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The trials and tribulations of TMD patients
Murphy's law of dentistry states quite simply;
"If any complication can arise from any dental procedure, patients who exhibit
the symptoms of TMD will probably have that complication!"
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Headaches, earaches
and neck aches: Constant bruxing
overworks the chewing muscles and causes them to get "cramps". Because
of the way these muscles are leveraged, these cramps manifest as
headaches and neck aches, and sometimes
earaches. These symptoms occur at the times these
habits are most active. Hence, if your symptoms happen in the morning
on waking up, you are probably bruxing in your sleep. If they happen
while working on a computer, then the headaches are caused by bruxing
(grinding) or clenching while
concentrating, and not by rays emitted by the CRT. These habits are
especially active when you have been under stress, such as when you are angry at your spouse or children, or during times of
personal or family crisis.
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Neck aches
(and headaches) are due to hyperactivity in the sternocleido-mastoid
muscles (SCM) and the trapezius muscles.
The SCM's are
straplike muscles that originate from the sternum (breastbone) and the
clavicle, and insert into the mastoid processes just behind each ear. This muscle
becomes active during clenching, although the reason for this is not
especially clear. This muscular hyperactivity appears to be a
reflex due to the strong, isometric contractions of the masseter and
temporalis muscles when the patient clenches.
Click here for an academic reference. The
sternocleidomastoid is the major muscle responsible for tilting and turning
the head to either side, and also for nodding the head forward.
Another pair of muscles that operate in opposition to the SCM's are the trapezius muscles
which originate along the shoulder blades and insert into the base of the
skull. The trapezius is responsible for pulling the head backwards and
may also be involved in both neck aches and headaches.
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 Earaches due to bruxing are
due to muscle cramping
from overuse of the
lateral pterygoid muscles, which are responsible for drawing the lower jaw forward. These little muscles
are located directly in front of the ear, and pain associated with them
refers
to the ear itself. When they work independently, the lateral
pterygoids are responsible for lateral (side to side) movements of the lower
jaw and hence are heavily active when bruxing (grinding) the teeth. Spastic activity in
one or both lateral pterygoid muscles is responsible for the clicking and
popping patients experience when the internal anatomy of the joint itself
has been damaged. (See my page on
occlusion.)
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Sore jaws and teeth upon waking
in the morning: Nighttime bruxing commonly leads to sore jaw muscles
when getting out of bed in the morning. Persons experiencing this
particular symptom should be especially aware that severe nighttime bruxing
is part of a larger sleep disorder, and frequently is a sign that the
patient may be experiencing obstructive sleep apnea. Sleep apnea
is a syndrome in which the patient's throat becomes so relaxed that the
airway becomes blocked, and he or she stops breathing for short intervals.
Eventually, the body becomes so starved for oxygen, that the patient either
wakes up (usually with a gasp) or arouses to a level of sleep in which he
regains muscular control of the throat muscles and begins breathing.
Warning: If you experience these symptoms, please read my page on
snore guards and sleep
apnea. Sleep apnea is a very dangerous syndrome, and
may lead to numerous other problems, including early death. Read about
the other symptoms to see if you should see a physician to schedule a sleep
study!
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 Clicking and popping TMJ's: Constant
bruxing places tremendous pressure on the temperomandibular joint as well as
the teeth.
The joint contains a cartilage meniscus
(called the articular disk) that lives between the ball and socket. Constant pressure on
the joint due to bruxing may cause the meniscus to tear. When this
happens, the ball and socket may "snap" together suddenly when the patient
opens the jaws wide due to interference from the torn meniscus. This
symptom is not generally associated with pain. (Click on the image to
see it full size)
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Difficulty opening the mouth, or remaining open at the dentist's: People who
are chronic bruxers have a very difficult time keeping their mouths open
at the dentist's office. The reason for this is that the muscles
that close the jaws are paired with others that open them. When the
muscles that open the jaws are active, the muscles that close the jaws are
supposed to reflexively relax. Unfortunately, these muscles are so
used to being in a contracted state due to constant bruxing that when they
are forced to relax, they cramp, or go into spasm. This is why so many people have
such an awful time in the dental chair. People with this problem may
open wide at first, but slowly close down over a few minutes limiting the
dentist's ability to work in the mouth. (Note: If you have this problem in
the dentist's chair, simply ask for a "mouth prop". This is a
rubber block that is placed between the upper and lower back teeth on the
opposite side of the mouth from where the dentist is working. As the
name implies, it props the mouth open taking the stress off the muscles that
make it so painful to stay open. As a matter of fact, if you actually
put extra pressure on the prop, biting down with some force, it can relieve
muscle spasm and the attendant pain of staying open for long periods.)
