After the endodontic procedure, MTA will be placed into the apical 4 mm of the root canals. then a moist cotton pellet will be placed and the access cavity will be restored with GIC. Next day, GIC and the cotton pellet will be removed the coronal and middle third of the root canal will be filled with gutta-percha. The coronal restoration will be completed with GIC, composite.

After the endodontic procedure, Premixed Bioceramic Putty (Well-Root™ PT) will be placed into the apical 4mm of the canals. After 12 min, the coronal and middle third of the root canal will be filled with gutta-percha. The coronal restoration will be completed with GIC, composite.

Apexification treatment was done with mineral trioxide aggregate

The apexification procedure will be recorded as a clinical success if the tooth fulfils the following criteria: (1) No pain, (2) No swelling, (3) No tenderness to percussion, (4) No abscess or fistula, and (5) No abnormal tooth mobility.

The apexification procedure will be recorded to be radiographically successful if it demonstrates the following criteria: (1) reduction of apical lesion size (2) Normal periodontal ligament space (2) No furcation pathosis, and (3) No external resorption.

The apexification procedure will be radiographically unsuccessful if the apical lesion size increases.

The apexification procedure will be doubtful if the apical lesion size doesn't change

Radio-graphically, the periapical index provides an ordinal scale of 5 scores ranging from ''healthy'' to ''severe periodontitis with exacerbating features''. (1) Normal periapical structures. (2) Small changes in bone structure. (3) Changes in bone structure with some diffuse mineral loss. (4) Periodontitis with well-defined radiolucent area. (5) Severe periodontitis with exacerbating features. (1, 2: healthy and 3, 4, 5: pathological).