Occlusal Appliances Ebook

OCCLUSAL APPLIANCES

The Options

By Frank Spear, D.D.S., M.S.D.

CONTENTS

OCCLUSAL APPLIANCES 4 8 10 12 14 16 18

The Options

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The Options Why use them? Part 1 Why use them? Part 2 How do they impact muscles? Part 1 How do they impact muscles? Part 2 How do they impact joints?

Diagnosing Muscle and Joint Pain The Anterior Only Appliance for treating muscle pain: Part 1 SPEAR | OCCLUSAL APPLIANCES: THE OPTIONS

The Anterior Only Appliance for treating muscle pain: Part 2

Occlusal Appliances THE OPTIONS

By Frank Spear, D.D.S., M.S.D.

As an educator, one of the most confusing areas for clinicians, in my experience, concerns which occlusal appliance to prescribe. There are many reasons for confusion, not the least of which is that there are a variety of different appliances available and taught by dental schools and private institutions.

Most dentists, therefore, assume that what they are taught must be the correct appliance to use. The confusion starts when they discover someone else uses a different appliance, or the one they use did not fulfill its intended purpose.

This brings us to one of the other reasons significant confusion exists, different patients may respond very differently to the same appliance. This means that your favorite design might be very comfortable for one patient, and yet not tolerated by another. This is especially true if you are trying to manage a patient in pain.

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In this article, the first in a series of articles on occlusal appliances, I will discuss the most common options for occlusal appliances. The appliances I present here would be considered relatively common options. I am aware there may always be other choices, but not widely prescribed.

Figure 1

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Anterior Only Appliances: This family of appliances is characterized by having no posterior occlusal contacts on the appliance; all the occlusion is on the anterior teeth, both in clenching and excursive movements. Familiar names would be a Hawley bite plane, very popular in the 1970s, a Sved appliance, NTI, Best-Bite Discluder and numerous spinoffs named after clinicians.

The differences with these appliances are typically how many anterior teeth are in occlusion and whether the appliance covers the incisal edges of the anterior teeth or not. In addition, these appliances can be constructed on the maxillary of mandibular teeth. Figure 1 represents one style of an anterior only appliance.

Figure 2

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Figure 3

Full coverage appliances built in a seated

patient is moving toward, (group function).

condylar position (centric relation), with

Figure 3 illustrates the concept of a flat

anterior guidance: These appliances may

plane appliance without a ramp.

be made on the maxilla or mandible. In either case, the intercuspal position on the appliance has been adjusted with the

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Full coverage appliances not built in a seated condylar position, but with

patient’s condyles in a seated position. In

anterior guidance: This appliance is also

addition, the appliance has been adjusted so

identical, except its intercuspal position is

that during excursive movements there are

not adjusted to coincide with the patient’s

no posterior occlusal contacts.

seated condylar position. It does provide anterior guidance when the patient moves

Typically, only the canines touch in left and

in a lateral or protrusive direction from the

right lateral movements, and the incisors

intercuspal position.

in protrusive movements. Adding a ramp to the anterior portion of the appliance commonly creates the anterior guidance.

Figure 2 illustrates the concept of a ramp for anterior guidance.

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Full coverage appliances not built in a seated condylar position, flat plane: This appliance is identical to #3, except that its intercuspal position is not adjusted

Full coverage appliances built in a seated condylar position (centric relation), flat plane: This appliance is essentially identical to the #2 appliance mentioned above and can also be made on the maxillary or mandibular arch, the difference is its lack of anterior guidance. Instead, the appliance is built as a flat plane, this typically allows some posterior occlusal contacts during excursive movements, particularly on the side the

to coincide with the patient’s seated condylar position. And as in #3, it typically allows for posterior occlusal contacts in excursive movements.

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Posterior only appliances: These appliances are the opposite of anterior only appliances, in that they have only posterior occlusal contacts, no anterior contacts. Common names would be a Gelb appliance or a Posterior Pivot. Figure 4 represents an example of a posterior only appliance without anterior contact.

Figure 4

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Mandibular anterior repositioning appliances: These appliances direct the mandible to a specific position anterior to a fully seated joint position. Depending upon the design of the appliance, they typically allow some amount of movement in a protrusive or lateral direction from the directed position.

