A diastema is a gap between the teeth. It is not harmful, and it appears in children and adults. In children, the gap typically closes when their permanent teeth come through.

A diastema is a gap between teeth that is wider than 0.5 millimeters. It can develop between any teeth.

Treatment is not usually necessary for medical reasons. But if a person dislikes the appearance of their diastema, it is possible to close or narrow the gap.

If a person’s teeth are too small, relative to the size of their jawbone, gaps may develop between the teeth.

Jawbone and tooth sizes can be genetic, which is one reason that diastemas can run in families.

If some teeth are missing or smaller than others, a diastema can develop.

This often involves the upper lateral incisors — the teeth to either side of the two upper front teeth. If the upper lateral incisors are missing or relatively small, a gap can develop between the two front teeth.

The labial frenum is the tissue that extends from the inside of the upper lip to the gum above the upper front teeth.

If this tissue is especially large, it can cause a gap to form between these teeth.