The objective of this study will be to assess and compare between sub-periosteal self- inflating osmotic tissue expanders used as preparatory surgery before alveolar ridge augmentation and periosteal releasing incision using autogenous onlay block bone graft.

The assessment and comparison will be based on:

1. Change in edentulous alveolar ridge in bucco-lingual dimension after alveolar

   ridge augmentation.

2. Quantity of the soft tissue obtained after soft tissue expansion.

• Sixteen patients will be selected from the outpatient clinic of the department of, Oral medicine Periodontology, and oral diagnosis, Faculty of Dentistry, Ain Shams University.
• Three surgeries will be carried out for group I patient; the first is placement of soft tissue expander, the second surgery is bone grafting and placement of collagen membrane for ridge augmentation while the third (re-entry surgery) is implant placement in a routine fashion.

two surgeries will be carried out for group II patient; the first is surgery is bone grafting for ridge augmentation while the second (re-entry surgery) is implant placement in a routine fashion.

-Measurements and evaluation of edentulous ridge will be done by CBCT

Inclusion Criteria:

• All patients should have partially edentulous ridge (missing upper one or two neighboring anterior teeth or premolars) of the maxilla. The edentulous area should require horizontal bone augmentation procedures owing to lack of sufficient residual bone.
• All patients should not have any particular medical history (medically free) according to Burket health medical history questionnaire (Glick et al.2008).
• All patients should not have any known contraindication to oral surgery.

Exclusion Criteria:

• Smokers will be excluded from our study.
• Patients with poor oral hygiene or not willing to perform oral hygiene measures.
• Patients who showed residual infections in the edentulous area or apparent infection in a neighboring tooth.
• Patients with systemic diseases such as diabetes mellitus and hemorrhagic disorders, patients receiving intravenous bisphosphonate therapy or systemic corticosteroid treatment.
• Patients with occlusal discrepancies will be excluded.
• Vulnerable groups (as pregnant and lactating females, and decisionaly impaired individuals) will be excluded from the study.