This study aims to three-dimensionally evaluate the efficiency of direct 3D printed aligners in achieving the planned root torque by using CBCT and to assess the associated bone thickness changes and root resorption.

Participants will be recruited from the Faculty of Dentistry, Beni Suef, Suez Canal, and British Universities. All subjects will be informed of the treatment procedures and will sign a consent form.

the minimum total required sample size (n) was found to be (14) cases. The sample size was calculated using R statistical analysis software version 4.5.0 for Windows[11].

Methodology:

• Cone beam computed tomography scans will be done before treatment (T0).
• Intraoral scanning of the patients will be performed by using an intraoral scanner to obtain pre-treatment digital models of the upper and lower arches. The treatment plan will be set up, and the aligners will be 3D printed.
• The patient will be instructed to immerse the aligners in warm water before inserting them into the mouth to soften them and improve their fit. The patient will be instructed to change the aligners every week.
• At the end of orthodontic treatment (within 9 months - 2 years after the beginning of the treatment), a post-treatment CBCT scan will be obtained (T1)
• The achieved torque movement of the upper and lower incisors will be calculated by evaluated the pre and post CBCT scans taking the difference between T0 and T1.
• The difference between achieved and predicted torque movement (DAPM) will be obtained, and the efficiency will be calculated by dividing the achieved movement / predicted movement X 100 %
• The labial and palatal bone thickness and root length of the upper and lower incisors will be measured at T0 and T1 by using the pre and post cone-beam computed tomography, and the difference will be calculated.

The results will be obtained and statistically analyzed.

Inclusion Criteria:

1. Age: 18- 45 years old.
2. Non- extraction treatment.
3. Angle Class I or Class II dental malocclusion with generalized or localized anterior spacing.
4. Normal probing depth.

Exclusion Criteria:

1. Active periodontal disease.
2. Crowding cases.
3. Systemic diseases or medications that alter bone metabolism or tooth movement.