In addition, they commonly cover both the maxillary and mandibular arches, but not always. The common appliances in this

Figure 5

category are used to treat snoring or sleep apnea. Figure 5 represents a maxillary only appliance designed to direct the mandible into an anterior position.

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Soft appliances: These appliances are typically full coverage and created on either the maxillary or mandibular arch. Their occlusion varies as they are compressible and therefore the occlusal contacts change with bite force. They may be thought of as the common pressure formed athletic mouthguard but can be used for other purposes as well.

These eight categories cover the most common appliance designs, there is no wonder confusion exists given the number of possible options.

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Different patients may respond very differently to the same appliance.

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Occlusal Appliances: Why Use Them?

PA R T 1

By Frank Spear, D.D.S., M.S.D.

Figure 1

In the previous article in this series I outlined the more common occlusal appliance options available. In this article, I’ll provide an overview of the more common reasons for prescribing occlusal appliances. In future articles I will describe which of the appliances may be most appropriate for each of the conditions this article mentions.

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Diagnosing the etiology of pain: It is not uncommon for a patient to come in complaining of head and neck pain. However, the location and the severity of the pain can vary dramatically from patient to patient.

In addition, the etiology of the pain may be related to muscle issues, temporomandibular joint issues or a multitude of other causes.

Appliances can be very helpful in diagnosing whether alterations in the occlusion will have

Fundamentally, all clinicians need to realize that there must be a reason for prescribing and fabricating an occlusal appliance. It is, in fact, the reason you are prescribing the appliance that informs you of which appliance may be most effective.

any effect on the pain, but they can also be extremely useful in helping to differentiate muscle pain from TMJ pain. The key is to use an appliance that will provide that information, as many will not.

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Treating pain that is muscle, not TMJ based: For most patients who present with head and neck pain, muscles are the source of the pain. There can however be significant differences in the effectiveness of different appliances at resolving muscle pain. Once the diagnosis is made that muscles are the source of the problem, it is possible to outline which appliances may be the best choices.

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Treating pain that is TMJ based during excursions: The challenge of pain that originates in the jaw joints is determining where the condyle is when the pain occurs.

The pain may occur when the condyle goes to a seated position, but more commonly occurs during excursive movements, such as chewing gum or tough meats.

The first component of determining which appliance to use is to diagnose whether the pain is of TMJ origin as opposed to muscle origin. If it is joint based, the next diagnosis to make is whether the pain occurs on the side the mandible is moving towards during chewing, the side it is moving away from, or both. Those findings will then aid in choosing the appliance that potentially can reduce the pain.

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Treating pain that is TMJ based during condylar seating: There are patients whose pain is joint based, not during mandibular movement, but when the condyle seats in the fossa. These patients may also have excursive pain as well. If not correctly diagnosed, many appliances may make this patient worse, so the diagnosis and appliance selection is critical.

Evaluating occlusal changes prior to restoration or equilibration: Many times dentists and patients want to know if occlusal correction will be successful at eliminating symptoms without the need to ultimately wear an appliance. In these instances, appliances that mimic what can be achieved on teeth can be used to test the outcome.

Truthfully, no occlusal appliance is completely capable of simulating the identical outcome that will occur on the natural teeth.

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Occlusal Appliances: Why Use Them?

PA R T 2

By Frank Spear, D.D.S., M.S.D.

The following is a continuation of the overview of the more common reasons for prescribing occlusal appliances. In Part I, I discussed: • Diagnosing the etiology of pain • Treating pain that is muscle, and not TMJ based • Treating pain that is TMJ based during excursions • Treating pain that is TMJ based during condylar seating • Evaluating occlusal changes prior to restoration or equilibration

Figure 1

Here are three more common reasons: 1

Dentistry has become much

Diagnosing the level of a patient’s parafunction following occlusal changes: Many patients present with significant tooth

more attuned to the prevalence

wear from parafunction due to multiple

of sleep-related breathing

etiologies. It is possible to use an appliance

disorders and the opportunity

as a way of assessing the patient’s current parafunctional activity level. This information

for some occlusal appliances

can help in predicting a prognosis for

to have significant benefits in

restorative treatment, but also in making

their treatment.

patients aware of the level of parafunction present. This can also aid in determining if investigations into the etiology

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of the parafunction, such as sleep studies, is appropriate.

