Prolonged retention is usually needed in:

 # Prolonged retention is usually needed in:

A. Diastema

B. Mild crowding

C. Anterior cross bite

D. Deep bite

The correct answer is A. Diastema.

Fixed (bonded) orthodontic retainers are normally used where intra-arch instability is anticipated and prolonged retention is planned. There are three major indications:

• Maintenance of lower incisor position during late growth

• Diastema maintenance

• Maintenance of posterior tooth position in adults

Reference: Proffit's Contemporary Orthodontics, 6th Edition.