# Crystal Sinus Lift with the Hydrodynamic Technique: Prospective Clinical Study at 3 Years Follow-Up
## 2 Materials and Methods
### Surgical procedure
#### Surgical protocol  
The patient was prepared for surgery with an oral rinse using a chlorhexidine digluconate mouthwash at 0.12% for one minute. Under local anesthesia with articaine and adrenaline 1:100,000 (Septanest, Saint-Maur-des-Fosses Cedex, France), a crestal marginal incision was made with a full-thickness flap to expose the alveolar crest. The implant site was created using a sequential set of drills with appropriate cutting angles to gently erode the cortical floor of the sinus ([PERSON]'s technique). This set of drills comprised 11 pieces of the same diameter (3.1 mm) but of variable and increasing lengths, ranging from 2 to 12 mm. These drills allowed the Schneiderian membrane to be reached without tearing it, enabling subsequent graft insertion and sinus lift. The implant location was marked using a small-diameter pilot drill, 1 mm in length, working through the cortical bone and using a prefabricated surgical guide. After intermediate, larger-diameter drilling, the implant site was prepared 1 mm below the sinus floor using a lifting drill, 1 mm shorter than the height of the alveolar crest, as indicated by  
Figure 1: CBCT cross-section. the periapical radiograph. A parallel pin was then inserted into the surgical site to check the exact height of the alveolar ridge below the sinus floor using an intraoperative X-ray. A final lifting drill, 1 mm longer than the crest height, was used until the shoulder stop reached the ridge. The alveolar bone was then checked with a special rounded probe to confirm complete bone erosion prior to lifting the sinus membrane. After verifying the integrity of the sinus membrane using an appropriate probe and the Valsalva maneuver, a porcine xenogenic bone substitute in the form of a pre-heated (40 \({}^{\circ}\)C) gel (Gel 40, Tecnoss, Giaveno, Italy) was injected through the crestal antrostomy to elevate the membrane and fill the sub-antral space (Figure 2A-D). At this point, an intraoperative intraoral X-ray was performed to confirm the elevation of [PERSON]'s membrane and measure the new distance from the alveolar crest (Figure 3). The new bone height, achieved through the sinus lift, allowed for the placement of an implant with an insertion torque higher than 25 Ncm, ensuring primary stability. An intraoperative periapical X-ray was then performed, confirming the correct positioning of the implant and the mechanical engagement between the apex of the fixture and the grafted material. This engagement was considered a crucial factor as it provides additional stability to the implant (Figure 4). Figure 3: The obtained distance between [PERSON]’s membrane and the alveolar crest. Figure 2: (**A**) A syringe of xenogenous porcine bone substitute in gel form with a stainless steel insert to facilitate graft injection. (**B**) After performing crestal osteotomy and checking the [PERSON] membrane’s integrity, (**C,D**) the graft is directly injected into the sub-antral space. _Post-surgical protocol_  
At the end of the surgery, a control CBCT was performed, which confirmed the adequate prosthetic emergence of the inserted implant and the success of the surgical procedures. Additionally, it clearly showed that the graft material in gel form, by detaching the membrane at points of least resistance, enabled a mini sinus lift even at the apex of the implant fixture (Figure 5). Antibiotic therapy was continued for the next 5 days (1 g every 12 h--amoxicillin in combination with clavulanic acid or clarithromycin in case of allergy). In addition, analgesic therapy (non-steroidal anti-inflammatory drugs, as needed) was prescribed for each patient. Mouth rinsing with a chlororexidine-digluconate-containing solution (0.2%) was recommended twice daily for 10 days [26]. One week after the surgical procedure, the sutures were removed. _Prosthetic rehabilitation_  
Four months post-surgery, the implant site was reopened. The closure screw was removed and replaced with a healing abutment to facilitate soft tissue healing around the implant. After 10 days, the sutures were removed.