What is LockJaw?
Trismus (or lock jaw) is a condition in which someone has severely restricted mouth opening. It is a problem commonly encountered by dental practitioners, and responds well in the hands of a trained physical therapist. Trismus has a number of potential causes which range from simple and non-progressive to those that can be potentially life threatening. Knowledge of the normal range of mouth opening is essential in the diagnosis and treatment of trismus. It varies from patient to patient within a range of 40-60mm. 2 finger (~40mm) to 3 finger breadth (~54-57mm) is the usual width of opening.
Trismus is often defined as a mouth opening of less than 20mm. Other classifications include:
Mouth opening of > 30mm but < 40 mm indicated light trismus
Mouth opening of 15-30mm indicated moderate trismus
Mouth opening of < 15 mm indicated severe trismus (less than 1 finger breadth)
Limited mouth opening often poses challenges in the following areas:
- Dental examination and treatment
- Oral care including cleaning your mouth and teeth. This may lead to bad breath, cavities, and infections
- Eating, drinking, chewing and swallowing
- Talking
- Kissing
- Medical care if a breathing tube is necessary (emergency or surgery)
Lockjaw Causes
- Infection
- Odontogenic (tooth related)
- Pulpal
- Periodontal
- Non odonogenic
- Tonsillitis
- Tetanus
- Meningitis
- Parotid gland abscess
- Brain abscess
- Odontogenic (tooth related)
- Trauma:
- Surgical extraction of the mandibular molars
- Post anesthetic injections; inferior alveolar nerve block, posterior superior alveolar nerve blocks (this is the more common reason we see clients with trismus due to trauma to the Medial Pterygoid muscle)
- Direct trauma involving facial and mandibular fractures
- Dental treatment
- Temporomandibular Joint (TMJ) disorders
- Tumors including benign and malignant lesions involving oral cavity and submucosal areas
- Drug induced: Some drugs are capable of causing trismus as a secondary effect, phenothiazine, succinyl choline and tricyclic antidepressants being more among the most common. Trismus can be seen as extra pyramidal side effects of metaclopromide, Phenothiazine and other medications.
- Radiotherapy and chemotherapy: Fibrosis (scarring) may build up years after therapy
- Congenital disorders
- Miscellaneous disorders include Hysteria and Lupus erythematosus
- Fibrosis as a result of local surgery
How to Diagnose lock jaw / Trismus
The spatula test is a simple way to diagnose trismus. The posterior pharyngeal wall is touched with spatula and a reflexive spasm of the masseter occurs (positive) instead of the normal gag reflex (negative).
Once trismus develops, it is very hard to treat. That is why prevention and early recognition are essential to patient outcomes. It is important to see a physical therapist specializing in Temporomandibular Dysfunction (TMD) as soon as possible. They will provide manual treatment to the muscles restricting jaw motion and home exercises to restore opening. It is also very important to see a physical therapist with skill and specialized training in the area of TMD to prevent the possibility of developing a TMJ disc disorder.
Lockjaw Treatment – Physical Therapy Examples
- Sustained stretching with tongue depressors, with or without heat related modalities
- Manual soft tissue mobilization to the involved muscles, as well as teaching the patient self-massage, particularly to the medial pterygoid
- Teaching the Finger Spread technique for home stretching.
- If capsular tightness develops, graded and gentle joint mobilizations
Physical therapy treatment objectives include removing edema, softening and stretching fibrous tissue, restoring circulatory efficiency, increasing muscular length and strength, and ultimately recovering full functional range of motion. The earlier patients with trismus receive physical therapy, the faster they will recover normal opening. Some more challenging patients, post radiation cases and others who are undiagnosed for months may take several months to recover.
Do you have lock jaw? Do you have more questions on lockjaw symptoms, causes and treatment? Comment below and let me know.
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My husband was treated for throat cancer and a result of the surgery, radiation and chemo he has trial is. We found 3 physical therapists in Bend Oregon who he had some good results from their specialized training. We have moved to Southern .ca now to be near family and his doctors but we can’t find a PT who can treat trial is. He has had some good luck with botox shots in his jaw muscle. Do you have a referral anywhere in So Ca for a qualified PT? HELP!
I have a lock jaw admitting one finger not two. Its very painful. Its beeb three days now. I am taking anti-inflammatory drugs and I have lupus. I am afraid to go to a doctor due to covid-19 scare.
Hello,
If you are interested in a phone/video consultation, you can fill out a form here https://www.treatingtmj.com/tmj-consultation/ and our office will contact you to set up an appointment. Let us know if you have any other questions!
I’ve had lockjaw for 35 years, is there any hope for me?
SIR MY WIFE HAS GOT LOCKJAW AFTER CLEANING OF TEETH BY DENTIST ,BEFORE THAT SHE HAS PAIN IN WISDOM TOOTH ALSO, WHICH HAS TO BE PULLED OUT BUT FIRST DOCTOR DONE CLEANING.WHY JAW LOCK
My jaw won’t open more than 20mm. I was given 3 different medications. Apparently it’s inflamed. It’s been 8 days and hasn’t improved 😩 I’m scared
I had a dentist visit to get a molar pulled on the right lower side and 2 fillings,1 on each side of upper jaw.the woman givi ng me numbing shits siad she accidentally hit a blood vessel on the left side of my mouth and now i can barely open my mouth to eat.i can hardly get 2 fingers in my mouth.all they did was give me a mold for a night gaurd. Is there anything else i can do..any advice
Hello, I am very sorry to hear this, it does appear you might have trismus. First important to make sure you do not have any low grade infection from the procedure, in which case if you do and you are not allergic and able to tolerate an antibiotic medication, that can help eliminate the infection and usually jaw opening will resume in 7 to 10 days. If what your dentist is indicating is accurate and from the injection you possibly suffered a hematoma of your medial Pterygoid muscle than in my opinion, you really need to find a very good TMJ PT near you and immediately start receiving physical therapy to get intra oral soft tissue work done to your medial pterygoids, gentle mobilizations and gentle low grade, prolonged stretching to resume your normal opening. I cannot stress enough the sooner the better, the longer you wait and do not open, the more contracted and fibrotic your tissues will get and the longer, it will take to get things back to normal. Keep us posted. Thanks, Mike
I need some help I do have lock gar
I had root canals on two teeth. Half completed. Two weeks later saw jaw would not open more than 11 mm
I now have severe lockjaw and pain is beginning to ensue from incomplete root canal. I cannot hardly eat. It’s been 30 days I am very fearful
Hello Molly, i appreciate you reaching out and I am very sorry to hear this. So 2 initial thoughts come to mind after a procedure like you had done, 1. you could have a low grade infection causing the trismus, so have they tried putting you on and antibiotic?? 2. Next, a probable hematoma in the medial pterygoid from the anesthetic block in which case since it has been 30 days your really, really need to find a PT trained in treating TMJ in your area now to be shown the tools to start stretching and getting you open. Once they get you more open to say 30mm or so then we can also determine if you might have an underlying disc related issue as well. But it really is imperative you seek help asap to stop your tissues from getting more fibrotic and then it will take it even longer to get your opening back to normal. I have seen patients 5 months plus out with trismus and we are still able to get them back open, but you might only gain 1mm a week or 4mm in a month so it is a very slow and long process. And you Must, Must follow your home program each day, etc Keep us posted!! All the best, Mike
Back Dec. 17 0f 2023 I woke with abscess tooth under a cap tooth. Terrible pain . I ended up going to an emergency dental clinic got it pulled. I couldn’t open my mouth , I found I had trimus which is lockjaw. I’m 66 years old so that was scary as it happened all without warning. My jaw still pops when I eat. Weird.