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Trismus: A more severe limitation in
opening the mouth is called trismus.
It may be so severe that it may be impossible to open the teeth
more than a few millimeters. This condition is most often caused by
spasm of the muscles which close the lower jaw. Whenever the patient
tries to open wider than this amount, the muscles reach a "trigger point" at
which they go into spasm and refuse to relax. A less frequent cause of
trismus is locking at the joint itself due to advanced internal
derangements.
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Frequent jaw
dislocation: Bruxing puts
constant pressure on the joint, and can stretch the
ligaments
that hold the joint together. These ligaments are supposed to limit
the joint's movement to its normal boundaries, but when they are stretched
out too much, they cannot do that job properly. And since that angry
little muscle attached to the ball joint in front of the ear must
contract to open the jaw, it may cramp when opening the mouth wide pulling
the ball too far forward. Thus, people with these habits are
prone to dislocating their jaws when opening wide to take a bite
of a large sandwich like a grinder ("submarine sandwich" for those who live
in New England).
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Ankylosis of the
joint: In very extreme cases
of the disorder, long term abuse of the joints can cause the separate bones
to fuse together. This is most usually due to severe bruxing, or as a
response to severe joint trauma. The technical term for this is ankylosis, and it may severely limit the patient's ability to open the
mouth at all. This is a VERY rare occurrence. In 29 years of
practice, I have never seen such a case, but the existence of this
phenomenon shows just how serious this disease can become.
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Vertigo (dizziness) and Tinnitus
(ringing in the ears) can be associated with severe cases of TMD.
There are a number of competing theories explaining why TMD may cause
these symptoms. Both vertigo and tinnitus are associated with
structures in the inner ear.
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The first theory involves inflammation of the joint capsule
which spreads to adjoining areas in the skull, including the structures in
the inner ear. This would include the vestibular organ which
contains the semicircular canals. Fluid movement in these canals
responds to movements of the head, and provides the sense of balance.
Disease processes in this organ would cause vertigo (dizziness). The
second major organ in the inner ear is the cochlea which is
responsible for converting the vibrations in the air to nerve impulses that
can be perceived by the brain. Disease processes affecting the
cochlea, including inflammation, would cause hearing loss and tinnitus.
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A second theory posits that pressure on the
temperomandibular joint not only injures the joint, but allows the damaged
joint itself to place pressure on nerves and blood vessels that supply
the structures in the inner ear. Constrictions in these nerves and
vessels would presumably have negative effects on the inner ear structures
they service.
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A third theory involves two tiny muscles, the tensor veli
palantini and the tensor tympani, which function in the middle ear.
The tensor veli palatini constricts and dilates the eustachian tube
which in turn is responsible for equalizing the air pressure on either side
of the tympanic membrane (the eardrum). This is the muscle that
functions when you "pop" your ears. The tensor tympani
attaches directly to the eardrum and helps to
protect the inner ear by dampening vibrations within it. The nerves
that supply these muscles are closely associated with the nerves that supply
the medial and lateral pterygoid muscles. These are chewing muscles
and are highly active when the patient is bruxing (grinding) the teeth.
The theory is that spasm in the chewing muscles due to TMD causes spasm of
these two tiny "ear muscles" which in turn affects the semicircular canals
and the cochlea causing dizziness and tinnitus. This
theory seems unlikely since both muscles function on structures in the
middle ear and do not impinge directly on the inner ear where the organs
responsible for balance and hearing actually reside.
