docTMJ Disorders & Imaging Techniques
When it comes to diagnosing TMJ disorders, X-rays and other imaging techniques provide invaluable information. They provide a window to the underlying structures and the inner workings of the jaw joints. But how do we decide what X-rays or imaging techniques to use? And the answer depends on what it is exactly that we are searching for. Let’s review the most common imaging and X-ray techniques used today in diagnosing TMJ disorders.
Common Imaging & X-rays
Let’s begin by reviewing the major categories and then we’ll dive into each in further detail.
- X-rays
Everyone has heard the term “X-ray.” We hear it when we go to a doctor or visit the dentist. This is one of the most commonly used technologies in any dental or medical practice. X-rays show hard bony structures very well. So when it comes to looking at bone and teeth, they are great.
- Cone Beam Computer Tomography (CBCT)
Advances in computer technology combined with X-rays have allowed for a more detailed look at hard tissue structures like bones and teeth. What separates this from conventional X-rays is the level of detail visible. This is done by “digital slicing” of the TMJ at different angles to get a 3-D image.
- Magnetic Resonance Imaging (MRI)
Magnetic Resonance Imaging is by far one of the most advanced ways of visualizing the jaw joints. The way the images are obtained is fundamentally different than for X-Rays or CBCT. MRI’s are used for a detailed look at the “soft tissue” structures, like muscles and joints. They are great for seeing what cannot be seen on X-rays, the soft tissue.
Now that we have the top 3 groups, let’s look at each in more detail.
X-Rays
When it comes to diagnosing problems with the TMJ, X-rays are always the first step. They are relatively quick and considerably more affordable than the other options. Plus, most dentists have this piece of technology available in the office. There are certain types of X-rays that are particularly helpful for TMJ.
Panoramic X-ray
This shows a broad and overall view of the patient’s teeth, jaw bones, sinuses, and other facial bones and structures. It is a perfect screening tool because it provides an overall view of the head and neck region. The amount of radiation is minimal and completely safe. It is also more economical than other imaging options. While it is great for showing moderate to major tissue changes, The major drawbacks are the lack of detail and the overlap of adjacent structures.
Lateral TMJ X-rays
TMJ X-rays are a more lateral view of each jaw joint. These X-rays capture the major bony structures involved in the opening and closing of the jaws. Much like panoramic X-rays, they are safe and economical. They provide a great way to visualize the jaw bone-to-skull relationship in closed-mouth and open-mouth positions. There is more detail and sharpness to the image. Also, we don’t have as much overlap as we do with a panoramic X-ray.
Cone Beam Computer Tomography (CBCT)
CBCT uses “Cone Beam” X-ray technology to angle and target the X-ray photons to the jaw joints. These images are then captured and using “computer tomography” converted to visual slices of the TMJ in different planes. These images are then assembled together to form a 3-D hard tissue X-ray. Visualize a sliced loaf of bread. If you want the middle slice, you can just remove it away from the rest. The CBCT shows X-rays of digital slices in different planes (front-to-back, side-to-side, down-to-up). The doctor can visualize these digital slices for a better understanding of the disease state.
Furthermore, with the aid of computer technology, a 3-D image of the joint can be obtained. This has tremendous benefit in further detailing what is happening to the patient’s jaw bones and jaw joints.
Magnetic Resonance Imaging (MRI)
MRI is a completely different piece of tech than X-rays. With X-rays, photons are emitted from the X-ray source. These photons then travel thru the patient and are then captured on the X-ray sensor. Magnetic Resonance Imaging doesn’t depend on photons to see. MRI is based on the premise that all living organisms contain positive and negatively charged ions. Strong magnets are used to generate a magnetic field across the body which causes the ions in the tissues of the body to line up a certain way. Another magnet is then used to pull the ions out of their alignment very briefly. When the ions return to their previously aligned state, they release a certain amount of energy. Sensors are used to record these changes in energy levels and eventually produce an image of the tissues and organs being viewed.
MRIs produce detailed 3-D images of “soft tissue” organs. Muscles, tendons, ligaments, joints, blood vessels, and nerves are all soft tissue organs and structures that can be viewed with an MRI. Tumors, internal bleeding, and tissue changes are readily visible As useful as they are in medicine, MRI machines are extremely expensive and costly to maintain. They weigh a ton (literally they weigh 4-7 tons). They have to be kept quite cool as they generate a tremendous amount of heat. And since they are “magnet” driven, the patient must remove all soft tissue metallic body piercings beforehand.
Best TMJ Imaging
More often than not a panoramic view and TMJ lateral X-rays provide a detailed view of the jaw bones and what the TMJ looks like (in the sense of its bony components). A CBCT is very useful when it comes to further evaluating for bony structural changes and damage. The level of clarity reveals bony changes that are not visible on traditional X-rays. MRIs are mainly used to visualize the soft tissue in the TMJ. If the disc or the supporting ligaments, connective tissue, and muscles are to be looked at and evaluated, then MRI is the solution.
The best imaging technique is a “patient-driven” technique. Meaning that we utilize the imaging best suited for the evaluation of the condition at hand. Traditional X-rays like a panoramic are first used as a screening tool. Then the patient’s symptoms and the findings on the panoramic will indicate if and what type of further imaging is necessary.
Dr. Eslampour has over 15 years of experience treating TMJ disorders. If you have problems with chewing, jaw pain, or other joint-related issues, our doctor can help you too. Call us now.