Bruxism (Nightgrinding)

Signs & Symptoms


The term bruxism is defined as: “to grind the teeth, a clenching of the teeth, associated with forceful jaw movements, resulting in rubbing, gritting, or grinding together of the teeth, usually during sleep.”

What causes bruxing to occur?

This is a very difficult question to answer. Some researchers say that if the occlusion (bite) of someone is not correct they will brux. Others say that it is a central nervous system disorder. Others say it is a multifaceted problem.

For all practical purposes……EVERYONE bruxes. Therefore, the question is NOT whether a person does in fact brux. Rather, the better question is to what degree do they brux. There is not a scale of bruxing that exists, but, we could imagine that there is such a scale. This scale could run from a 1 indicating a very very slight habit to a 10+ which would indicate a severe bruxer. A person at level 1 would not show any signs of bruxing at all. On the other hand the people in the higher end on the scale would show one or several signs. The pressure that can be generated across the teeth can range from 100 to 600psi (pounds per square inch) this is an incredible amount of force. The problems outlined below occur as a result of these forces being applied over many years - slowly - and it can be difficult to recognize the cause/effect sequence.

Stress - As with so many things in life, stress is a very large factor. In the paragraph above, in regards to the scale of bruxing, people stressed will often dial up the level of bruxing and develop temporary symptoms (cold sensitivity the most common) that decrease after the stressful episode ends.

Possible signs, complications or damage that may occur are:

1. Wearing of teeth.
Wear occurs from the movement of the teeth harshly against one another. Although all teeth may show this type wear, it is especially noticeable when a person has front teeth that appear having the same length - as if they were filed down.

2. Breaking of teeth.
As teeth wear, the edges of front teeth and the cusps or corners of back teeth will begin to show microfractures or cracks. These cracks can not be seen on x-rays. It takes magnified vision and/or an intraoral magnified image to diagnose them. Where this becomes especially important, is that teeth with these type of fractures will either eventually chip, break a corner, or yet require root canal therapy. The reason for root canal therapy is that the fracture begins on the surface of the tooth and eventually deepens until the crack enters the area of the nerve.

3. Sensitive teeth.
Usually a generalized soreness and/or a cold sensitivity.

4. Receeding gums and/or teeth with gum line “notches”.

Most people have been told or assume that receeding gums occur because of age, using a hard bristle brush or the occurence of gum (periodontal) disease. In fact none of these reasons are correct in a majority of the cases. These are referred to as abrasion areas. When teeth grind hard against each other year after year, they flex at the gum line and the enamel (which ends thinly at the gum line) microfractures away. The end result is an area at the gum line that you can catch your fingernail in and may get extremely sensitive to touch and/or cold.

In this picture, there is exposed root surface and advanced abrasion areas.



5. Loose teeth.
Teeth loosen because of the "rocking" back forth that occurs. The best analogy is the example of getting a fence post out of the ground by rocking it back and forth.

6. Periodontal pockets (loss of supporting bone around the teeth).
Sometimes instead of the tooth getting loose, there may be a generalized horizontal loss of supporting bone and/or localized areas of bone loss.

7. Bony ridges (tori).
Instead of losing bone support - some people actually form "extra" bone to support the teeth (this appears as bony ridges that can be seen and felt on the jaw bones as a smooth raised area about at the level of the roots.

The image on the left is of the lower jaw showing extra bone in the "floor" of the mouth by the tongue. On the right, the picture shows the cheeks pulled back and the ridge along and above the upper back teeth.

8. Cheek irritation.
A ridge or line of fibrosed (toughened) tissue on the inside of the cheek that corresponds to where the teeth come together. Sometimes a person will actually bite themselves along this line (especially in the most posterior molar area).

9. Sore muscles (especially in the cheek and temple area).
When these two muscles are overused. They may get sore - just like when you over exercise, your other muscles get sore.

10. Headaches (especially upon waking in the same muscle areas mentioned above).
Instead of soreness, the muscle aches will appear as a headache.

11. TMJ Problems (jaw joint pain / soreness / etc).
The jaw joint may be over loaded and resulting problems occur.

These signs take time (usually decades of years) to show themselves.

Does everyone show every problem? No they don't, we are all very different. Some of us will exhibit none of these problems (thank your genetic code for that), some of us will exhibit severe problems (curse your genetic code for that). So any combination, or NO problems may exist for any one person.

So, what should anyone do about bruxism?
Is there a cure?

This is a very difficult thing to answer. For a large number of people, the problem is that their bite is off - this triggers through a series of physiological signals, a dramatic increase in the amount of bruxing.


It would be logical to think that an acrylic nightguard is simply a piece of plastic used to cover and prevent the teeth from coming together while sleeping at night. This is true - BUT - most importantly, when in place it provides a correct bite so that muscles will relax and problems in a persons bite will not trigger the bruxing action.. The aspect of making and delivering a nightguard CORRECTLY is difficult to explain but you may see this process by clicking here. A point needs to be made that tooth wear still slowly occurs when using a nightguard. The reason for this is that a person (especially severe bruxers) will clench and very slightly grind during the day time when their guard is not being worn.

A nightguard is NOT a solution, rather a method of greatly decreasing the damage caused by bruxing. It is possible to alter a bite so that a guard may not be needed - the method varies from case to case.

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Dr. Maury Hafernik
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Austin, Texas 78759
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