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A fourth theory, and the one that most experts are leaning
toward right now , involves the reflexive contraction of the
sternocleidomastoid
muscles (SCM) when patients clench their teeth. It has been shown that
pressure on certain trigger points in the SCM can trigger vertigo, although
the reasons for this are not exactly clear. It has also been shown
that when subjects clench their teeth,
the SCM will also contract.
It is hypothesized that chronic tension in this muscle triggers periodic
episodes of vertigo, along with headaches and neck aches.
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Vertigo associated with TMD is a fairly rare symptom.
If you have a problem with chronic dizziness and think it may be due to
temperomandibular dysfunction, you need to ask yourself if you have at least
some of the symptoms listed above, especially
chronic jaw soreness,
headaches,
ear aches,
neck aches,
clicking joints,
chronic jaw dislocation
and/or an inability to open
the Jaws wide. Some evidence exists that the vertigo may
occur in the absence of these symptoms, but in a majority of cases, the more
obvious symptoms of TMD precede the vertigo.
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Tinnitus, on the other hand, is a common disorder and is
frequently associated with severe TMD. People who have learned to live
with all the other symptoms of TMD may finally seek treatment for the
tinnitus, not realizing that the other craniomandibular symptoms are part of
the same syndrome.
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Oral surgical
complications: If a
bruxer
has a tooth extracted, he WILL almost certainly get a
dry socket.
In general, bruxers are subject to more severe and prolonged pain after any
oral surgical procedure.
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Periodontal disease:If a patient who bruxes
does not clean his teeth thoroughly, his
periodontal disease will progress much
faster than those who do not brux. Periodontal disease does not happen
because a person bruxes or has the symptoms of TMJ. However, bruxing
is a codestructive factor causing more severe and faster progressing bone
loss due to preexisting periodontal disease. Periodontal disease is
caused by poor oral hygiene.
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Recurrent decay: If a bruxer has a
sugar habit, he will tend to get more
recurrent decay under his fillings or other restorations than someone who
does not brux. The mechanism here is that the constant pressure on the
fillings causes tiny micro cracking in the tooth structure underneath the
fillings, thus allowing sugar and bacteria to seep under them.
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Phantom tooth
pain: TMD patients
frequently present at dental offices with pain that mimics the pain of a
dead or dying nerve. When a tooth has symptoms that suggest it needs a
root canal,
but shows no testable signs of needing one, we say that the tooth is
suffering phantom pain. In many cases, the pain is really
caused by the nervous habit of grinding on that tooth to the exclusion of
others. More unnecessary root canal procedures are performed on
otherwise healthy teeth for this reason than any other. Often, the
only treatment necessary to relieve the pain is to occlusally adjust the
tooth, which means to change its shape so it cannot contact the opposing
teeth in the opposite arch.
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Root canal complications: If it really becomes necessary for a
dentist to perform a
root canal on a tooth (for any reason),
patients who display the symptoms of TMD generally have a really miserable
time with pain between visits. Root canals (endodontic treatment)
generally proceed without much pain from beginning to end for most patients.
But persons who unconsciously grind and clench their teeth tend to cause
themselves severe, prolonged pain which is really the result of the bruxing
habit and only secondarily due to the endodontic procedure itself.
This is well explained on my page concerning root
canals.
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Denture
Sores: Denture
patients who have bruxing and clenching habits get constant denture sores,
and sometimes cannot even wear their dentures, no matter how well they fit.
Each time the dentist removes one denture sore, another crops up.
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Cracked teeth: Various
categories of
Cracked tooth syndrome can be caused
by the pressure of bruxing. Cracked teeth do not appear to be broken
or decayed, but cause sharp pain when pressure is applied to them.
Cracked teeth are serious problems because the long term prognosis for these
teeth is not always good.
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Cold
sensitive teeth: Constant pressure on the teeth due to bruxing puts
pressure on the
periodontal ligament surrounding the
root of the tooth. This affects the nerves causing the teeth to
become extremely sensitive to cold. It is probably the most common reason for
severe tooth sensitivity.
