Locking Jaw – Limited Mouth Opening


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.”

CLOSED LOCK: Is when the jaw is closed in a biting position and the patient is unable to open the mouth very far. A normal opening should allow about 3 fingers between front teeth. Limited opening of less then 2 to 1 finger may indicate a closed lock.

OPEN LOCK: Open locks typically occur at over 2 to 3 fingers between front teeth; but it can happen at much less in some instances. If your patients mouth is open, and you are unable to get the teeth back together, then it is called an “open lock.”

A jaw lock may occur suddenly with no prior history, after an injury to jaw or following a history of ‘catching’ or ‘intermittent jaw locking’. 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.


1. RELAX: Let your jaw just drop. Get it relaxed. You should be able to wiggle it freely side to side (with your hands) without your jaw muscles resisting.
Patients become further frustrated and become fearful perpetuating the pain cycle with tightness of the masticatory muscles, by further clenching and tightening of the jaw muscles. Facial pain, neck pain, pain at the top of the head, and behind the head and neck, with pain behind the eyes and/or pain around the eyes and tenderness as the lower border of the corner of the lower jaw are just some of the problems patients can experience.

2. MOIST HEAT APPLIED TO BOTH SIDES OF THE JAW FOR 45 MINUTES TO HELP RELAX THE JAW MUSCLES: Washcloths will not work because they cannot hold heat long enough to be of therapeutic value. Maybe a heating pad.

3. WIGGLE, WIGGLE, WIGGLE! Sometimes a jaw can be unlocked by just moving the mandible around in weird ways until the disk pops back into place on its own. This is a hit and miss thing at best but sometimes works.

4. REDUCE THE JAW: Put your palms against the side of your patients jaw (around the side burns) and your thumbs on the ridge behind the last tooth and wiggle the jaw side to side, opposite vertical motions, forward and backwards (like overbite, underbite) pushing. It helps if your jaw is dropped and completely relaxed when you do this.

If you are not able to “reduce” the locked jaw, call Dr. Ansari at Lowes Island Dentistry.


Inside the jaw 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.

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”).


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.


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.

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 to move the teeth into the improved positions to hold the jaw in the new position, NM Full mouth or a combination of procedures.

Please contact us at Lowes Island Dentistry as Dr Ansari is able to fabricate the NM functional Bite splint.

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