For patients requiring LSFE, demographic data, including age, sex and smoking habits were collected. Preoperative CBCT images were analyzed for radiographic assessment of risk factors through measurement of sinus mucosa thickness, sinus lateral wall thickness, sinus width, presence of Underwood's septa, and presence of the alveolar antral artery. A bone consuming technique using piezosurgery was implemented. This technique involved eroding the buccal bone prior to window outlining followed mucosal elevation using novel ultrasonic curettes. sinus mucosa perforation, hemorrhage, and postoperative infectious complications were documented. The measurement of the studied factors was performed on Newtom VGI viewer software, by two evaluators J.B. and A.M.

Inclusion Criteria:

• Patients who received lateral sinus floor elevation using this new piezosurgery technique.

Exclusion Criteria:

• the usual exclsion criteria for external sinus lift procedure

All the patient needing lateral sinus lift procedure prior to implant placement.