The current st udy's objective was to validate the repeated effect of i PRF with autogenous bone on the of gingival thickness , width a n d volumetric bone changes durig maxillary alveolar augmentation using cone beam computer tomography (CBCT). Patients and methods:

The study was a randomized clinical study in which participants needed to augment defective ridge were selected from the Outpatient Clinic, Department of Oral Medicine, Periodontology and Diagnosis , Faculty of Dental Medicine for Girls, Al Azhar University. The Research Ethics Committee, Faculty of Dental Medicine for Girls, Al Azhar University (REC code (P. PD 24 19 ) certified this study and a signed informed consent form with approval was obtained from each. Each patient who was enrolled in the study had a complete medical record and a proper clinical examination. These patients had to have a horizontal or vertical alveolar ridge deficiency and have enough bone in the mandibular donor site (external oblique ridge).

However, patients showing any signs of active periodontal disease, on long term corticosteroid therapy, persons taking bone metabolism drugs as well as individuals suffering from any systemic illness that may impact bone repair were excluded from the study.

Patients were assigned to one of two 2 groups, group I or group II. Group I, consisted of patients grafted with autogenous bone graft alone. I n Group II, patients were grafted using autogenous bone combined with repeated injection of i PRF Assessment of the alveolar ridge dimension and the bone block to be harvested preoperatively using CBCT. T he measurements of the alveolar ridge mesio distaly and bucco lingually in mm were determined at the recipient site . It was crucial to visualize the anatomic structures at the osteotomy site, including the alveolar canal, the mental foramina, and the teeth roots present to create ideal bone cutting planes according to the depth and extension of the graft without any injuries to the aforementioned structures.

Inclusion Criteria:

• patients who have a horizontal or vertical alveolar ridge deficiency

Exclusion Criteria:

• patients showing any signs of active periodontal disease
• patients on long term corticosteroid therapy,
• patients taking bone metabolism drugs
• patients suffering from any systemic illness that may impact bone repair