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Treating snoring or sleep apnea:

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Protecting teeth or restorations from wear or fracture:

to the prevalence of sleep-related breathing

Many times, the reason for prescribing

disorders and the opportunity for some

an appliance is simply to protect teeth or

occlusal appliances to have significant

restorations from wear or fracture; any

benefits in their treatment. Unfortunately,

occlusal appliance does that, but some are

other appliances may make the breathing

much more easily fabricated, adjusted and

disorder worse, so the appliance choice

worn than others. Additionally, sometimes

is critical.

they may need to be worn at times during the day, as well as at night. This will affect which appliances may be more appropriate.

Learn More about Demystifying Occlusion

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Dentistry has become much more attuned

Occlusal Appliances: How do They Impact Muscles?

PA R T 1

By Frank Spear, D.D.S., M.S.D.

In this series, I have previously described the common appliance options available as well as the reasons an appliance may be prescribed. I’ll now describe how the different appliances may impact muscle activity levels.

It is critical that clinicians realize one of the great challenges of occlusion, and particularly appliance therapy is that different patients may respond differently to the same appliance. For example, many patients will reduce their clenching and grinding activity when prescribed an anterior only appliance, but others may increase their clenching activity. It is for this reason that we can’t say absolutely what any appliance will do since it is very patient dependent.

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It is important to understand that if we are talking about pain management, often the patient gets better regardless of which appliance is used. In fact, Laskin and Greene in the 1970s provided patients in pain with mock appliances, which didn’t alter the occlusion in any way and a significant percentage of patients saw improvement.

They also did mock equilibrations, where they used a smooth bur, so nothing actually got adjusted and a significant percentage of patients reported relief.

Figure 1

RESEARCH FOR DIFFERENT APPLIANCE DESIGNS AND MUSCLE ACTIVITY LEVELS Different occlusal appliances and their impact on muscle activity have been investigated for decades. This research is typically done by placing surface electrodes over the masseter and temporalis muscles. Some studies include the digastrics, trapezius and sternocleidomastoid muscles as well.

The patient is asked to clench and move while the electrodes record the electrical activity from the different muscles. This may first be done on the natural teeth to get a baseline level and then an appliance is inserted, and the recording process is repeated. In most studies the appliance is then altered to provide a different occlusal scheme and the process is repeated.

THE RISK OF INTERPRETING THE RESEARCH DATA The research performed as I described is the

There are patients who experience significant

basis for many of our beliefs about how different

relief of muscle symptoms from an appliance and

appliances effect muscles, but it is important

a few months later, no longer get relief from the

to realize there are risks in utilizing the data as

same appliance but do from a different design.

gospel for all patients. For one thing, the patients

And finally, research done on 10-20 patients

in these studies are all awake and conscious of

doesn’t mean everyone will behave the same

what they are doing during the process. Second,

following the same treatment.

it is a temporary and artificial change to their occlusion; this doesn’t mean the changes in muscle activity levels seen with different occlusal designs would continue over a long time period.

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Occlusal Appliances: How do They Impact Muscles?

PA R T 2

By Frank Spear, D.D.S., M.S.D.

As I mentioned in the Part I of this series, it is critical that clinicians realize that different patients may respond differently to the same occlusal appliance. I discussed the research around different appliance designs and the risks with interpreting the data. The following is further investigation into how appliances impact muscles.

WHAT THE RESEARCH SAYS: Despite my earlier remarks in Part I, I wouldn’t discount the research findings as invalid, just not completely reliable for all patients. With that in mind, here are the fundamental findings of how different occlusal appliances influence muscle activity levels.

It is helpful to separate the muscle activity levels into those generated during clenching, as opposed to those generated during excursive movements of the mandible.

CLENCHING: Most research comes to the same conclusions regarding clenching muscle activity levels. Any full coverage or posterior only appliance has the potential to increase total conscious clenching muscle activity levels above what is possible when the patient clenches on their own teeth.

