Diastema refers to a gap or space between the teeth. This gap is caused because of an unequal relationship between the jaw and the size of patients teeth. These spaces can form anywhere in the mouth, but are most common between the upper two front teeth. This condition affects both adults and children. In fact, this condition is more common in children, but gaps may disappear once their permanent teeth grow in. In adults however, diastema will not resolve itself on its own.