Class I, lack of space and anterior crossbite
Class I, anterior and posterior crossbite on the left side. Congenital absence of the lower right second premolar. Retention of the lower right primary second molar.
The treatment included a rapid palatal expansion phase, the extraction of the upper right second premolar, of the upper left first premolar and of the lower right primary second molar. There were no extractions of premolars on the lower left side.