There is a significant reduction in conscious clenching muscle activity levels when an anterior only appliance is placed. In other words, clenching muscle activity levels are reduced when there is no posterior occlusal contact.

Research finds the clenching activity level is affected by how many teeth are touching on an anterior only appliance. For example, there is a reduction of activity levels if an anterior only appliance is used over a full coverage appliance, but even further reduction if the anterior appliance has only the centrals touching as opposed to six anterior teeth. There are potential dangers in reducing the number of teeth touching; however, as there is a significant risk to the teeth actually in contact if the patient continues to clench at a high level, which does happen in some patients.

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EXCURSIONS: The role of posterior occlusal contacts appears to impact excursive muscle activity levels the same as it does in clenching. Appliances that have posterior contact when the mandible is moving have a greater level of muscle activity than those that don’t. The ones that don’t are anterior only appliances, which have no posterior contact when clenching or during movement and full coverage appliances with anterior guidance, which don’t reduce clenching activity but do reduce excursive muscle activity when the posterior teeth separate during excursions.

Any appliance that has posterior contacts during excursions have the potential for a greater level of muscle activity than those that do not.

LATERAL PTERYGOID ACTIVITY:

CONCLUSION:

The bulk of appliance research leaves out the

The bulk of the evidence from research suggests

lateral pterygoid muscle because of the fact that

that if the patient only has muscle pain, anterior

it requires a needle electrode be inserted in the

only appliances, or full coverage appliances

muscle to be able to research it. While research

adjusted to a fully seated joint position with

has been done using needle electrodes in both

anterior guidance would have the greatest chance

the superior and inferior belly of the lateral

for success. But as I said earlier, this doesn’t mean

pterygoid muscles, I am not aware of any which

they are the only ones that will be successful, or

specifically looked at different appliance designs

that they will always be successful.

and their impact on either head of the muscle.

Clinical evidence suggests that the key occlusal element that allows for a reduction in lateral

that different patients may

the condyle to seat completely; anterior only

respond differently to the same

appliances and full coverage appliances that

occlusal appliance.

are adjusted to a fully seated joint position fit this requirement.

Learn More about Managing Compromised Occlusions

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pterygoid activity is for the appliance to allow

It is critical that clinicians realize

Occlusal Appliances: How Do They Impact Joints?

By Frank Spear, D.D.S., M.S.D.

WHERE DOES JOINT PAIN COME FROM? Pain in the area surrounding the TMJ can be referred from several sources, particularly muscles.

This is especially true of pain in front of the ear, over the joint. If the joint is asymptomatic, the appliance choice will be directed at solving the muscle problem. However, there are many patients who present with pain occurring from the joints.

The most common source of that pain is an internal derangement of the joint where the intra-articular disc is displaced in an anterior direction. The disc normally sits between the condyle and fossa; when the condyle compresses it under load, the disc is not innervated and

In a recent article I described how occlusal appliances potentially impact muscle activity levels; in this article I will carry on that thought process to show how they impact the TMJs. It is important to recognize that the conclusions from the last article and this article are intimately linked. If an appliance significantly reduces muscle activity levels, it will also significantly reduce the load on the TMJ.

discomfort does not exist. The back of the disc

Figure 1

Figure 2

is attached to the head of the condyle by the ligamentous attachment and prevents the disc from being displaced, but if the ligament is torn or stretched the disc may displace.

In addition, the posterior of the disc is attached to the back of the fossa through the highly innervated and vascular retrodiscal tissue. When a disc is displaced anteriorly this tissue is now moved across the head of the condyle and could possibly be compressed under joint load.

