints may just get crankier.

In addition, the use of deprogrammers at night over several months can lead to bite changes. Not uncommonly these devices prompt the emergence of an anterior open bite particularly in high-angle cases or when third molars are present. Nightly wear of these devices without supervision can be a problem.

So, if you are compelled to use anterior deprogrammer devices because of patient unresponsiveness or worsening of symptoms with full coverage devices, proceed with caution. Tell your patients what could happen and limit the use to three to four nights per week. On the other nights return to a full-coverage device and pay great attention to freeway space and create an occlusal scheme where there are only five contacts (first molars, cuspids, and one anterior stop). No one ever said you could only prescribe one appliance!

My take-home message: Careful listening and looking along with a broad-minded treatment approach is still the most predictable way to proceed.

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