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Attrition: Serious bruxing causes
attrition of the teeth. Attrition is the
simple wearing down of the tops of the back teeth and the top edges of the
front teeth. This can become very pronounced in older people who have
stressful occupations, or men who do a lot of heavy lifting. It can
also be quite serious among
ravers who make extensive use of Ecstasy
and methamphetamines.
In the image to the left the cusps of the molars have been worn down
exposing the yellow dentin underneath. The image on the right
shows how serious attrition can be. This is a 76 year old man who has
been bruxing all his life. Click on this image to see it full size.
Abfraction:
The theory of abfraction is controversial. Dentists
began noticing eroded or notched areas (erosions) on teeth close to the gum
line (this is called the cervix of the tooth) as early as the early
1700's. The origin of these tooth defects remained a mystery for 150
years until a dentist named W.D. Miller did some research and published a
paper in 1907 titled: Experiments and observations on the wasting of
tooth tissue variously designated as erosion, abrasion, chemical abrasion,
denudation, etc. His conclusions were based on both observation
and experiment. He concluded that these notch-like cervical erosions
were caused by vigorous tooth brushing in combination with abrasive tooth
powders.
Interestingly,
GV Black, who is widely considered the
father of modern dentistry disagreed with Miller, and even traveled to
England to see his work. Black had to agree that many of Millers
experimentally produced lesions looked like the erosions he had been
studying, but remained skeptical. Black eventually published a paper,
based on observation alone refuting Miller's conclusions.
Unfortunately, Miller died before he could respond to Black's paper, and the
origin of cervical erosions has remained controversial ever since.
 In
the early 1990's, a dentist named J. O. Grippo concluded that cervical
erosions were the result of flexing of the teeth at the gum line due to heavy
bruxing (grinding). This flexure resulted in damage to the enamel rods
at the gum line resulting in their loosening and consequent flaking away of
the tooth structure. He named this type of damage abfraction in
a paper published in 1991 (Grippo JO. Abfractions: a new classificationof
hard tissue lesions of teeth. J EsthetDent 1991; 3:14-19.)
The theory of abfraction
The theory of abfraction postulates that very hard
bruxing forces
on the occlusion causes the teeth to deform and bend on a microscopic level.
Nearly all the research on the relationship of occlusal forces (bruxing)
to cervical lesions shows that teeth do, indeed flex in the cervical region
under bruxing loads, but none seems to cite actual damage
caused by this deformation without an abrasive or erosive component
applied as well. Nevertheless, the abfraction theory argues
that bruxing forces alone can cause an erosion of the
enamel that protects the teeth on the buccal surface , near the gum line.
It is postulated that abfraction is responsible for chronic sensitivity of the teeth to cold
foods and liquids. This biomechanical theory implies that damage like that seen in the images below
would be
difficult to repair with bonded fillings because the repair would tend to pop off after
a while due to the constant deformation of the tooth caused by bruxing.
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Many dentists dispute the theory of abfraction, blaming this type of damage
on what is commonly called "toothbrush abrasion". This harks back to
the early work of W.D. Miller in 1917, however it has been confirmed by more
recent studies by
T.C. Abrahamsen which have shown that toothpaste
(not the toothbrush) is abrasive enough to cause this type of damage if the
patient is too aggressive in brushing the teeth in a very hard and vigorous
"sawing" motion. Abrahamson suggests that the term "toothbrush
abrasion" be replaced with the term "toothpaste abuse". His
studies using mechanical "tooth brushing" machines have shown that the
toothbrush alone does not cause the type of tooth damage shown here, but the
addition of toothpaste to the bristles does! (Toothbrushs without
toothpaste do cause soft tissue damage and indeed, overly vigorous
toothbrushing without toothpaste leads to gingival recession.) The current support
for the theory of abfraction, as opposed to theory of toothbrush abrasion
may be
due, at least in small measure to the considerable influence of toothpaste
manufacturers who actually did much of the original work showing the damage that
toothpaste could do to teeth, but suppressed the results for obvious
reasons.
