**2. Definition and epidemiology of diastemas**

At the beginning of the last century, Angle [1] described median diastema as a common form of malocclusion where there is a space between the upper central incisors and, very rarely, between the lower central incisors. According to the author, the width of this space usually varies from 1 to 4 mm and always presents an unpleasant appearance, and may interfere with speech, depending on the width. Later, according to Bishara [2], diastemas were described as just clinically visible spaces between two or more adjacent teeth.

In publishing the Six Keys for normal occlusion, Andrews [3] stated in Key V that there must be fair points of contact throughout the dental arch, in the absence of dental size discrepancy. According to this information, diastemas are also considered a malocclusion by Andrews.
