Table of Contents
- 1 The Signs and symptoms of Temperomandibular Joint Syndrome
- 1.0.1 The trials and tribulations of TMD patients
- 22.214.171.124 Headaches, earaches and neck aches:
- 126.96.36.199 Headaches
- 188.8.131.52 Neck aches (and headaches)
- 184.108.40.206 Earaches
- 220.127.116.11 Sore jaws and teeth upon waking in the morning:
- 18.104.22.168 Clicking and popping TM joints:
- 22.214.171.124 Difficulty opening the mouth, or remaining open at the dentist’s:
- 126.96.36.199 Trismus:
- 188.8.131.52 Frequent jaw dislocation:
- 184.108.40.206 Ankylosis of the joint:
- 220.127.116.11 Vertigo (dizziness) and Tinnitus (ringing in the ears)
- 18.104.22.168 Oral surgical complications:
- 22.214.171.124 Periodontal disease:
- 126.96.36.199 Recurrent decay:
- 188.8.131.52 Phantom tooth pain:
- 184.108.40.206 Root canal complications:
- 220.127.116.11 Denture Sores:
- 18.104.22.168 Cracked teeth:
- 22.214.171.124 Cold sensitive teeth:
- 1.0.2 Attrition:
- 1.0.3 Abfraction
- 1.0.4 The theory of abfraction
- 1.0.1 The trials and tribulations of TMD patients
The Signs and symptoms of Temperomandibular Joint Syndrome
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!”
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.
Headaches are associated with muscular hyperactivity when clenching the teeth. Clenching is defined as placing the teeth together with heavy force without lateral (side to side) movement of the lower jaw. The chewing muscles involved in headaches are the temporalis muscle, the masseter and the medial pterygoid muscles. Click on
images above to see images full size. Overuse of several neck muscles have also been implicated in TMJ headaches (see below). The headaches associated with TMJ can be quite severe. They are similar to (and some say identical with) migraine headaches. They often happen at night while the patient is sleeping, but can happen at any time of the day.
Neck aching and headaches are due to hyperactivity in the sternocleido-mastoid muscles (SCM) and the trapeziusmuscles.
The SCM’s are strap like 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.
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 pages on occlusion.) The earaches may be closely associated with the headaches and also the toothaches caused by bruxing, spreading from one area to another. Upon occasion, the earaches are also accompanied by tinnitus, which is a high pitched ringing in the ear.
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 anti-snoring devices 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!
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)
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.)
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.
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).
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.
Vertigo and tinnitus 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.
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.
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.
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.
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.
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.
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 cranio-mandibular symptoms are part of the same syndrome.
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.
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.
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.
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.
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.
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.
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.
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. The image on below 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.
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 classification of 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.
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! (Toothbrushes without toothpaste do cause soft tissue damage and indeed, overly vigorous tooth brushing 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.
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:
The theory of abfraction is based primarily on engineering analyses that demonstrate theoretical stress concentration atthe 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.
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.
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.
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).
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.
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 above shows a tooth which has assumed the shape of a Coca Cola bottle. You are viewing the back of the tooth in a mirror. The yellow arrow emphasizes the area of concern. 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.
The image above represents 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”.
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.
Bruxing is also a major problem for meth addicts. Click on this image for more.