TMJ 
The Temporomandibular Joint
An Overview

What is the TMJ? 

The TMJ is a sliding "ball and socket" joint; there are two connected to the lower jaw. The TMJ is considered to the the most complex joint in the human body. The TMJ is a complex joint and its actions are influenced by: 

  • Teeth-bite (occlusion)  
  • muscles 
  • jaw bones 
Each member of this "trio" has a part to play in the harmony of your TMJ. Muscles should be relaxed, flexible, and work symmetrically. Teeth are well aligned in a balanced, stable bite allowing simultaneous contact of all teeth when biting or chewing. Both jaw joints should open and close comfortably and be free from damage due to injury or trauma. 
 
TMJ anatomy
TMJ anatomy is compromised of: 
 
  • Condyle: The round end "ball" of the posterior portion of the lower jaw, or the mandible.
  • Muscles: Group of muscles that contract and relax so you can open and close your mouth, talk, and chew.
  • Disc: Is a "shock absorber" that provides gliding action between the upper and the lower jaw.
  • Ligaments: They hold the disc to the condyle.
  • Connective tissue: Attaches the disc to the back of the joint while allowing blood and nerve enervation.
TMJ DISORDERS  
 
Because the muscle, joint and bite trio perform together, a problem arising from any one of these can lead to a TMJ disharmony. Muscular problems such as clenching or grinding "Bruxism" or poor posture can result in tightening and tension in the muscles, with consequences such as headaches, joint stiffness, pain around the TMJ. Malocclusion (bad bite) disrupts TMJ posture, introducing stress points for example an anterior open bite allows the posterior teeth to only come together. This can displace the condyle and possibly move the disc out of position possibly causing clicking sounds or "Lockjaw". Jaw bones may have an adverse effect on the joints in cases of trauma. A sudden impact may over-stretch the ligaments allowing the disc to slip out of position and even lead to arthritic degeneration.   
TMJ DIAGNOSIS 
 
In order to evaluate a TMJ disorder a dental/medical examination is necessary. This will include a medical history review, physical exam, dental study casts to determine if the teeth have the correct and balanced occlusion (contact), and some diagnostic tests such as:  
  
  • Tomographic or Transcranial x-ray: Head x-rays that reveal images of bone structure, joint damage, fracture or tumors.  
  • MRI (magnetic resonance imaging): Produces detailed images of the soft tissue, revealing damage in the disc or the ligaments.  
  • EMG (electromyogram): Measures muscle tension and consequently tightness. 
TMJ TREATMENT OPTIONS
 
There are many different approaches to relieving the discomfort associated with TMJ ranging from simple self-care programs to surgical intervention. It is strongly suggested that you do not use this information to self-diagnose and seek professional advice as this information is only intended to enhance your communication with your dentist.   

I. Self-care  
Sometimes your dentist may suggest simple methods to alleviate discomfort. These can include:    
Resting your jaw, muscles relax and take the pressure of the joint.   
Ice and heat application, ice helps reduce swelling. Both ice and moist heat help relax muscles and reduce pain.   
Exercising the jaw, gently open and close in a straight path a few times and repeat this motion 3-4 times daily. Exercise can restore the normal range of motion.   
Medications, while Aspirin may be a sufficient pain killer there are other analgesics you can use subject to your dentist's discretion. Your doctor may further prescribe a muscle relaxant or anti-inflammatory to combat swelling.  

II. Stress management  

Daily stress management is one of the best methods of restoring harmony between your muscles and the TMJ. Often times obtaining support helps you cope with stress and pain accompanying a TMJ disorder. Your dentist will be able to evaluate the possible suggestions for your TMJ disorder.    

  • Biofeedback: Electrodes are placed on your jaw muscles. They will in turn measure your muscle tone and produce respective signals. This technique helps you see what is going on inside the muscle and the forces placed on it so you can consciously control your body's stress responses.  
  • Relaxation Techniques: Some individual techniques include, deep breathing, self-hypnosis and yoga.  
  • Support Groups: Your dentist may be aware of support groups that can help you with stress management, ease of isolation caused by the chronic pain, or contact other TMJ patients. 
III. Physical Therapy  

Physical therapy is often used after surgery or in cases of disc, ligament or other joint tissue injury. Some of its applications in treatment of a TMJ disorder may include:    

  • Jaw Exercises: Improving strength, range of motion and posture of the muscles around the joint.  
  • Postural Training: Your head and neck posture may affect your TMJ problem. Holding your head erect helps improve the posture of your jaw.  
  • Electrical Stimulation: An electrical stimulus sent through your skin causes muscles to gently contract This both exercises and relaxes muscles, aids circulation, and often relieves pain.  
  • Mobilization: Releasing restrictions around the joints and the muscles improves range of jaw motion, reduces stiffness and pain.  
  • Ultrasound: Sound waves can improve circulation, reduce pain, decrease swelling and improve range of motion.  
IV. Occlusal Splint 
  
A splint is a clear appliance that fits over your upper or lower teeth. It aims to establish harmony between the muscles, bite and joint. Splints may reduce Bruxism (grinding) by introducing a space between your teeth. 

There are three main types of splints:  

  • A night guard (bruxism splint)
  • Repositioning appliance
  • Orthopedic stabilization appliance
It is estimated that over 80% of TMJ disorders can be treated with this mode of therapy. 

V. Occlusal Adjustment (Equilibration)   

Each time you bite or swallow your teeth will interdigitate just like the grinding gears of a car. The cusps will slide into the grooves of the opposing teeth. If this mechanism is disturbed, the uneven forces applied during chewing will be transferred to the TMJ causing pain and malfunctioning of the joint.  
This may be remedied by:    

  • Selective Grinding: The cusps and the grooves are slightly reshaped to allow a uniform and balanced bite.  
  • Restorative Dentistry: Old restorations interfering with your bite are replaced. Some teeth may require a crown and missing teeth areas are filled using partial dentures, bridges or implants.  
  • Orthodontics: In specific cases the ideal position of the teeth may be reached by merely moving them, with the help of braces.  
  • Surgery: In rare occasions a patient may require a procedure that realigns the jaws called Orthognathic surgery along with orthodontic work. 
VI. Surgery 
  
With all the alternative modes of therapy, surgery is rarely needed, especially if the problem is diagnosed and treated early. However a severely damaged joint (ie, jaw will not unlock) needs corrective surgery. Different modalities in surgical intervention may include Arthroscopy, Soft tissue repair and Joint reconstruction. After the surgery you may need other supportive treatments, like self care, physical therapy, or a splint as to enhance the final results and prevent future TMJ problems.  
Menu