What is a ‘jaw lock’?

If one’s lower jaw (known as the ‘mandible’) is stuck in either a closed or open position, it is commonly called a ‘jaw lock’ which is a joint disorder. If the jaw closes OK, to get the teeth together, but cannot open the mouth very far, it may be a ‘closed lock’. Normal opening should allow about 2 inches (50 mm) between front teeth. Limited opening of about 1 inch (less than 30 mm) may indicate a closed lock. Open locks typically occur at over 2 inches between front teeth; but it can happen at much less in some instances. If your opening your mouth, but are unable to get the teeth back together, because your jaw gets stuck try to relax and message your jaw.

A locked jaw may occur suddenly with no prior history, after an injury to jaw or following a history of ‘catching’ or ‘intermittent clicking locking jaw’. This is a condition where the jaw gets stuck momentarily either in a closed or wide open position but then gets unstuck immediately. Most times people ignore this ‘catching’ since they are able to function once the jaw gets unstuck readily and because this is usually a pain-less condition at that point.

Are all ‘limited opening’ due to “closed locks”?

There are many causes of limited mouth opening including pericoronitis (infection around a partially erupted molar tooth such as a wisdom tooth), myositis (inflammation of a jaw muscle – for example, that was injured from repeated dental anesthetic injections), jaw muscle spasms (like a Charlie horse), Disc Displacement without Reduction (“Closed Lock”) and others. This can cause pain, prevent normal chewing or speaking and adequate oral hygiene. When the mandible is unable to have normal range of motion it can lead to headaches, neck pain etc.

What causes “jaw popping” and “closed locks”?

Inside the joint located in front of the ear hole, there is a cartilage –known as the ‘articular disc’, between the ‘socket’ which is part of the temporal bone of the skull and the ‘ball’ called condylar head that is part of the mandible. Normally tough collagen fibers -collateral ligaments, tie down the discs on top of the condylar head. It is like a cap on a person’s head if it were tied down to both ears allowing it to slide on top of the head within limits. The disc is also tied down in the back of the socket like a tether and in the front to a small muscle that moves the disc as the jaw opens.

The disc can only slip out when some of the fibers of this collateral ligament are torn. If it slips in front or medial side of the condylar head when teeth are together but yanked back into place, on top of the ‘ball’ by the ‘tether’ in the back of the socket, with a popping sound as the mouth is opened slightly, then it is called ‘Disc Displacement with Reduction”. This is the common jaw popping that many people casually report since there is no pain. Many dentists that are uninformed of the process of tearing of the ligament and damage to the joint over time, also dismiss this as “normal” since it does not hurt and relatively common in our modern population.

Heart disease is painless in the early stages and fairly common among western populations as well. But no one will consider that as “normal”. If an articular disc slips in front or medial side of the condylar head when teeth are together, bunches up to prevent opening of the mouth, then it is called a Disc Displacement without Reduction (“Closed Lock”).

Why does the “jaw popping” go away by itself for some people?

When a discal ligament has so many torn fibers that it has become very loose –known as a “lax ligament”, and the disc is no longer yanked back into place when the mouth opens, the “click” disappears. Often, patients are happy to report that they no longer click as they used to. Little do they realize that even though there is no pain at this time, the ball and socket of the joint now function without the benefit of the disc to cushion the movement.

Over time this bone to bone contact leads to deterioration. Just as any joint in this situation, it may lead to Osteoarthritis due to wear and tear. It is hard to function with such a condition. Unlike a knee, for example, that you can rest by not walking much, the jaw needs to move when speaking, swallowing hundreds of times a day and even for eating soft foods. Actual patients have said that they can’t even eat a banana without excruciating pain when their joints have reached this stage.

What are the options to fix “closed locks”?

Patients often hear that the only way to fix it is through surgery. But we have successfully treated joint locks without surgery for several years. All joint surgical procedures have associated risks including infection and anesthesia risks. Long term success rate is mixed since the surgical procedures do not usually address the underlying cause that led to the Disc Displacement without Reduction. One may “unlock” through an arthrocentesis procedure where an anesthetic solution is injected through a needle into the joint space which lubricates, fills and numbs the joint allowing the disc to be unlocked. Surgeons usually caution the patients that it is only a temporary relief since the underlying poor jaw alignment that caused the lock is not addressed through this procedure. Another option is an open joint procedure called “disc plication”. Under general anesthesia, an incision is made in front of the ear to open the TM joint, locate the disc and suture it into place. This is a more invasive procedure with increased risks. Success rate for such procedures have been quoted as “80% chance of improving as much as 50%”. So 20% may have worse symptoms and the maximum improvement one can hope for is 50%. Due to this and other reasons, most Oral Maxillofacial surgeons do not do this surgery any more.

Non surgical options include Neuromuscular dental protocol of precisely diagnosing the optimal alignment of the mandible to the head and temporarily correcting the jaw alignment with a NM orthotic to get the disc in place. Only when there is substantial improvement of the symptoms, we would consider long term stabilization options such as NM Functional orthodontics (see Colleen’s case history) to move the teeth into the improved positions to hold the jaw in the new position, NM Full mouth reconstruction (see Paula’s case history) or a combination of procedures (see Debbie’s case history).

Stop living with clicking, locking, and popping Jaw.

Move your jaw joint open or closed without pain and inflammation. For medical advice or diagnosis on how to unlock your jaw schedule an appointment and find out how treatment from a TMJ specialist doesn’t just mask the symptoms, it can fix TMJ disorder for good.