Leeway space and the resolution of crowding in the mixed dentition.

The leeway space provides adequate space to resolve crowding that is present in the mixed dentition in the majority of individuals. This space can be maintained by preserving arch length with a lingual arch as the primary teeth begin to exfoliate, unless conditions such as the premature loss of a primary canine require earlier intervention. A lip bumper can also be inserted after the eruption of the first premolars to preserve arch length.