This study aims to evaluate the efficiency of direct 3D printed aligners in achieving the crown movement of upper and lower incisors in patients with spacing during space closure and to compare them with the predicted tooth movements

This study will be carried out on 23 patients seeking orthodontic treatment at the outpatient orthodontic clinics at the Faculty of Dentistry, Suez Canal, Beni Suef, and British Universities.

The inclusion criteria are: patients aged 18-45 years, with full permanent dentition (excluding third molars), generalized spacing or spacing between anterior teeth, normal skeletal relationships, and Angle Class I or mild Class II malocclusions. Patients with the following criteria will be excluded: patients with missing or extracted permanent teeth (excluding third molars), periodontally compromised teeth, who need any form of hybrid orthodontic treatment (a fixed appliance with aligners), any signs or symptoms of temporomandibular disorders, severe Angle Class II or Class III malocclusions, crowding, and Class II or Class III skeletal discrepancy.

Methods:

1. Intraoral scans will be obtained for the upper and lower arches followed by a 3D simulation before treatment to check the biomechanics and movements of the treatment.
2. After setting up the 3D digital design for treatment, we will begin the fabrication of 3D printed aligners.
3. The patient will be instructed to use the aligner, and instructions will be given to the patient to put aligners in warm water before wearing them. This activates their shape memory allowing them to fit more easily and comfortably, thus reducing stress on the aligners.
4. The Patient will change the aligners every week according to the manufacturer's instructions and at the end of treatment, a new 3D scanning for the patient's dental arches will be taken to obtain the actual model after treatment.
5. The virtual pre-treatment model obtained before, and the actual post-treatment model will be exported as STL files and imported into digital software as virtual pre-treatment and actual post-treatment models.
6. The virtual pre-treatment, virtual and achieved post-treatment models will be superimposed digitally.
7. After superimposition, a 3D coordinate system will be generated for tooth movement measurements. After determining the reference points on the pre-treatment model, they will be transferred onto actual and virtual post-treatment models through tooth crown surface superimposition. The achieved and predicted changes in crown movement of the upper and lower incisors will be calculated.

All numerical data will be collected for statistical analysis.

Inclusion Criteria:

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

Exclusion Criteria:

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