The goal of this clinical trial is to evaluate if regenerative endodontic treatment using two different forms of demineralized dentin matrix (DDM) can effectively treat immature permanent single-rooted teeth compared to treatment using RetroMTA in patients aged 9 to 15 years. The main questions it aims to answer are:

Does the use of DDM improve clinical and radiographic outcomes such as root length, dentinal wall thickness, and apex closure?

Is DDM a viable bioactive alternative to RetroMTA as a coronal sealing material in regenerative endodontic procedures?

Researchers will compare three groups: one using RetroMTA, one using a DDM-TheraCal LC mixture, and one using TDM-Hydrogel, to see if these materials differ in their effects on regenerative outcomes.

Participants will:

Undergo two treatment visits including canal disinfection, induction of bleeding to form a blood clot scaffold,

Receive placement of one of the study materials over the blood clot as a coronal barrier,

Have clinical examinations and CBCT imaging at baseline and multiple follow-ups up to 12 months to assess treatment success through signs, symptoms, and radiographic changes.

The study was conducted as a split-mouth randomized clinical trial, approved by research ethics committee, Faculty of Dentistry, Kafrelsheikh University, and carried out at Endodontic Department, Faculty of Dentistry, Kafrelsheikh University. 36 patients of both sexes aged from 9 to 15 years old were selected with an immature teeth with teeth diagnosed as either vital (asymptomatic irreversible pulpitis or symptomatic irreversible pulpitis and the bleeding didn't stop after 5 minutes application of hemostatic agent) or non-vital pulp are indicated for regenerative endodontic procedure.

Patients will be divided randomly into three equal groups (n = 12):

Group 1(control group): Revascularization will be done using blood clot and RetroMTA as coronal barrier.

Group 2: Revascularization will be done using blood clot and DDM-TheraCal LC mixture paste as coronal barrier.

Group 3: Revascularization will be done using blood clot and TDM-Hydrogel as coronal barrier.

CBCT image will be obtained for baseline records before treatment and after placement of the final resin restoration, then the patients will be recalled after 3, 6, 9 and 12 months for evaluating any changes in dentin bridge formation, root length, root canal width, apex diameter and lesion size if present.

Inclusion Criteria:

• Systemically healthy patients (i.e., free of any systemic diseases).
• Patients presenting with immature permanent single-rooted teeth.
• Age: 9 -15 years.
• Teeth diagnosed as either vital (asymptomatic irreversible pulpitis or symptomatic irreversible pulpitis and the bleeding didn't stop after 5 minutes application of hemostatic agent) or non-vital pulp.

Exclusion Criteria:

• Patients who are allergic to any drugs used in this study or with systemic illness
• Teeth that are grossly decayed or fractured and require post and core as final restorations
• Presence of periodontal pockets greater than 4 mm.
• Radiographical evidence of apical foramen less than 1 mm.
• Presence of periapical radiolucency exceeding 10 mm.
• Presence of external or internal root resorption.
• Patients with a history of major surgeries like cardiac, kidney transplantation, haemodialysis.