The study compares the rate of en-masse retraction using 0.018-inch versus 0.022-inch slot orthodontic bracket systems in adult patients with maxillary dentoalveolar protrusion.

• Proper examination of the oral structures is needed to identify caries, fracture or missing teeth.
• Full set of records ( study models, lateral cephalometric radiographs, photos) will be taken for every patient as part of the routine procedure for treatment of patients in the outpatient clinic of the Orthodontic Department, Cairo University.
• In intervention group: Bonding of upper and lower arches including 2nd maxillary molars with bracket prescription Roth 0.018-inch (American Orthodontics).
• In comparator group: Bonding of upper and lower arches including 2nd maxillary molars with bracket prescription Roth 0.022-inch (American Orthodontics).
• Levelling and alignment in both groups with wire sequence: Ni-Ti (0.014,0.016, 0.016×0.022)
• Steel ligation of maxillary (2nd premolar, 1st molar and 2nd molar) for anchorage.
• Extraction of maxillary 1st premolars.
• Impression will be taken, poured in plaster from which digital models will be fabricated before beginning of en-masse retraction (the baseline model).
• Lateral cephalometric and periapical radiographs will be taken before starting retraction.
• En-masse retraction will be done using 0.017x0.025 TMA T-Loop10 in both groups, the loops will be reactivated monthly.
• Alginate impressions will be taken every month, that will be scanned to obtain digital models to assess the rate of retraction for 6 months.
• After 6 months, last obtained digital model will be evaluated for assessment of anchorage loss, and Lateral cephalometric and periapical radiographs will be taken to assess changes in the anterior teeth inclinations and apical root resorption respectively.
• The patients' treatment will be completed as indicated for them.

Inclusion Criteria:

• Maxillary dentoalveolar protrusion cases that require upper first premolars extraction.
• Full permanent dentition (not necessitating third molars).
• Good oral hygiene.

Exclusion Criteria:

• Patients having systemic diseases or on medications that would affect tooth movement.
• Active periodontal disease or obvious bone loss in maxillary arch.
• Patients with habits that are detrimental to dental occlusion (thumb sucking, tongue thrusting).
• Previous orthodontic treatment.
• Missing teeth.