This study is aiming to evaluate primary stability and bone gain in trans-crestal osseodencification technique using Regular concaved osteotomes at different height elevations.

For those patient who need up to 2-6 mm of vertical height, the 1-stage transcrestal osteotome technique shown to be stable over long term.

The most important negative factor that can be inferred from the results is that BAOSFE becomes less predictable when there is 4 mm or less of preexisting alveolar bone height beneath the sinus. Moreover, more challenging situation is the magnitude of tapping force, which may accidently perforate the antral membrane causing a lot of complication in the naso-antral apparatus by excessive taping force. The expansion of the osteotomy sites is performed with a number of Concave tipped tapered osteotomes with increasing diameters that are applied through the edentulous alveolar crest at the inferior border of the maxillary sinus floor. With each insertion of a larger osteotome, bone is compressed, pushed laterally and apically while pushing the garnered bone apically beneath the tented membrane.

Inclusion Criteria:

• Patients with edentulous vertically deficient posterior maxillary ridge a minimum 4 mm height of alveolar bone, and 6 mm in width.
• Both males as well as females without any active periodontal disease.
• All patients are in a good health with no systemic, immunologic or debilitating diseases that could affect normal bone healing.
• All selected patients are non-smokers and non-alcoholics.
• Patients are free from T.M.J troubles, abnormal oral habits such as bruxism.
• The edentulous ridges are covered with optimal thickness of mucoperiosteum with no signs of inflammation, ulceration or scar tissue.
• Remaining natural teeth have good periodontal tissue support and occlusion showed sufficient inter arch space for future prosthesis.

Exclusion Criteria:

1. On the local level, patients with maxillary sinus diseases, former sinus surgery and unfavorable inter maxillary relationship will be excluded.
2. General contraindications to implant surgery.
3. Subjected to irradiation in the head and neck area less than 1 year before implantation.
4. Untreated periodontitis.
5. Poor oral hygiene and motivation.
6. Uncontrolled diabetes.
7. Pregnant or nursing.
8. Substance abuse.
9. Psychiatric problems or unrealistic expectations.
10. Severe bruxism or clenching.
11. Immunosuppressed or immunocompromised.
12. Treated or under treatment with intravenous amino-bisphosphonates.
13. Lack of opposite occluding dentition/prosthesis in the area intended for implant placement.
14. Active infection or severe inflammation in the area intended for implant placement.
15. Need of bone augmentation procedures at implant placement.
16. Unable to open mouth sufficiently to accommodate the surgical tooling.
17. Patients participating in other studies, if the present protocol could not be properly followed.
18. Referred only for implant placement or unable to attend a 5-year follow-up.
19. Requiring only single implant-supported crowns.