The aim of this study is to evaluate the clinical and radiographic outcomes of the indirect sinus lift procedure without bone graft material in edentulous patients requiring implant treatment in the posterior maxilla over a 2-year period.  All the participants will be explained the need and design of the study. Informed and written consent will be obtained from the patients. Thorough clinical case history will be recorded. A full mouth supragingival and subgingival scaling and root planing procedure will be performed. 2 weeks after phase I therapy, clinical evaluation and radiographic evaluation will be performed to confirm the suitability of the sites for this study. Clinical parameters like pain intensity from implant region, implant stability, modified plaque index (PI), modified sulcus bleeding index (mBI), probing pocket depth and width of masticatory mucosa (Wma) will be measured and radiographic parameters like RBH (residual bone height) at implant placement, peri-implant sinus bone levels, implant protrusion into the sinus and peri-implant crestal bone levels will be evaluated. Intraoral antisepsis will be performed with 0.2% chlorhexidine digluconate rinse and an iodine solution will be used to carry out extra oral antisepsis. After administration of local anaesthesia, horizontal crestal incision following, mucoperiosteal flaps will be reflected. To perform indirect sinus lift using CAS kit, first twist drill with appropriate size stopper will be used to reach 2mm short of the sinus floor. After this, CAS drills will be used sequentially till the implant size is reached using the same stopper. The goal will be to widen the osteotomy till the desired implant size. After performing the osteotomy, we will start going deeper by changing the stopper sequentially in 1mm increments till the drop into the sinus floor is felt. Depth gauge will be used to check if the sinus floor has been reached. The membrane will now be lifted using the hydraulic lift system provided. Saline will be used to aid in the lifting procedure. A suitable size OSSTEM implant body will be placed with the help of a rachet. The implant body will be covered by cover screw. The mucoperiosteal flaps will be repositioned and secured in place using non-absorbable black silk surgical suture. The interrupted suture will be placed. At Stage 2 – cover screw will be removed and healing abutment will be placed (4 months after stage 1 surgery). 1 month after stage 2 surgery impression will be taken for crown prosthesis and crown will be delivered soon after it is prepared. All implants placement will be done by single trained surgeon at stage 1 and stage 2 surgery. In postoperative care antibiotics like amoxcillin 500mg tid for 5 days and analgesic diclofenac sodium 50mg + paracetamol 500mg tid for 5 days will be prescribed, along with chlorhexidine digluconate rinse twice daily for 2 weeks. Sutures will be removed after 10 days postoperatively. Each patient will be reinstructed for proper oral hygiene measures at each appointment, and re-examined at 6 months, 1 year and 2 year. Soft and hard tissue evaluation will be performed at at stage 1 surgery, stage 2 surgery, 6 months,1 year and 2 year follow up. For hard tissue re-evaluation, CBCT of the same study site will be carried out.