Computer Guided Low Window Sinus Lift Technique
Condition: Sinus Perforation
Study type: Interventional

Summary: 
      The study group included 12 patients that were treated using the low window lateral sinus
      lift technique with simultaneous implant placement. This was facilitated using a CAD-CAM
      generated surgical guide. Subjective assessment on postoperative pain and swelling as well as
      objective assessment of implant stability, vertical bone height gained and complications such
      as Schneiderian membrane perforation rates and bleeding.
    

Detailed description: 
      Presurgical assessment of each patient was performed. Preoperative impressions were taken and
      study models were mounted. Orthopantogram (OPG) and cone beam computer tomography (CBCT) of
      the targeted areas were also done in order to evaluate residual bone height between the
      alveolar bone crest and the sinus floor, residual ridge width, bone quality and planning the
      number, size and position the implants.

      Designing the surgical guide was performed using In2Guide™ system powered by OnDemand3D™.

      The low window design was also planned where the lower osteotomy line will be flushed with
      the floor of the sinus, the upper line is 6mm of height from the lower line, the mesial line
      is flushed with the anterior wall and the distal line will correspond to the position of the
      most distal implant. The final product was fabricated using OnDemand3D™ which was then
      transferred to the 3d printer machine.

      Patients were instructed to rinse with 0.125% chlorhexidine antiseptic mouth-wash for 2
      minutes prior to surgery. The surgical area was anesthetized with local anesthesia.
      Infraorbital and greater palatine nerve blocks and local infiltration were given in order to
      properly anesthetize the area. A crestal incision was made in the posterior edentulous area
      followed by a vertical incision made at 45 degrees distal to the most anterior tooth. A full
      thickness mucoperiosteal flap was elevated at the surgical site enabling the apical osteotomy
      line to be drawn at a distance of 6mm above the residual bone height from the ridge. The
      customized surgical guide was secured in its proper position. After drilling, the anchor pin
      was placed in the prepared place. Using the standardized piezoelectric tip (SL1) with sterile
      saline irrigation, the outline of the window in the lateral maxillary sinus wall was formed.

      The bone window was thinned down using the specialized DASK drill #4 and #5 from the DASK Kit
      until the grey shadow of the sinus membrane becomes visible. The sinus membrane at the
      circumference of the bony window was detached using the dome-shaped Sinus Membrane Elevator
      (XSE1L). Sinus membrane elevators (XSE2L), (XSE3L) and (XSE4L) were used to carefully lift
      the sinus membrane from the floor and anterior wall of the sinus to create adequate space for
      graft material (Figure 2-b). The membrane was further elevated to the medial wall in order to
      provide additional blood supply from that bone. The implants were drilled in the positions
      indicated by the surgical guide. Half the amount of the xenograft was introduced into the
      cavity followed by insertion of the dental implants. The dental implants were placed at
      torque 30~45N‧cm. Stability of the implants was measured using an implant stability meter.

      Filling the cavity with the rest of the xenograft was completed after implant placement(s).
      The size of the collagen membrane was adjusted to match the size of the lateral bone window
      and then placed and stabilized by the cover screw. The flap was released by short horizontal
      cuts in the inner surface of the mucosa to provide a tension free flap. This was followed by
      closure of the flap with water tight sutures (horizontal mattress with a single interrupted
      it's centre) using 3/0 silk suture material.

      After 6 months from the operation, a small incision was made directly over the implant and
      the cover screw was removed. Implant stability was measured again using the Osstell device.
      The abutment was placed at torque 25~30 N.cm. An impression was taken and sent to the lab for
      fixed prosthetics construction. The fixed prosthesis was cemented using glass ionomer cement.
    

Intervention name(s): Low Window Sinus Lift technique
Intervention type(s): Procedure
Intervention description(s): Preoperative CBCT of surgical site and Fabrication CAD/CAM surgical stent, Sinus elevation using "Low Window Sinus Lift" technique, Implant, bone graft and membrane placement
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: sinus augmentation