Spacing, the opposite of crowding, is an excess of space between permanent teeth. It occurs when there is a disharmony in the tooth to jaw size relationship and can be caused by impacted or missing teeth, protrusive teeth, thumbsucking, and aberrant swallowing patterns.

Spacing should be treated because it can result in the improper functioning of teeth due to an improper bite, food packing problems, etc.. Also, many patients and parents do not like the aesthetics of spaces between teeth.