Comparison Between Clear Aligners and Traditional Fixed Appliances in the Treatment of Four-premolar-extraction Cases

Patients who have severe crowding that require four premolars extraction will be treated in this study. The efficacy of the clear aligners and vestibular fixed appliances will be assessed. The treatment result of these two different methods will be explored using the Peer Assessment Rating (PAR) in two different times (T0: Before treatment, T1: After treatment) and the American Board of Orthodontics Objective Grading System (ABO-OGS) after treatment (T1). There are two groups: First group (Experimental): the patients in this group will be treated using clear aligners. Second group (Control): the patients in this group will be treated using fixed appliances.