John C. Chao, DDS

Research Associate Professor, University at Buffalo, SUNY
Adjunct Assistant Professor, Ostrow School of Dentistry, USC

(626) 308-9104

News & Press



John C. Chao, D.D.S., M.A.G.D
Anxiety Management,
Behavior Science,
Faculty, USC School of Dentistry

Chipping of Front Teeth may Be Caused By Nerves

Debbie (not her real name) used to get a lot of compliments for her smile. Now her front teeth have chipped so badly that she doesn't want to smile any more. In addition her teeth have been especially sensitive to anything cold, sometimes even cold air. Her cousin was getting married in two weeks and she really wanted her front teeth restored to their original condition for the occasion. She seemed puzzled as to why her teeth have deteriorated so much.

Upon examination it was evident that the jagged edges of Debbie's decay-free upper front teeth fit perfectly with the chipped and broken lower front teeth. There was only one explanation for such a perfect fit. Debbie has been habitually doodling with or clenching her front teeth. At first Debbie denied ever having such a habit. But upon reflection, Debbie realized that she had indeed been unconsciously rubbing her front teeth together whenever she feels tense or nervous. In fact she recalls that she sometimes wakes up in the morning with her jaws feeling stiff and tight, especially when she feels stressed or fatigued the night before.

Like Debbie, millions of people have the unconscious habit of grinding their teeth, especially at night. Dentists called this habit "bruxism." Bruxism is silent and deadly to teeth and gums. Research has shown that up to two thousand pounds of force per square inch can be generated by clenching or grinding. No wonder teeth chip, crack and get sensitive to cold stimuli. Millions of teeth are crowned or otherwise restored because of this problem. But what many people also do not realize is that clenching or grinding may in part cause gum recession. When we clench the forces of mastication can cause the roots of the teeth to minutely flex. This repeated flexing leads to erosion of bone and gum around the roots of the teeth. This phenomenon is called "flosure" erosion. Notching of the roots at the gum line is attributable to clenching and nighttime grinding. Of course vigorous over-brushing of the teeth will further aggravate the problem. Extreme sensitivity of the teeth to ice or cold drinks or food is very often associated with bruxism. Flexing of the teeth traumatizes the pulp (nerve tissue) of the tooth and interferes with circulation to the canals in the roots. This happens in the absence of cavities. So if there is no evidence of deep decay in the teeth, you should always suspect bruxism as a cause of cold sensitivity.

Bruxism is most often associated with stress. But there are many other causal factors related to bruxism. Malocclusion (abnormal bite relationship), especially the kind where there is too much "overbite," is often named as a cause of bruxism. Other causes including chronic pain, mouth breathing, snoring, certain kinds of anti-depressants and temporo-mandibular (jaw) joint disorders.

Treatment for bruxism is preceded by a thorough clinical evaluation by your dentist for the causes of the condition. If bruxism is primarily a response to stress, obviously any stress reduction efforts or program needs to be considered. To further alleviate stress-induced bruxism, many kinds of "night guards" are available, depending on the nature of the problem. A night guard is shaped somewhat like an orthodontic retainer and is difficult to get used to. Where your dentist has determined that bruxism is only a transient problem, a temporary, soft night guard may be used. But if the bruxism habit is entrenched and difficult to break, a custom-designed "night-guard" can be made that can help train the patient not to grind. This may require multiple visits to the dentist for training purposes and bite adjustment of the appliance. For obvious reasons it is generally recommended that all restorative and gum treatment be completed before a night guard is placed.

In Debbie's case her smile was restored with life-like veneers (porcelain shells bonded to the front of her teeth) and a night guard was made to protect the teeth from further chipping and cracking. Her night guard has helped her become much more aware of bruxism and she no longer wakes up with stiffness and soreness in the jaws. She received many compliments at the wedding for her bright smile, and she thoroughly enjoyed the event.


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