Class III Malocclusion Treated with an Orthopedic Protraction Face Mask During Mixed Dentition, Followed by Invisalign Aligners to Correct Anterior Crossbite Occurring after Relapse During Adolescence

An eight-year-old male patient presented with a class III malocclusion on a skeletal class III pattern with an average lower face height, an anterior crossbite, slightly anterior lower crowding, and good oral hygiene; the parents were concerned about his crossbite. The aim of treatment was to correct the anteroposterior discrepancy by using a face mask during the 12-month mixed dentition period, during which the patient achieved a good result. However, after seven years of retention, the patient presented an anterior crossbite with a skeletal class I pattern and an average lower face height. He decided to wear clear aligners for treatment; 28 sets of clear aligners, which were changed every two weeks for twelve months, were necessary to achieve anterior crossbite correction.