Table 1: The inclusion and exclusion criteria for Patients had been selected from a group of sixty patients recruited before in the same centre.

Inclusion Criteria Exclusion Criteria
Patients required a bilateral sinus lift for implant treatment in the posterior maxilla one side for crestal approach and other side for lateral approach. Patients who required a bilateral sinus, in which both the right and left sides were indicated for OSFE per current practice guidelines [6].
Patients were required to undergo a lateral sinus lift procedure if the RBS was a minimum of 2 mm and a maximum of 4 mm.
Patients need to meet the current practice guidelines (minimum of 5mm RBS) to qualify for crestal approach6
Patients required a bilateral sinus, in which both the right and left sides were indicated for sinus lift by the lateral approach per current practice guidelines [7, 8].
At least 1 mm of bone was required on each side for implant stability. Patients did not consent to participate in the study.
Patients were free from any systemic or local contraindications for dental implant placement. Patient with systemic or local contraindications for dental implant placement.