Jaw popping or clicking is a condition where an audible noise that can be heard whenever you open and close your jaw. It is a clinical symptom of one of the many TMJ (temporomandibular joint) disorders because a normal functioning TMJ does not have clicking or popping sounds.
To be more precise, these popping and clicking noises fall under the category of internal derangements of the TMJ. Therefore it is a problem with the joint itself and not due to issues with the muscular attachments to the joint.
Table of Contents:
What is internal derangement of the TMJ?
Internal derangement of the TMJ is defined as an abnormal relationship among the components of the TMJ capsule.
The structures within the joint capsule are NOT in their proper position nor alignment with one another.
The result is popping of the jaw upon opening and closing of the mouth.
A study in the Journal of Oralmaxillofacial Surgery has shown that jaw clicking and popping are signs of abnormal joint morphology.
Popping sounds are usually associated with anterior disc displacement.
Crepitation (grinding noises) are associated with arthrosis of the articular surfaces or perforation of the discs.
These findings were consistent with another study, which found reciprocal clicking consistently showed disc displacement with reduction. Their conclusion was that reciprocal clicking can be used as an accurate sign of anterior disc displacement with reduction(ADDWR).
Normal relationship of TMJ components
In a healthy temporomandibular joint, the articular disc is situated in between the mandibular condyle and the mandibular fossa of the temporal bone. The articular disc is essentially sandwiched in between two bones.
The articular disc is made of avascular fibrous connective tissue.
Retrodiscal tissue (RDT). It's attached to the posterior of the disc (bilaminar zone). The RDT is highly vascularized and innervated which is in stark contrast to the disc.
Superior lateral pterygoid muscle tendon. It's attached to the anterior of the disc.
When you open and close your jaw, all of these structures move in unison.
The mandibular condyle first rotates and then translates forward to complete the opening of the jaw.
When the condyle moves, the disc is supposed to stay on top of it and move with it.
The articular disc functions as a stress absorber and as a passive mobile articulating surface for the condyle. When the condyle translates forward, it glides on the disc which is significantly more pleasant than having to glide on bone.
Abnormal relationship of the TMJ capsule structures
When the structures within the TMJ capsule are in disarray, we call it internal derangement. In other words, the structures are out of position and out of alignment with one another in a pathological way.
The most common derangement is anterior disc displacement with reduction.
The articular disc is now located anterior to the condyle instead of on top of it.
When the jaw opens, the condyle has to slide over the posterior part of the disc.
Once the condyle is back on top of the disc, the jaw opens normally. This is referred to as reduction since it is now in normal function.
ADDWR is not an either or situation because there can be a spectrum of severity depending on how far displaced the disc is. The more anteriorly displaced the disc is in relation to the condyle, the more severe the condition.
However, having the disc displaced anteriorly is not the only type of disc displacement. It can be malpositioned in other orientations as well.
Anterior displacement
Sideways displacement (Lateral and Medial)
Anterior rotation displacement (Anterolateral and Anteromedial)
Posterior displacement
So, why does my jaw pop?
Your jaw will pop whenever the condyle slides over the articular disc. The best analogy which we can think of, is whenever you drive over a speed bump. You feel that "bump" whenever you go over one. In your jaw's case, you feel that "pop" whenever it slides over the disc.
Here is a video which gives a very good visual description of how the jaw popping or jaw clicking occurs.
For a normal functioning healthy TMJ, the disc glides with the condyle as it moves so there is no clicking or popping sounds. However if your disc is displaced anteriorly, you will get a popping sound whenever the condyle glides over it.
Sometimes you can even get an additional jaw click when you close your jaw as the disc slides back off of the condyle once more. If you get a double jaw pop from opening and closing, it is referred to as a reciprocal click.
Reciprocal click:
The first click is when you open your jaw and the condyle slides over the disc.
The second click is when you close your jaw and the disc slides back off of the condyle.
This process happens continuously as you repeatedly open and close your mouth. Consequently it may feel like your jaw is constantly popping since the condyle keeps sliding onto and off of the articular disc.
