INTELIHEALTH - Many people get their wisdom teeth removed as teenagers. Others wait until adulthood. A study of more than 4,000 adults looked at which adults were most likely to have problems after this surgery. Wisdom teeth also are known as third molars.

Researchers from the Harvard School of Dental Medicine did the study. The average age of people in the study was 40.

Infection and dry socket are the most common problems that occur after wisdom tooth removal. In dry socket, the blood clot falls out of the hole where the tooth used to be. Dry socket is painful and can last for weeks.

Some people in the study had impacted wisdom teeth or partially impacted wisdom teeth. An impacted tooth is under the gum and bone and cannot come in properly.

People with impacted wisdom teeth were up to six times as likely to have infection and dry socket after surgery as people who had wisdom teeth that already had come in. Those with bone-impacted teeth were the most likely to have infections or dry socket after surgery.

People who had an infection around their wisdom teeth before surgery were more likely to have an infection after surgery. People who had other things wrong with their wisdom teeth (such as cavities) were three times as likely to have infection or dry socket afterward.

Wisdom teeth are easier to remove in younger people, and recovery is faster. For most people, the wisdom teeth do not cause problems and do not need extraction. In people with no symptoms, an oral surgeon will weigh risks and benefits before deciding on surgery.

The study appears in the November issue of the Journal of Oral and Maxillofacial Surgery.