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Dental Thermal Hypersensitivity
Proponents of the theory of abfraction postulate that dental
hypersensitivity to cold is due to abfractive removal of tooth structure
at the cervix of the tooth due to bruxing. Opponents would argue that most dental thermal
hypersensitivity is due to erosion of tooth structure because of
toothpaste abuse. |
The evidence against the theory of abfraction is as follows:
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The theory of abfraction is based primarily on engineering
analyses that demonstrate theoretical stress concentration at
the cervical areas of teeth. While there are a number of studies
linking occlusal forces to tooth flexure,
few controlled studies exist that demonstrate the relationship between occlusal loading and abfraction lesions.
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Most of the damage of this nature is to the buccal (cheek
and lip) surfaces of the teeth, with little erosion to lingual (tongue) surfaces.
If flexure of the teeth were causing this problem, it seems likely that we
would see equal damage to both buccal and lingual surfaces.
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There is little or no evidence of these lesions in
prehistoric skulls, even though the teeth show considerable occlusal
(chewing surface) wear from mulling tough and fibrous foods. All the
cervical erosions found in historic skulls seem to begin after the
invention of tooth powders and toothbrushes.
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The lesions tend to be much worse on the buccal surfaces of
the premolars and the canines where patients are likely to place the most
brushing force. It becomes progressively worse as one proceeds from
the posterior teeth to the anteriors. Furthermore, the worst affected
teeth tend to be in buccal version. The teeth in which linguals are affected
are mostly found mesial to (in front of) an edentulous space (like the one shown
in the image below).
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The damage seems to stop at the gingival crest instead of at
the crest of the bone, which is where the theory of abfraction suggests the
flexure should be the worst. The gingiva heal daily protecting the
root of the teeth from the toothbrush and toothpaste, and these lesions DO
show a sharp delineation at the gingiva with a sloping finish in the coronal
direction.
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Not all persons with cervical lesions demonstrate occlusal
wear, which would indicate a bruxing habit, and not all persons with severe
bruxing occlusal wear exhibit cervical non carious lesions.
 The theory of abfraction postulates that toothbrush
abrasion works in combination with bruxing to create
some fairly bizarre effects on teeth. The image on the right
shows a tooth which has assumed the shape of a Coca Cola bottle. You are viewing the back of the
tooth in a mirror. Click the image to enlarge it. The yellow
arrow emphasizes the area of concern. On
the enlarged image, you
can see that the damage stops at the gum line, leaving a shelf of
unaffected root about even with the level of the gums.
On the other hand, the fact
that this tooth is the last in the arch makes it more vulnerable to
abrasion by the toothpaste on toothbrush bristles, as it does not have
another tooth behind it to "protect" it. Dentists who do not believe in
the theory of abfraction argue that natural tooth
structure is simply abraded away by overzealous tooth brushing. The image below
shows a similar 270 degree lesion surrounding both central incisors.
The lingual (tongue side) of the teeth are not affected as severely as
the buccal (front) and interproximal (between the teeth) areas where
vigorous brushing would most likely take place. |
 
Both of these images represent the type of cervical
erosions under discussion. Those dentists who subscribe to the
theory of abfraction believe that patients with these lesions are
probably severe bruxers as well as "severe tooth brushers".
Click on either image to see enlargements.
For those who believe in the theory of abfraction
and wish to read more about it (with numerous images), you should see the site of
Dr. Brian Palmer, and click on the
three sections of his long, well illustrated presentation.
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 Meth
mouth
Bruxing is also a major problem for meth addicts. Click on
this image for more. |
The TMJ section used to occupy a single page on this website,
but due to its extreme length, it has been broken up into seven separate pages.
A good understanding of the Temperomandibular joint, occlusion and their
associated disorders may be gained by reading them in order.
Next page==>TMD
and its association with other
problems
TMJ Pages
1,
2,
3,
4,
5,
6,
7
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