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Clinical Science and Techniques

Maxillary Sinus Augmentation Using Hydraulic Pressure by Lateral Approach and Simultaneous Implant Placement

Clinicoradiographic Study

Bhandari, Shilpy MDS*; Thomas, Raison MDS; Kumar, Tarun MDS; Shah, Rucha MDS; Mehta, Dhoom Singh MDS§

Author Information
doi: 10.1097/ID.0000000000000911
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The use of dental implants is an efficient and reliable option for patients affected by part or total edentulism. The success of implant therapy is governed by various host factors. One such major factor is the presence of an adequate quantity and quality of bone. The posterior edentulous maxilla, in comparison with other areas of the mouth, presents unique challenges to the implant surgeon. Lack of functional load onto the alveolar ridge after tooth extraction in the region results in a continuous remodeling process that leads to bone loss in both horizontal and vertical direction.1 Also, pneumatization of maxillary sinus because of the osteoclastic activity within the periosteum of the Schneiderian membrane further reduces the amount of bone available for placement of implants in posterior maxilla.2

The procedure of choice to restore this anatomical deficiency is maxillary sinus floor elevation (sinus lift).3 Sinus floor elevation is an internal augmentation of maxillary sinus, wherein maxillary sinus membrane (Schneiderian membrane) is elevated to place implants through the sinus floor.

The conventional sinus augmentation methods, including the lateral maxillary approach and crestal approach, have several shortcomings such as sinus membrane perforation, increased morbidity and postoperative pain, increased chairside time, and high cost of the procedure.

Chen and Cha4 in 2005 reported an ingenious technique to minimize these limitations and reduce the risk of Schneiderian membrane perforation by using sinus burs, condensers, and hydraulic pressure to elevate the sinus membrane through crestal approach and achieved 99.9% success rate. In 2012, this technique was further improvised by the introduction of water lift system by Kim and Itoh. In this technique, separation of Schneiderian membrane from lateral wall of the sinus was performed using the aqua system of the water lift kit.5 This hydraulic system exerts equal pressure on Schneiderian membrane for uniform elevation, eliminating “point sources” of pressure, which can hamper the membrane integrity.5

However, there are limited studies that have assessed the effectiveness of hydraulic pressure in the sinus lift procedure through lateral approach with immediate implant placement. Hence, the purpose of this study was to assess clinically and radiographically efficacy of maxillary sinus augmentation using hydraulic pressure in a lateral approach with immediate implant placement.

Materials and Methods

In this study, a total of 10 systemically healthy patients (8 men and 2 women) between the age groups of 30 to 60 years with good oral hygiene (plaque index scores of <1.9) and wishing for implant therapy were selected from the outpatient Department of Periodontology and Implantology. Smokers or subjects with medical history such as uncontrolled diabetes and hypertension or any sinus pathologies that could complicate the outcome of the study were excluded from the study. Intraoral periapical radiographs and cone beam computed tomography (CBCT) scans with surgical stents were taken before the study, and scans revealing residual bone height of 4 to 6 mm were selected for lateral approach sinus augmentation surgery.5 All the risks and benefits were explained to the study subjects, and written consent was obtained from them before the commencement of the study. Ethical approval for the study was acquired from the Institutional ethical committee (Ref No. BDC/Exam/434/2015-16).

Clinical parameters including plaque index, insertion torque, and implant stability were measured at baseline and 6 months postoperatively.6 Radiographically, CBCT analysis was used to assess the change in subantral bone height from baseline to the 6 months postoperatively.

Surgical procedure: A prophylactic dose of augmentin 625 mg (amoxicillin trihydrate 500 mg + potassium clavulanate 125 mg) was administered to the patient 1 hour before the commencement of the surgery. A preprocedural mouth rinse with 10 mL of 0.2% chlorhexidine was performed to reduce the bacterial load in the oral cavity before the surgery. Before the surgical procedure, the platelet-rich fibrin (PRF) preparation was performed. Ten milliliter of blood was withdrawn from the patient's antecubital vein and was subjected to immediate centrifugation at 2700 rotations per minute (RPM) for 12 minutes.7 PRF obtained was later used during the grafting procedure. Local anesthesia (2% xylocaine HCl with 1:80,000 adrenaline) was injected at the site of interest using posterior superior alveolar and greater palatine nerve blocks and infiltration as required. Crestal incision and vertical releasing incisions were given in the surgical site following which a full-thickness mucoperiosteal flap was reflected on the buccal side to expose the lateral wall of sinus (Fig. 1, A and B).

Fig. 1
Fig. 1:
(A) Clinical view of preoperative residual ridge; (B) Preoperative CBCT illustrating subantral bone height of 3.91 mm.

In this study, the lateral approach water lift system kit was used (Osung, Pearland, USA). A point-sized osteotomy site was prepared on the lateral maxillary sinus wall using an artificially intelligent (AI) drill at 1:1 6000 RPM using straight angle handpiece. The Schneiderian membrane was then separated from the lateral wall of the sinus using the aqua system. Once the aqua lifter along with syringe was snugly fitted into the provided slot, the trigger of aqua injector was pressed to inject 1 cc of saline through the prepared osteotomy site on the lateral wall. Depending on the case, saline was injected until the desired elevation of sinus membrane was achieved (Fig. 2).

