The aim of the study is to compare apical root resorption accompanied orthodontic treatment using clear aligners vs fixed appliances.

by using pretreatment and posttreatment CBCT, root resorption will be measured using a 3D imaging software.

Inclusion Criteria:

• Healthy systemic condition/no systemic illness, as reported by patients.
• No use any form of anti - inflammatory drugs the at beginning of study.
• Good oral hygiene.
• Cooperative and motivated.
• In the permanent dentition with all teeth present ( except third molars).
• Minimum to moderate anterior crowding.
• No previous orthodontic treatment.

Exclusion Criteria:

• Previous upper removable orthodontic treatment.
• Patients who required surgery to correct skeletal discrepancies.
• Patients with hyperdontia, hypodontia, or syndromic diseases (e.g. cleft lip and palate).
• Uncooperative patients.
• Patients with poor oral hygiene.