This study aimed to evaluate clinical and radiographic outcome of regeneration in immature permanent human teeth using two different types of scaffolds:

1. Collagen-hydroxyapatite scaffold (Osteon III collagen) after blood clot.
2. Conventional blood clot scaffold.

Inclusion Criteria:

1. Single rooted immature permanent teeth.

2. Symptoms:

   1. Pulp necrosis either due to infection or trauma.
   2. Periapical condition; tooth should have periapical radiolucency.

3. Tooth should be restorable without the need for further post placement.

4. Age: from 6-15 years.

5. Sex: males or females.

6. Preoperative Cone beam Computed tomography is a must.

Exclusion Criteria:

• Teeth with complete root formation. 2. Teeth that are badly broken down with difficult isolation. 3. Medically compromised patients. 4. Periodontally affected teeth.