With pain vs without pain
Depending on the severity or how displaced the disc is, the jaw popping may or may not be accompanied with pain.
No displacement:
Disc is directly on top of the condyle.
No pain since disc is avascular and has no nerve endings.
Mild displacement:
Disc is slightly in front of the condyle.
Typically no pain since part of the disc still acts as a cushion.
Severe displacement:
Disc is so far displaced that the condyle is occluding into the retrodiscal tissue.
Typically painful because the RDT is highly vascularized and innervated.
Basically if you're feeling pain from your jaw clicking it usually means that your condition is fairly severe. Your articular disc is displaced so far anteriorly that your condyle is now grinding on the retrodiscal tissue which is full of nerve endings.
Jaw popping on one side only
It is certainly possible to have jaw popping on one side only because your jaw consists of two TMJs, one on the left and one on the right. That actually makes it the most unique joint in the human body. It is the only joint with two joints!
Each joint is separate from one another so if you have clicking or popping on one side, it means that only one side is affected. However since both TMJs work together for the jaw to function, deficiency in one may soon lead to deficiency in the other.
What causes jaw popping?
There are a variety of possible causes which may displace your articular disc and result in jaw popping.
Macrotrauma - major impact to jaw (sports injuries and altercations)
Microtrauma - parafunctional habits (teeth clenching and grinding)
Systemic arthropathy - rheumatoid, SLE, psoriatic arthritis, HLA B27, infective, etc.
An alternative framework of the etiologies:
A normal joint subjected to overload (trauma or parafunction)
An abnormal joint subjected to normal load (rheumatoid, SLE or psoriatic arthritis, osteochondroma, chondromatosis)
The vast majority of patients fall under the "normal joint subjected to overload" which is mostly due to parafunctional habits. There was originally nothing wrong with their TMJ but overtime due to parafunctional habits and overuse, the disc became displaced.
Parafunctional habits that may lead to disc displacement:
Chewing gum frequently
Biting your fingernails
Grinding your teeth
Clenching your jaw
Thrusting your jaw forward
Biting your lips or cheeks
Additional risk factor
One particular study found that 88.1% of individuals who changed from skeletal class III to class II malocclusion had disc displacement on at least one side of their TMJ.
Skeletal class II = retruded lower jaw
Skeletal class III = protruded lower jaw
This is an indication that the displacement of the disc is potentially associated with sagittal and vertical skeletal deformities.
Exceptions
Interestingly, there was a study in the Journal of Oral Rehabilitation which found that bruxism may not be a risk factor for TMD. The study found that those who grind their teeth at night time had the same prevalence of TMD as those who did not grind.
Excessive teeth grinding certainly does result in overuse of the joint but this particular study found otherwise.
Prevalence
It is estimated that internal derangement of the TMJ may affect up to 28% of the population.
Jaw popping or clicking is detectable up to 31% of the population.
Crepitus is detectable in up to 40% of the population.
26% men vs 40% women
Higher prevalence in women
28% clicking for women vs 21% for men.
Mean age of TMJ disorders (TMD or TMJD) is 34 and between the ages of 15-45.
Even if you DON'T have any popping or clicking in your jaw, it does not preclude you from having a displaced disc.
Treatment
Treatment for jaw popping or more specifically, internal derangement can be separated into non-surgical and surgical treatments. However the goals or end results remain the same:
Treatment options:
Decrease joint overload
Decrease pain
Reduce inflammation
Improve TMJ range of motion
Restore all functions
Manage causative factors
Non-surgical treatment options
Patient education. Educating the patient to be conscious of avoiding daytime parafunctional habits such as clenching.
Soft diet. Eating softer foods will place a smaller load and less stress on the joint.
Occlusal splints. These are to help you reposition your jaw in a more optimal position. They are different than traditional night guards that are meant for bruxism.
Nonsteroidal anti-inflammatory medication. Take pain killers if the joint is having an acute episode.
Muscle relaxants. Tight TMJ muscles may be influencing the jaw movements.
