A major cause of concern for parents of growing children involves how the alignment of the permanent teeth is coming through?? This is a common query faced by the Pediatric Dentist. The erupting teeth are full sized, but the mouth they are trying to fit into is still growing. A particular concern for parents is the “Ugly Duckling” Stage.

This is a normal stage of dental development, usually between the ages of 7 and 12 years, preceding the eruption of the permanent canines. During this time period, when the permanent maxillary central incisors erupt they tend to flare laterally and are widely spread creating spaces (also known as ‘PHYSIOLOGIC MEDIAN DIASTEMA’) between the teeth. This stage of eruption is known as the ‘Ugly Duckling Stage’. This position of teeth at this stage is compared to that of an ugly look of a duckling and hence the name ‘Ugly Duckling Stage’. The term is directly borrowed from Hans Christian Andersen’s fictional fable of the same name.

It is caused when the upper central and lateral incisors are tipped laterally due to the crowding created by the unerupted canines. As the canines grow they push on the roots of the incisors producing the tipping and resultantly a midline space between the front teeth. The midline space is normally transitory and the incisors usually assume normal alignment when the upper canines erupt into position creating a pressure back the other way.

The Ugly Duckling Stage of development is a normal occurrence and requires no orthodontic treatment or cause for concern. Normal physiological space between the permanent maxillary central incisors is about 2mm. When larger spaces are present it may signify an underlying pathological condition, which would require additional investigation.

Counseling the child to let them know that this is a transient stage will help them deal with any negative emotional consequences of this phase of their development.