TMJ Dysfunction is a popular term to describe a disorder of the jaw
joint or the muscles that control the joints. Dentists use various
terms to describe this same disorder. In this pamphlet, we will
use the dental term 'Craniomandibular Dysfunction'. Symptoms masquerade
as a multitude of other problems, such a sinus headaches, migraines,
neck and shoulder stiffness, and earaches. This pamphlet explains
how such symptoms may relate to your bite and how they can successfully
be treated by your dentist.
Craniomandibular Dysfunction is a dental term which
describes a collection of symptoms which result when the chewing
muscle and jaw joints do not work together correctly.
'TMJ' is a popular term commonly used to describe the same group
of symptoms. The TMJ stands for Temporomandibular Joints. These
are the two joints that connect your jaw to your skull. When these
joints are out of place they can cause many problems, such as:
- clicking or popping of the jaw joints
- pain in and around the jaw joints
- locking or limited opening of your mouth.
Muscle spasm goes hand-in-hand with displaced jaw joints. Because
the nerves and muscles are so complex in this area, when these muscles
are in spasm the problems can be far-reaching. People suffer from
symptoms they would never think to associate with their bite, such
- pain behind the eyes
- earaches and ringing of the ears
- clenching or grinding of the teeth
- neck, shoulder or back pain
- numbness, or tingling of the fingers
The primary problem can be in the joints themselves, the muscles
of the face and jaw, or a combination of these. The term Craniomandibular
Dysfunction (cranial = head; mandibular = jaw) is a more descriptive
term because it refers to problems involving both the face and head.
Because the symptoms masquerade as so many other conditions, many
people travel from doctor to doctor in search of a cure. It is estimated
that as many as one in six people suffer from one or more of these
symptoms. Many never think to seek a dentist for help.
What Causes Craniomandibular Dysfunction?
The structures that make it possible to open and close your mouth
include the bones, joints, and muscles. These are very specialised
and must work in harmony whenever you chew, speak or swallow.
Your teeth are inserted into jaw bone. At the other end of your jaw bone
are the temporomandibular joints. These joints attach your jaw to
your skull. Muscles attach both the bones and joints and make the
move. Any problem which prevents the complex system of muscles,
bones, and joints from working together in harmony may result in
A 'Bad Bite'
There are various ways this system can be disrupted, such as accidents
involving a blow to the face or whiplash. Yet the most common cause
of craniomandibular dysfunction relates to your teeth and your bite.
If your bite is not right, it can affect both the muscles and the
joints. What do we mean by a 'bad bite'? We mean that your upper
and lower teeth do not come together in a way that provides the
proper bracing support for your jaw against your skull. This might
result from a missing tooth, misaligned teeth, or back teeth which
are too 'short'.
Your upper and lower teeth must come together firmly
each time you swallow. This happens over 2000 times each day and night!
When your bite is unstable your muscles must work extra hard. This
extra work makes them shortened and stiff. Eventually this strain
makes them feel painful. A vicious cycle begins of increased tissue
damage, muscle tenderness, and pain. The pain makes you feel tense.
This worsens the muscle spasm, which in turn increases the pain.
Jaw Joint Displacement
The position of your teeth can also affect the position of your
jaw joints. Each jaw joint is a complex sliding joint. When functioning
properly the ball and socket do not actually touch because a thin
layer of cartilage sits between them. The disc acts as a cushion
and allows the joint to move smoothly. Each disc is held in place
and guided by muscle. If your bite is not right, the joint is pulled
out of alignment. Typically the disc is pulled forward. Since it
no longer serves as a cushion, the ball itself now rubs against
the bony socket and presses on pain fibres. Mild displacements cause
a clicking or popping sound in the jaw joint; more severe displacement
can be very painful eventually can cause permanent damage to the
An unstable bite can cause both jaw joint displacement
and muscle strain and pain. Many seemingly unrelated symptoms result
which are collectively known as Craniomandibular Dysfunction. When
this condition is prolonged, the body begins to compensate and adapt
by involving muscle in the neck, back, and even sometimes those
of the arms, fingers, pelvis, legs and feet. Since the teeth, jaw
joints, and muscles can all be involved, treatment for this condition
varies. Typically, treatment will involve several phases. The first
goal is to relieve the muscle spasm and pain. Then your dentist
must correct the way the teeth fit together. Often a temporary devise
(known as an orthotic, or 'splint') is worn over the teeth until
the bite is stabilised. Permanent correction may involve selective
re-shaping of the teeth, building crowns on the teeth, orthodontics,
or a permanent appliance to lay over the teeth. If the jaw joint
itself is damaged, it must be specifically treated, though infrequent,
surgery is something required to correct a damaged joint. Ultimately,
your dentist will stabilize your bite so that the teeth, muscles,
and joints all work together without strain.
The important aim of correcting your bite is to
ensure optimal long-term health. If you have any of the signs or
symptoms mentioned, discuss them with your dentist.