twenty recruited patients indicated for sinus augmentation and simultaneous implant placement will be divided into two groups (10 in each of the groups).to evaluate & compare bone formation & implant stability after shneiderian membrane elevation and augmentation with graft less tenting technique with different implant lengths.

group one will receive 8mm implant lenght while group two will receive 10mm implants.

Inclusion Criteria:

• patient with atrophic maxilla & pneumatized maxillary sinus with residual bone height at least 4mm of residual ridge
• both sexes

Exclusion Criteria:

• patients with systematic diseases that may affect normal healing
• sinus pathology
• heavy smokers more than 20 cigarettes per day