Botulinum toxin. Freeze the overactive jaw muscles.
Physical therapy. See a PT to learn jaw strengthening exercises and stretches. Can also work out muscle knots and trigger points.
Occlusal splints
Studies have shown that an anterior repositioning splint was more effective than a flat occlusal splint in treating reciprocal jaw clicking. There was decreased joint pain at rest, chewing, and protrusion of the jaw. The jaw popping was eliminated and joint tenderness also went away.
However, once the subject stopped using the splint, all symptoms returned after 6 weeks. Therefore, the therapeutic benefits seem to be only temporary and while you're using the splint.
A different study found that a canine-protected splint was more effective than the anterior repositioning splint. The former allowed disc recapture upon closing in 40% of subjects vs the 25% for the latter.
Ultimately, a well fitting night guard can help alleviate a lot of the symptoms.
Surgical treatment options
Arthroscopy. Various procedures done through an arthroscope, a small tube with a camera.
Arthrocentesis. Flushing out the joint with needles.
Disc repositioning. Essentially the displaced disc will be manually repositioned into its proper position.
Discectomy and Arthroplasty. Discectomy is the complete removal of the articular disc.
Joint replacement (alloplastic or autogenous). The most invasive surgical option is total joint replacement. This is when the condylar head gets completedly removed and replaced by a titanium replacement.
Arthrocentesis
A minimally invasive procedure, which creates hydraulic distention by inserting two needles into the upper joint space. One needle is the inflow and the other one is the outflow. What this accomplishes is lysis and lavage of the upper joint space.
Lysis - removes adhesions, restores lubrication and synovial fluid flow, improves range of motion.
Lavage - washes away debris, inflammatory mediators, cytokines, matrix metalloproteinases, proteolytic enzymes
New studies have emerged where arthocentesis with sodium hyaluronate may be superior to the traditional lactated ringer's solution.
Arthroscopy
A minimal invasive surgery which utilizes arthroscopy. The entire procedure is done by visualizing it through a small camera.
This can be used for lysis and lavage or it can reposition the disc and fix it as well. Therefore its uses can be as simple or complex as the operator desires.
Will it go away on its own?
Surprisingly, jaw popping may not progressively get worse over time and can potentially remain the same. Sometimes they even resolved all on their own with enough time.
A 10 year longitudinal study which followed 293 subjects with jaw clicking found that it wasn't progressive in nature. At the 5 year follow up, the popping and clicking remained the same. At the 10 year follow up, only one progressed from popping to jaw locking.
A different study which followed patients over 3 years found:
71% of the clicking remained unchanged.
29% of the popping spontaneously disappeared.
Last but not least, probably the best news that you can hope for... A study in the Int Journal of Oral Maxillofacial Surgery found that 68% patients with jaw popping and jaw clicking had resolution of all symptoms after 18 months without any treatment.
Therefore it is possible for it to go away on its own or it may not get worse. However that is not to say that it can't get worse because it certainly can if you happen to be one of the unlucky ones.
Potential progressions of internal derangement
According to the Journal of Canadian Dental Association, internal derangement can be classified into 4 clinical stages.
Stages of internal derange of TMJ:
Stage 1 - Reciprocal jaw clicking as a result of anterior disc displacement with reduction.
Stage 2 - Encompasses stage 1 but with occasional episodes of jaw locking.
Stage 3 - Closed lock or disc displacement without reduction. Typically the patient will have trouble opening or not being able to open at all. There is no clicking since the jaw can't even open.
Stage 4 - Retrodiscal tissue may be stretched thin or perforated. Crepitus sounds may be present.
Summary
Jaw popping is a result of internal derangement of the TMJ, where the articular disc is displaced anteriorly but can be reduced. The popping sound occurs when the jaw opens and the condyle slides over the disc.
Sometimes the disc can slide back off of the condyle upon jaw closing, resulting in an additional second click.
Fortunately there are many treatment options available but the best news is that it can potentially go away on its own. There are even cases where it never gets worse either.
