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Start With the Joint

A patient’s guide to the temporomandibular joint

Mark A. Piper, DMD, MD · Oral and Maxillofacial Surgeon

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A note from Dr. Piper

For forty years my practice was devoted to the patients whose problems had not been explained, and to those whose treatment had not worked. I operated on the most damaged joints under the operating microscope, but I was more than a surgeon. I consulted on orthodontic treatment without surgery for growing children, and on restorative dentistry, such as crowns, for adults. After diagnosing the condition of the joint, I determined whether bite surgery or airway treatment was safe. I treated pain arising from the TM joint, the neck, the brain and spinal cord, and the nerves of the face and neck, including the sympathetic nerves.

No matter how complicated the patient, every evaluation began in the same place: a thorough examination of the bite and skeleton, the exact condition of the joint structures, and a diagnosis of the source of the pain. My practice differed from most because I obtained imaging before treatment. Every recommendation I made was based on CT scans of the head and upper neck, and on MR imaging of the joint structures, bite, skull base and deep face, and, where indicated, the neck and brain.

In most of these patients, the problem began in the jaw joint itself. The bite, the shape of the face, the airway, and the pain followed from what had happened inside the joint. The teeth were often the first place the problem showed itself. The patients most often missed were children being evaluated for braces because of a short lower jaw.

In children and adults alike, pain usually appeared long after the joints were damaged. That is why treating the pain alone allowed the damage to the joint to worsen. Ironically, most patients do not seek help until they hurt. For many of them, braces, crowns, bite surgery, splints and airway appliances could not correct the damage in the joint foundation. The delay in surgical treatment often meant that the disc had to be removed rather than repaired, that the joint had to be replaced with an artificial one rather than preserved, and that the bite and airway had to be corrected with surgery rather than the skeleton being saved from degeneration.

This guide is the explanation I gave my own patients, in plain language. It will show you how the joint works, how joint damage is staged, the signs that your joint may be involved, and the questions worth asking before any expensive or irreversible treatment begins.

I am not here to tell anyone their treatment was wrong. I am here to provide an anatomical baseline and explain the advantages of looking at the foundation first, from which every treatment philosophy can draw to ensure its best success.

How to use this guide

Read it once, then keep it. Bring it to your dentist, orthodontist, physician or surgeon. The checklist of signs in Part Three and the ten questions in Part Five are written to be used in the examination room.

This guide is educational. It does not diagnose your condition, does not create a doctor and patient relationship, and does not replace an examination by your own clinician.

Part One: How the TM joint works

You have two jaw joints, one just in front of each ear. Their medical name is the temporomandibular joint, often shortened to TMJ. Each joint is a hinge that also slides. When you open wide, the ball of the jaw rotates and then glides forward.

The disc

Between the ball of the jaw and its socket sits a small cushion called the disc, much like the discs in your spine. Ligaments on the outer and inner sides of the joint hold the disc in place on top of the ball.

When the ligaments stretch or tear

An injury, a fall, a car accident, or years of strain can stretch or tear those ligaments. The disc may then slip forward and out of place. Bone presses on the soft tissue behind the disc, which carries the blood supply to the joint. The joint begins to change.

What follows when the joint changes

A damaged joint rarely stays a joint problem alone. Because the teeth, the jaw and the face all rest on the joint, a change in the joint may show itself somewhere else entirely.

Noise and movement. Clicking or popping usually means the disc is slipping off the ball and back on again. When clicking stops and the jaw no longer opens fully, the disc may have locked out of place. Grating or crunching sounds may mean bone is rubbing on bone because the tissues have worn through.

The bite. When a joint loses height, that side of the jaw becomes shorter. The teeth follow the jaw. The bite can drift, and it can keep drifting no matter how carefully the teeth are adjusted, because the foundation beneath them is still changing. I call this Joint Based Malocclusion: when a damaged joint keeps changing, the joint causes the bite to drift.

The face. In an imaging study of 100 patients whose faces and bites had changed, my colleagues and I found that degeneration of the jaw joint was the leading cause, and that the chin moves toward the side of the smaller, more damaged joint.¹

Children. Children injure their jaw joints in falls and sports far more often than anyone realizes. A joint injured in childhood can change how that side of the jaw grows. The result may be a small chin, a crowded bite, or a face that grows unevenly.^2,3,4

The airway. A jaw that has not grown fully, or that has lost height later in life, sits further back. The space you breathe through can narrow with it.

Pain. Joint damage can produce pain in the joint, the face, the head, the neck, and the ear. Pain usually starts long after the joint has been injured, or after the damage has progressed. The term “TMJ” is often used to mean pain, but not every source of facial pain comes from the joint, which is exactly why the joint, the neck, and the nerves all need to be examined. Some “TMJ” patients are found to have perfect joints with no damage on imaging. It is equally important to know when a joint is normal, so that unnecessary treatment can be avoided.

Part Two: The Piper Classification, in plain language

Over decades of surgery and imaging I developed a way to describe how far a jaw joint has deteriorated. This is the Piper Classification, and it runs from Stage 1, a normal joint, to Stage 5B.⁵ The stage is read from MR and CT imaging. Symptoms alone cannot tell you the stage, but they often give clues.

Why the stage matters to you

The stage of a joint is not a verdict. It is a map. It tells you and your clinician what the joint has become, and what it may become.