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WHEN DOES IT HURT? In reality, disc displacement is fairly common, with

However, research says that the biggest factor

research stating it may occur in one out of three

in reducing joint loading is to provide posterior

adults. The majority of patients do not experience

occlusal contacts. Even though the muscle

pain, but in some patients, it can be very painful.

activity levels may not be as low, the posterior

The critical part of choosing an appliance design

occlusal contacts absorb most of the force of the

is to identify if the joint hurts when the condyle is

muscle contraction which reduces the load on

going to a seated position, or if it hurts when the

the joints. It is estimated that with anterior-only

mandible is moving.

contact, 60 percent of the force from muscle contraction goes to load the joints; by adding

Understanding joint anatomy helps in

occlusion back to the second molars, only 5

understanding the pain. The disc appears clearly

percent of the force of the muscle contraction

in most two-dimensional diagrams of the joint,

reaches the joint.

but has significant width in a medio-lateral dimension that extends completely across the head of the condyle. When discs displace, it is common for only a portion of the disc to displace anteriorly, leaving the rest of the disc in the correct position.

This explains why it is possible to have a displaced disc but no pain when the mandible is in one position but hurts in another. In addition, we know that most discs reduce as the condyle moves back onto the displaced disc during movement and when the condyle is back on the disc, no discomfort occurs.

WHAT APPLIANCES TO USE? Since posterior occlusal contacts significantly reduce joint loading, the appliances that tend to be most effective all have posterior occlusion.

This means posterior-only appliances work as well as full coverage appliances. Again, the key is to know when the joints experience pain.

If the joint hurts when the condyles are going into a seated position, the appliance will need to provide posterior occlusion and be adjusted to provide an intercuspal occlusion with the mandible in an anterior or protruded position.

HOW DO OCCLUSAL APPLIANCES AFFECT JOINT LOADING?

If the joint hurts with the mandible moving, the

Choosing the correct appliance for a patient

when the mandible moves to the painful location.

with joint pain requires an understanding of

This often means removing any anterior guidance

how appliances may impact joint loading, and

from the appliance if the pain is in the joint on

therefore, joint pain. The first possibility is to use

the same side the mandible is moving towards. If

an appliance that attempts to reduce overall

the joint on the side the mandible is moving away

muscle activity levels, such as an anterior-only

from experiences pain, it may be necessary to

appliance or full coverage appliance with anterior

create non-working contacts in the occlusion of

guidance, to reduce pain.

the appliance to support the joint.

appliance will need to provide posterior occlusion SPEAR | OCCLUSAL APPLIANCES: THE OPTIONS

Occlusal Appliances: Diagnosing Muscle and Joint Pain

By Frank Spear, D.D.S., M.S.D.

In this series I have discussed what appliance options exist, why we typically use occlusal appliances and the potential theory of how they impact muscles or joints, recognizing that not all patients respond to appliances the same way. This article describes what appliances I personally would use for different purposes, starting with diagnosing the etiology of facial pain.

WHAT IS CAUSING THE PAIN? Pain is a particularly confusing entity for clinicians because of the sheer number of possible etiologies. The pain could be from muscle, joint, or other, with other being a huge category. As a clinician, I want to know whether

For most patients an anterior only

the pain could be reduced with an occlusal appliance or not.

appliance has a significant impact at reducing muscle activity levels.

Every patient with facial pain needs to know in advance that three things could occur following wearing a diagnostic appliance: they get better, they stay the same, or the appliance makes them worse. All three answers are helpful in making

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a diagnosis as to the etiology of the pain and in determining what appliance may ultimately be fabricated for the management of their pain.

HOW TO FIND OUT? One of the challenges with appliance therapy is

The reason I use the bite plane is because of

how to charge for it. If you make models, send

the minimal time and expense to make it, and

them to the lab, pay for the appliance, take the

its a near perfect appliance to aid in diagnosing

time to adjust it, and then discover the patient

muscle versus joint issues. For most patients an

doesn’t improve, the patient is frustrated and so

anterior only appliance has a significant impact at

are you. My preference is to explain to patients in

reducing muscle activity levels. For most patients

pain that I want to make a diagnostic appliance as

with muscle only pain, they experience significant

a tool to attempt to identify the cause of the pain

pain relief in a day, or certainly less than a week. If

prior to fabricating and adjusting an expensive

the bite plane resolves the pain, it’s probably their

appliance only to find out it may not be effective.

long-term appliance of choice for nighttime wear (Figure 2).

