Locking Jaw – Limited Mouth Opening

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by Clayton A. Chan, DDS
Limited mouth opening or what is commonly known as “Locking Jaw” or limited mouth opening is a condition that few dentist in the dental profession really understand or know how to treat without thinking they have to refer to an oral surgeon to either  ”scope the joints”, lavage the joints with a solution and/or mechanically unlock the jaw using some form of manual manipulative techniques to open the jaw under sedation.  To most dentist this problem is often a bewildering problem which many believe is outside their scope of care, thus muscle relaxants are prescribed as a means to hopefully relax the muscles to unlock the jaw, but this often does not work.

A limited mouth opening or a restricted jaw opening is when the condyles are not able to move downward and forward the height of the articular eminence of the jaw joints.  This can be observed on a jaw joint radiograph film using tomograms, cone beam, MRI imaging technology.  The patient is asked to open their mouth as wide as possible and the film can be taken at that position to identify whether the jaw joints show restriction on wide opening.

Note: Picture to the left shows a a patient with a very restricted opening of one finger wide open with pain for the past 10 years.  Center picture shows restricted TM Joints – left and right condyles are not able to move down to the articular eminence.  Right picture shows patient now able to open wide with no TM joint restriction with three fingers between teeth.

If the condyles are able to move down and forward to the articular eminence (seen on radiographic imaging) this is not a restricted or limited mouth opening.

Patients become further frustrated and become fearful furthering  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, presenting as a form of  TMJ.

Because of the pain from the limited jaw opening, some health care providers try to do the following:

  • Botox injections to rid the pain with no long term resolution.
  • Prescribe anti-depressants and pain medications.
  • Oral surgeon attempt to clean the joints (joint scopings) or do a lavage or wash the joints with saline/cortisone, with limited help.
  • Acupuncture
  • Physio therapy
  • High frequency TENS
  • Medications
  • Splint therapy – anterior repositioners, thick splints, deprograms, thin splints, NTI
  • Message therarpy
  • Osteopathy
  • Cranio sacral

Why is this happening?  Most dentist and health care professionals are not getting to the source of the problem!  Many of them are trying to treat the problem with out addressing the cause.  But as the public is finding out the dental professionals don’t always understand the cause, so how can they be relied upon to remedy the problem?

When a jaw is able to open and close from a biting position to at least one to one half fingers wide,  there is hope.  This is not a “true closed lock” problem (structural restriction vs. a muscular  restriction as in most  limited mouth opening cases).  Most dentist do not understand how the jaw joints work since most are concerned about the teeth and gum tissues.  Few dentist are trained in understanding how the jaw joints work and function.  Even fewer understand and know how to effectively and non invasively treat the limited mouth opening or “locking jaw”.

Limited mouth opening or locking jaw can be due to the following:

  1. When there is an over closed bite and jaw joints (condyles) are in an up and back position within the glenoid fossa causing the articular disc to be displaced forward.  This is abnormal causing the jaw to be restricted in mouth opening.  Facial pain, pain behind the eyes are also a part of this problem.
  2. Braces (retractive orthodontics – headgear, bicuspids and or molars extracted  due to seemingly limited space) which were designed to straighten teeth and close spaces, but  in the end caused the lower jaw to be entrapped (restricted)  behind the upper jaw forcing the jaw to go back when the teeth come together.  During normal speaking, the  jaw commonly functions in an unrestricted opening and closing path, but when the patient voluntarily tries to bring their teeth together they are forced to move the lower jaw back to close their teeth (bite) together.  This causes the both condyles (jaw joints) to distalize or go backward within the glenoid fossa and the articular disc can be displaced forward (abnormal) when the back teeth do not have adequate vertical height to prevent the joints (condyles) from intruding in an upward and backward direction causing accompanied muscle tension and ear congestion feelings.
  3. Bite adjustments – teeth are equilibrated or posterior teeth are ground down.
  4. Removing fillings and or restorative dentistry and root canals – vertical dimension of the bite is lost or diminished during treatment

Key to Effectively Unlocking the Jaw without Invasive Forceful  Treatment

Individuals should be able to normally open with 3 fingers together between their front teeth without pain.  Anything less than three fingers wide and with pain should be evaluated by your dentist.

  • Relaxing the muscles is the objective, but relaxed muscles will not occur until proprioceptive feedback mechanism from the clenching bite is over come.
  • The jaw joints (condyles) must be decompressed within the jaw joint (glenoid fossa) to allow adequate space for the articular disc to reposition back to a normalized and function state (reduce).
  • For disc to reduce and condyles to be decompressed downward the bite must be relaxed with either cottonrolls or some form of tongue blades or a combination to further a mechanical opening of the back  teeth to help improve the TMJ positioning.
  • Low Frequency TENS can be also added to this process to help relax the spastic muscles.
  • Using K7 Jaw Tracking technology combined with the Optimized Bite capturing protocols with low frequency TENS to measure and objectively to determine an optimal jaw position.

Most jaw joint experts in the TMJ field can be effective in resolving locking jaw (limited mouth opening problems) without surgery and or invasive procedures within the dental profession as long as they have a thorough understanding of how the muscles, jaw joints and occlusion (teeth) operate and function.  Unlocking the jaw is possible without invasive surgical procedures and without prescription medications!

Clinicians knowledge, understanding, skill and expertise is required.

For more information contact: Dr. Clayton A. Chan at jane@drclaytonchan.com or (702) 271-2950.  Las Vegas, NV .

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The Originator of the Chan Optimized Bite™. He is considered by many to be the authority on Neuromuscular Occlusion and its application to Clinical Dentistry. Dr. Chan is a general dentist, clinician, teacher, educator and leader .

Director, Occlusion Connections™ Center for Gneuromuscular Dentistry & Orthopedic Occlusal Advancement
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3 Responses to “Locking Jaw – Limited Mouth Opening”

  1. i am 35 years old. my jaws started closing when i was ten years old. the process of jaws closing was very slow. i did not care for that. now the condition is that my mouth opens less than inch. i am unable even to eat meal. kindly tell me the treatment or physiotherapy available in Pakistan.

  2. My lower jaw will not open wide enough since a couple of days after a lower filling on right side.very painful
    Can you helpp please
    David Manharan
    Kisimmee Fl.

  3. i am mouth cancer patient and i have also opreting the cancer and my mouth are not open properly pls suggest what can i do?

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