Fig. 2
Fig. 2:
Mucoperiosteal flap reflected after crestal and vertical incision, exposing the lateral wall. A point-sized osteotomy prepared on lateral wall using AI drill. Saline is introduced into the osteotomy through the aqua system that exerts hydraulic pressure.

Furthermore, the window for the sinus lateral approach was prepared using the narrow or wide burin drill (Fig. 3). Sinus elevators were then used to detach the Schneiderian membrane from the underlying bone. The subantral compartment created was grafted partially with a 0.25 to 0.5 cc of calcium silicophosphate putty (NovaBone Dental Putty, Alachua, FL) and PRF clot (Fig. 4). Subsequently, implants of indicated lengths and diameters were selected and placed through crestal osteotomy (Fig. 5). Initial implant stability and insertion torque were measured using Osstell (Stampgatan Gothenburg) and a standard calibrated dental torque wrench, respectively. The subantral compartment was then completely filled with calcium phosphosilicate putty, and PRF membrane was placed over the window. Flap margins were approximated by horizontal mattress and interrupted sutures using 4-0 polyamide monofilament suture material. Routine postoperative instructions were given to the patients (Fig. 6). They were prescribed augmentin 625 mg twice daily for next 5 days and analgesic tablet Ketorol DT (Ketorolac) 10 mg twice daily for 5 days. Chlorhexidine rinses were prescribed twice daily for 2 weeks. The patients were instructed to limit themselves to a soft diet for the first 2 weeks after surgery. Patients were recalled after 2 weeks for suture removal. After that patients were placed on a monthly follow-up for 6 months. At the end of 6 months, all clinical parameters were recorded again, and a CBCT scan was taken (Fig. 7). Second-stage surgery was performed at the end of 6 months, and prosthesis was fabricated for patients (Fig. 8).

Fig. 3
Fig. 3:
Further lateral window preparation performed using burin drill and sinus membrane elevated from the sinus floor.
Fig. 4
Fig. 4:
After attainment of sufficient sinus lift, graft material is inserted through the lateral window after crestal osteotomy site preparation.
Fig. 5
Fig. 5:
Insertion of implants through the crestal osteotomy sites performed.
Fig. 6
Fig. 6:
Approximation of flaps with suture performed.
Fig. 7
Fig. 7:
CBCT view of subantral bone height 6 months postoperatively reveals increase in height up to 16.5 mm.
Fig. 8
Fig. 8:
Clinical view of implants after placement of healing caps.


A total of 11 implants were placed in 10 patients simultaneously with sinus augmentation. All cases showed clinically healthy mucosa without signs of infection during the follow-up period. The clinical radiographic data obtained were recorded at baseline and 6 months postoperatively, and the difference was assessed using Student's paired t-test.

The mean of plaque scores observed at baseline was 1.14 + 0.21, whereas the mean of plaque scores observed at 6 months postoperatively was 1.02 + 0.03 (P > 0.05). The mean values of the insertion torque were 34.54 + 3.5 Ncm. The mean implant stability at baseline was 65.45 ± 3.44 implant stability quotient, whereas 6 months postoperatively, it was found to be significantly higher at 72.09 ± 2.87 ISQ (P < 0.001). Radiographically, the total gain in the subantral bone height was calculated as the difference between the postoperative and preoperative subantral bone height. The mean of preoperative subantral bone height from the alveolar crest to the sinus floor was 3.86 ± 1.42 mm at baseline, whereas at 6 months postoperatively, it was 15.49 ± 2.73 mm (Fig. 7). The gain in the subantral bone height between preoperative and 6 months postoperative subantral bone height values was 11.63 ± 2.63 mm, which was found to be statistically significant (P < 0.001) (Table 1).

Table 1
Table 1:
Table Illustrating the Values of Clinical and Radiographical Parameters Measured at Baseline and 6 Months Postoperatively


The rate of success and predictability of implant treatment depends on several factors. Because of the low bone quality (D3-D4), the presence of maxillary sinus, and the tendency for progressive resorption after tooth loss, the posterior maxilla is a high-risk area for rehabilitation with implant-supported prosthesis.8 The procedure of choice to restore this anatomical deficiency is maxillary sinus floor elevation. Over the years, the lateral approach and crestal approach have been established as an accepted standard for treatment of the edentulous maxilla.

