Yellow teeth, gum disease and tooth loss may conjure up images of aging, yet many people are unaware that as they age, they are more likely to develop crown crazes – unsightly hairline cracks in tooth enamel.

"Crown craze candidates are usually in their mid-thirties," says Academy of General Dentistry spokesperson Barbara A. Rich, DDS, FAGD. "Years of wear and tear and bad chewing habits create extra pressure and cause crazes to form, especially in teeth with older, large fillings."

This condition develops over time to all teeth, but crazes are more apparent on the front upper teeth, where staining is more likely, and shows up as a thin brown line.

"It's not just a cosmetic problem," warns Dr. Rich. If the craze is deep enough in the enamel, the tooth may develop some sensitivity.

To avoid developing crazes that may instigate dental accidents, Dr. Rich advises her patients to stop chewing on popcorn kernels, hard candy or ice cubes. "It's quite common to develop a craze when repeatedly chewing hard objects."

Many patients are not aware of this problem until their dentist points it out with a mirror or intraoral camera, says Dr. Rich.

If a craze does not cause discomfort or pain, your dentist will monitor the tooth at each dental visit and have you keep a watchful eye on the tooth and report changes. If the crack goes to the inner surface of the tooth, you may want to consider a crown in order to restore tooth strength.