Placing implants in the posterior maxillary area has the drawback of working with scarce, poor quality bone in a significant percentage of cases. Numerous advanced surgical techniques have been developed to overcome the difficulties associated with these limitations. Subsequent to reports on the elevation of the maxillary sinus through the lateral approach, there were reports on the use of the crestal approach, which is less aggressive but requires a minimal amount of bone. Furthermore, it is more sensitive to operator technique, as the integrity of the sinus membrane is checked indirectly. The main advantage of this new technique, Intralift, is that it does not require a minimum amount of crestal bone (indeed, the smaller the width of the crestal bone, the better this technique is performed). The possibility of damage to the sinus membrane is minimised by using ultrasound based hydrodynamic pressure to lift it, while applying a very non-aggressive crestal approach. Conclusions: We believe that this technique is an advance in the search for less traumatic and aggressive techniques, which is the hallmark of current surgery.

An essential condition for success in dental implant treatment is the amount and quality of bone in the area on which we decide to place the implant after careful diagnosis and planning. The posterior area of the upper jaw has anatomical features that make it unique compared to other areas, mainly due to the presence of the maxillary sinus. After tooth loss there is progressive bone resorption, combined with sinus pneumatization and loss of bone height and quality, which greatly hinders the placement of dental implant.

Sinus lifting procedures are performed routinely to provide the required height of proper and stable bone tissue around the dental implants to be inserted. The surgical technique of maxillary sinus Schneiderian membrane (MSSM) lifting with immediate/simultaneous installation of dental implants, generally results in significant bone formation. The recently reported graftless MSSM elevation procedure and the subsequent augmentation of bone have greatly changed our perspective of bone neoformation potential. The blood clot formed under the lifted MSSM appears to be of critical importance in bone neoformation potential, precluding the need for exogenous graft materials In elevation with the rotary technique, the main intraoperative complication is perforation of Schneider's membrane, which is observed in between 10-35% of all such operations, and which usually occurs in the osteotomy drilling phase while preparing the window for access to the sinus With the purpose of reducing the risk of perforating Schneider's membrane, vestibule osteotomy using ultrasound has been proposed, as this reduces the risk of soft tissue damage and percentage membrane perforation to 7%. Some studies in the literature are preliminary descriptions of the technique, while others present isolated cases and others in turn report case series - no significant differences being observed between the two techniques The selective cutting is the result of the limited amplitude. At this amplitude, only mineralized tissue will be cut, because soft tissue requires frequencies of greater than 50 kHz. Therefore, the use of piezoelectric instruments will reduce the risk of nerve damage. The reduction of overheating is explained by the generation of a cavitation effect in the irrigation solution due to the mechanical micro-movements at a frequency of approximately 25-30 kHz. This also accounts for reduced bleeding, which means better surgical visibility and increased safety.

Perforation of the Schneiderian membrane doubles the risk for the incidence of sinusitis or infection. Therefore, it is of great importance that any perforation should be avoided. The use of the piezoelectric device reduces the frequency of membrane perforation among surgeons with limited experience. Specific tips can even decrease the risk of accidental or iatrogenic perforations.

Inclusion Criteria:

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The following inclusion criteria will be established: (Llopet et al., 2014) Inclusion criteria: edentulous maxilla in premolar-molar areas with a residual ridge height of 9 mm or less.

Exclusion Criteria:

• Exclusion criteria: sinuses with septa in the operated area, polyps, sequelae of fistulas or fractures.

Cases for current study will be selected free from local pathosis. Patients will be free from any systemic disease that could affect their reparative power.

patients are eligible for implant placement older than 18 years old

I will check with my study chair

double ( participant- outcome assessor) single blinded