According to a study by Al-Dajani,9 it was concluded that lateral window approach in posterior maxilla can increase the residual vertical bone height to a distance of 9 mm and hence can be indicated in cases with minimal subantral bone height. According to systematic review by Corbella et al,3 the lateral approach sinus floor elevation technique is widely described in the literature and is recommended in cases of residual bone height lower than 4 to 5 mm. Hence, in our study, we chose cases with subantral bone height of 4 to 6 mm to be treated with lateral sinus lift. In the present case series, a total of 11 implants were simultaneously placed in 10 patients after sinus lift through lateral approach using hydraulic pressure. The lateral approach water lift system kit was used to achieve the same. Also, full mouth plaque scores were evaluated at baseline and 6 months postoperatively as oral hygiene maintenance impacts the success of implant therapy.10

Perforation of sinus membrane is one of the most common complications encountered during conventional lateral sinus floor elevation technique with an incidence rate of 7% to 56%.11,12 In a study by Nolan et al,13 upon evaluation of 359 augmented sinuses, the incidence of sinus membrane perforation was found to be 41%, which in turn had an impact on incidence of sinusitis and bone graft failure in the maxillary sinus. According to Schwarz et al,14 presence of sinus septa and residual bone height of less than 3.5 mm are the key risk factors for sinus membrane perforation. Also, it has been observed that implant survival with perforation of the membrane was 88.6%, whereas in those with intact membrane, the survival rate was found to be 98%.15 Moreover, in maxillary sinus lift procedures, the implant survival is negatively affected by membrane perforations and is found to inversely proportional to the size of the membrane perforation.16 Hence, in this study, use of hydraulic pressure technique was considered because it reduces the chances of membrane perforation. The specialized AI drill is sensitive to resistance, that is, can only drill when in contact with a solid substance such as bone and stops when comes in contact with soft tissue due to the drill control mechanism.5 This, in turn, is responsible for lower incidence of membrane perforation because it stops drilling the moment it comes in contact with Schneiderian membrane. The benefit of using hydraulic pressure is that in a closed system, it places equal pressure on all surfaces within the system. This equal pressure hence reduces the chances of membrane perforation by eliminating transmission of a point source of pressure, thereby gently elevating the Schneiderian membrane equally at all points of attachment thereby reducing likelihoods of membrane perforation, infection, and chronic sinusitis.9

The subantral compartment was grafted with alloplast and PRF clot. Utilization of alloplasts was considered as it is not associated with autograft-related drawbacks such as the creation of second surgical site, which result in pain and patient morbidity. Also, consistency of putty used is believed to deliver a cushioning effect onto the membrane by exerting a uniform hydrostatic pressure.17 L-PRF was used as it acts as a biologic barrier and provides a pool of growth factors such as transforming growth factor-b1 (TGFb-1), platelet-derived growth factor–AB, vascular endothelial growth factor, and matrix glycoproteins (such as thrombospondin-1) and accelerate the healing process at the elevated sinus floor.18

In the systematic review by Pjetursson et al,19 simultaneous sinus lifting and implant placement reported an implant survival rate of 90.1% after 3 years of follow-up. Hence, simultaneous implant placement was considered as it significantly reduces the treatment time and displayed similar survival rates as delayed implants. The mean insertion torque values were measured after the implant placement and were found to be between 30 and 45 Ncm during implant insertion for all the cases. These values are well within the optimum range and reflect good primary stability. A significant increase was observed when the implant stability immediately after insertion and 6 months postoperatively were compared. This finding is suggestive of improved bone implant contact at the end of 6 months. Our findings are in agreement with those by Kher et al.20

In this study, the gain in the bone height from baseline to 6 months postoperative was found to be significant with P value < 0.001, which is suggestive of substantial gain in the subantral bone height. This can be attributed to an atraumatic technique for posterior maxilla, use of hydraulic pressure, decreased chances of membrane perforation, good amount of gain in subantral bone height, simultaneous implant placement, and good compliance displayed by patients. No cases of membrane perforations were observed. Our results are in agreement with those presented by Kim and Itoh, Kim et al who used water lift system and reported a maximum elevation of sinus membrane to a height of 10.3 mm.5,21 These findings also demonstrate that lateral sinus floor elevation with hydraulic pressure is a technique that is predictable and results in an ample gain in the bone formation, less technique sensitive, and reduces chairside time.

However, small sample size, along with usage of specialized expensive kit for the procedure, and absence of histological analysis to assess the quality of bone formed are limitations of the study. Furthermore, more longitudinal and long-term multicenter studies are required to further substantiate their effectiveness.


Within the limitations of this study, the data obtained demonstrate that lateral approach sinus lift using hydraulic pressure with simultaneous implant placement shows promising results in the rehabilitation of atrophic maxilla.


The authors claim to have no financial interest, either directly or indirectly, in the products or information listed in the article.


Ethical approval for the study was acquired from the Institutional Ethical Committee (Ref No. BDC/Exam/434/2015-16), Bapuji Dental College and Hospital, Davangere, Karnataka, India.

Roles/Contributions by Authors

S. Bhandari: concepts, design, and literature research. R. Thomas: definition of intellectual content and literature research. T. Kumar: data acquisition and data analysis. R. Shah: manuscript preparation and manuscript editing. D. S. Mehta: manuscript editing and manuscript review.


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alloplast; CBCT; immediate implant placement; direct sinus lift; water lift system

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