The first appliance I use for diagnosis is an For patients with intracapsular joint pain, the

pressure formed thermoplastic baseplate and add

anterior bite plane may increase their level of

composite to it to create the bite plane (Figure 1).

discomfort. It is important to realize that if the

After you have a maxillary or mandibular model

bite plane increases a patient’s pain, it is a useful

the bite plane can be fabricated in roughly 15

diagnostic finding, as it probably indicates some

minutes. I usually make it on the upper arch.

joint involvement.

Figure 1

Figure 2

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anterior bite plane. I make this chairside on a

Because the Aqaulizer has occlusal contacts in the posterior in all but the most extreme mandibular positions, it’s an excellent appliance to test a patient’s response to see if posterior occlusal support can reduce their pain.

WHAT ABOUT A SECOND APPLIANCE? If the bite plane can’t be worn because of pain, the second appliance I use is an Aqualizer from Great Lakes Orthodontics (Figures 3 and 4).

It is a premade posterior only appliance that consists of two fluid filled reservoirs in the posterior, connected by a tube running across the anterior. It is essentially a fully balanced, self-equilibrating appliance with minimal or no anterior tooth contact.

Because the Aqaulizer has occlusal contacts

Figure 3

in the posterior in all but the most extreme mandibular positions, it’s an excellent appliance to test a patient’s response to see if posterior occlusal support can reduce their pain. In my experience if a patient can’t wear an anterior bite plane, but loves an Aqaulizer, they almost always have disc displacement issues within one or both joints. If the Aqaulizer provided significant pain relief, the patient will need a full coverage 20

appliance long term, and it will likely need to provide posterior occlusion in excursions as well as the intercuspal position.

Figure 4

Learn More about Anterior Open Bites

IF NEITHER APPLIANCE HELPED? If neither appliance had any impact on the therapy will not be adequate for their treatment and other etiologies should be considered. At this point you will need to decide if you desire trying additional modalities, such as physical therapy, biofeedback, massage, muscle relaxants or refer them for further diagnosis to someone who manages facial pain on a regular basis.

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patient’s pain, I would be concerned that occlusal

Occlusal Appliances: The Anterior-only Appliance for Treating Muscle Pain PA R T 1

By Frank Spear, D.D.S., M.S.D.

As I described in a previous article, an anterior-only appliance is an excellent choice for patients with muscle pain because it reduces muscle activity levels in clenching and excursions in most patients. However, it does have two risks: developing an anterior open bite from anterior intrusion/posterior eruption and developing an anterior open bite from the mandible repositioning itself into a more retruded position.

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The critical issue regarding anterior intrusion/posterior eruption is the time the appliance is worn each day. I personally tell patients that eight to 10 hours a day is the most I am comfortable with to minimize the risk of developing an anterior open bite. It is possible to make the anterior bite plane on a full arch base plate, and place a pressure formed Essix type appliance on the opposing arch (Figure 1). You’ll be able to safely have the patient wear the appliance more than eight to 10 hours a day, but you do want patients to recognize the risk.

Figure 1

If the patient wants to wear the appliance during the day and at night, a full coverage appliance is a much better choice but may not reduce clenching muscle activity at all, and may even increase it. The full coverage appliance would also need to have anterior guidance and be adjusted in a seated condylar position if you want to reduce muscle activity as much as possible, presuming the patient has no joint issues to preclude using a seated condylar position.

WHAT IF AN OPEN BITE DEVELOPS? If you do have a patient develop an anterior open bite after bite plane wear, make a new set of models and attempt to hand articulate them. If the occlusion fits fine you haven’t had eruption or intrusion, but more likely mandibular repositioning. If the occlusion doesn’t fit, you probably have tooth position changes and removing the appliance will likely result in the open bite closing over time.

Figure 2

Figures 2 and 3 are examples of a patient Photos courtesy of Dr. Harold Menchel.

who wore a small anterior only appliance and had significant changes in tooth position.

These changes are so severe that orthodontic correction will be necessary.

The critical issue regarding anterior intrusion/posterior eruption is the time the appliance is worn each day.