Silence is not always good news. Many patients are relieved when a click goes away. Sometimes that means the joint has settled. Sometimes it means the disc has locked out of place, which is a step further along, not a return to normal. Only imaging can tell the difference.

The inner side matters most. When the disc slips toward the inner side of the joint, it presses on the area through which most of the blood reaches the bone of the jaw joint. That is why Stages 4A and 4B deserve close attention, particularly in a growing child, where the joint may not grow fully, and in an adult, where the bone may lose its blood supply.^5,6

A changing joint means a changing bite. If the joint is still changing, a bite that is perfect today may not be perfect next year. That does not mean treatment should not happen. It means the plan should account for the joint, and you should be told the realistic risk before you agree to it.

The principle I practiced by: know the condition of the joint before you build on it. A house is only as stable as its foundation, and the jaw joint is the foundation of the bite, the jaw and the face.

Part Three: Signs that the joint may be involved

Check any that apply to you or your child, and bring this list to your appointment. None of these signs proves that the joint is the cause. Each is a reason to ask whether the joint has been examined. If several apply, the question becomes more important.

• Your jaw clicks, pops or grates when you open or chew.
• Your jaw has locked, caught, or no longer opens as wide as it used to.
• A click you had for years suddenly stopped, or suddenly became painful.
• Your bite feels different than it did a year ago, or the back teeth hit first.
• Your front teeth no longer meet.
• Your chin has drifted to one side, or your face looks less even than before.
• Your symptoms began after a car accident, a fall, a sports injury, or a long dental appointment.
• You have pain in front of the ear, in the face, the temples, the neck or the ear itself.
• You have seen more than one dentist or physician, and each gave a different explanation.
• You were told the pain is stress, or that nothing shows on an X ray.
• Your child has needed braces more than once, or has a small chin, or has been told they need airway treatment.
• Your bite keeps changing after it has been adjusted, or after orthodontic treatment ended.

Part Four: When a scan of the joint may be worth asking about

A standard dental X ray shows the teeth and the bone around them. A panoramic X ray, often called a Panorex, shows the upper and lower jaw bones, but only gross changes in the joint appear on it. Neither shows the disc or the other soft tissues.

MRI shows the disc. CT shows the bone.

To see the whole joint, two kinds of imaging work together. MR imaging shows where the disc sits, the condition of the soft tissue, and swelling within the bone. CT shows the shape and size of the bone. Together, they show the present condition of the joint and what may happen in the future.

The joint should be imaged in more than one position

This applies to the MRI. A disc may sit in place in one jaw position and slip out in another. For that reason, I recommend imaging the joint with the jaw in four recorded positions: fully seated (FSCP), with the front teeth edge to edge (IEP), biting together normally (MIP), and opened wide (TCP). Your dentist should know how to record these positions for your MRI. Ask whether the imaging you are offered includes more than a single closed position.⁵

CT scans do not show the disc or the other soft tissues, and each CT involves a small amount of radiation. The CT captures the posture of the condyle, the ball of the jaw, along with the bite, the profile, and the airway. I recommend that your dentist record the fully seated position (FSCP) for the CT. The scan will then show the full distortion of the bony structures that has resulted directly from your joint damage. The FSCP images of the MRI can be compared with the CT in that same recorded position, showing what the soft tissues are doing with the bone in that posture.

Situations where imaging may be worth discussing

• Before orthodontic treatment in a child or adult with any of the signs listed in Part Three.
• Before extensive bite reconstruction, crowns across many teeth, or bite adjustment.
• Before corrective bite or airway surgery. In a study of 100 jaw surgery candidates, every patient whose bite was changing had joint damage.⁷
• After an injury to the face, jaw or neck, particularly if symptoms began weeks later.
• When the chin has drifted, or the face has become uneven.
• When pain has not been explained, or treatment has not worked.

Part Five: Ten questions to ask before treatment begins

Every treatment philosophy publishes its successes. Your protection lies in understanding the realistic risk of failure before you consent, and that begins with the condition of the joint.

1. Has the condition of my jaw joints been examined, and how?
2. Would MR or CT imaging of my joints change the plan you are recommending?
3. If my joints are imaged, will it be done in more than one jaw position?
4. What stage are my joints, and are they stable or still changing?
5. Where will my jaw joint be positioned when my bite is built, and why that position?
6. If my joint keeps changing after treatment, what happens to my bite?
7. Which parts of this treatment can be undone, and which cannot?
8. What happens to patients for whom this treatment does not work?
9. Is there a way to protect the joint before, or while, my teeth are treated?
10. Would a second opinion from someone who images the joint be reasonable before I begin?

Your next steps

• Bring this guide, with the checklist completed, to your next appointment.
• If your symptoms began after an injury, record what happened with the free jaw injury record at pipereducation.org/trauma.
• See which stage your symptoms may suggest with the Piper staging tool at pipereducation.org/resources.
• Read more in the patient library at pipereducation.org/library, and find the free eBooks at pipereducation.org/ebooks.

Both patients and dentists are welcome. Follow along. I have much more to share.

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Your pain is real. It is in your head, just not made up in your brain.

References

Educational content only. This guide does not diagnose any condition, does not create a doctor and patient relationship, and does not replace an examination by your own clinician. © 2026 Mark A. Piper, DMD, MD. Piper Education, pipereducation.org