Figure 3

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Figure 4

Figure 5

MANDIBULAR REPOSITIONING? The concept of mandibular repositioning is not

This is why when patients take out their appliance

new, and in fact can be seen even using a full

in the morning, they describe their bite as not

coverage appliance. For most patients their

fitting, assuming the appliance moved their teeth.

habitual position of occlusion, the intercuspal

In reality, what the appliance did was allow a

position, exists with the mandible in a position

release of the lateral pterygoid muscles and the

anterior to the most seated condylar position.

mandible is now in a different position, most often

This means when the condyles do seat, the

retruded to their normal occlusion (Figure 5).

occlusion doesn’t fit; most commonly there

The good news for most patients is that as soon

are contacts only on molars. The response to

as there is recognition the occlusion doesn’t fit;

the posterior only contacts is to contract the

the pterygoids wake up and move the mandible

lateral pterygoid muscles to hold the mandible

back into a normal habitual occlusal relationship

in the anterior position where upon closure the

for them. Unfortunately, this is not true for all

occlusion does fit (Figure 4).

patients, and some stay in a retruded position with an anterior open bite. To my knowledge, no

As soon as any appliance is placed, unless it is

literature has described why the muscles don’t

specifically designed to create an interdigitated

wake up and reposition the mandible, but there

intercuspal position, the mandible can move into

are certain types of occlusion that appear to be

a more retruded position. This is especially true

more at risk.

for an anterior only appliance since there is no posterior occlusion to interfere with condylar seating, but also can happen on a full coverage 24

appliance - especially one that is adjusted weekly into a seated condylar position the first few weeks after it is placed.

You do want patients to recognize the risk.

there is recognition the occlusion doesn’t fit; the pterygoids wake up and move the mandible back into a normal habitual occlusal relationship for them.

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The good news for most patients is that as soon as

Occlusal Appliances: The Anterior-only Appliance for Treating Muscle Pain PA R T 2

By Frank Spear, D.D.S., M.S.D.

As expressed in Part I, an anterior-only appliance is an excellent choice for patients with muscle pain because it reduces muscle activity levels in clenching and excursions in most patients.

WHO IS AT RISK OF MANDIBULAR REPOSITIONING? In my experience two different types of occlusions are at the highest risk for mandibular repositioning.

1

However, it does have two risks: developing an anterior open bite from anterior intrusion/posterior eruption and developing an anterior open bite from the mandible repositioning itself into a more retruded position. This is a continuation of the discussion on repositioning.

Patients with extreme anterior shifts from their seated condylar position to their habitual intercuspal occlusion. I measure this shift on new patients at the initial exam, anytime the anterior shift is 3mm or more, I believe there is a much higher risk for mandibular repositioning.

2

Patients with multiple bites. Anytime you ask a patient to bite and they respond by asking you, which bite do you want, or I don’t know where to bite, you have a very poorly defined intercuspal position and I

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believe a risk of mandibular repositioning with appliance therapy.

WHAT DO YOU DO IF THIS HAPPENS? First, make models and see if they hand articulate well. If they do, but the patient can’t get their occlusion to fit, you have a patient who has experienced mandibular repositioning.

Figures 1 and 2 show a patient who only has occlusal contacts on her second molars, yet her models articulate perfectly except for the deciduous maxillary canine. Her repositioning isn’t from appliance wear, it is from degenerative joint disease that results in the same appearance.

Figure 1

You now effectively have two choices if a patient repositions following appliance therapy.

You can remove the appliance and hope the patient returns to their old occlusion or continue appliance therapy to assure the muscles are relaxed and determine how to close the open bite. Typically, the second option is the best because it will provide a stable mandibular position to create the new intercuspal position.

As to how the open bite is closed, it may be

Figure 2

through posterior equilibration or restorative, orthodontics, often intruding posterior teeth orthognathic surgery.

Having covered the primary risks of using an

An anterior-only appliance reduces

anterior only appliance to manage muscle pain,

muscle activity levels in clenching

I would conclude that anterior bite planes have been the most common appliance I have used for almost 35 years to treat patients with muscle pain, and in that time have experienced less than 10 open bites because of the appliance.

and excursions in most patients.

SPEAR | OCCLUSAL APPLIANCES: THE OPTIONS

using implant anchorage, or potentially

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