Maxillary Sinus Floor Elevation Following Simultaneous Implant Installation Without Graft Material
Condition: Insufficient Bone Volume in Posterior Maxilla
Study type: Observational

Summary: 
      The present study describes and evaluates the surgical protocol for sinus mucosal lining
      elevation of the maxillary sinus for Dental Implant Insertion without Bone grafting
      Underneath the Sinus Membrane.
    

Detailed description: 
      Restoration of lost dentition in the severely atrophic posterior maxilla has for the last 2
      decades been successfully treated with various sinus augmentation techniques and installation
      of dental implants. The use of graft material is anticipated to be necessary; however, recent
      studies have demonstrated that the mere lifting of the sinus mucosal lining and simultaneous
      placement of implants result in bone formation. This study was conducted in order to evaluate
      simultaneous sinus mucosal lining elevation and installation of dental implants without any
      graft material.

      The present study describes and evaluates a modification of the surgical protocol for sinus
      mucosal lining elevation and simultaneous installation of osseointegrated implants with a MIS
      implant system (Seven ™) ,in 20 patients.

      Preoperative Examination: (Screening):

        1. Medical History

        2. Clinical Examination

             1. Oral hygiene.

             2. Oral mucosa condition.

             3. Number of missing teeth in the posterior maxilla.

        3. Radiographic Examination (CT and Panoramic X-ray)

             1. Sinus Maxillary condition.

             2. Sub-antral bone height.

             3. Bone jaw condition. Selected patients under the "inclusion criteria" will be
                included in the study after they will have explanation and signed on informed
                consent.

      Surgery:

      All patients will be operated on under local anesthesia (2% Xylocaine Dental with epinephrine
      1:100,000;) or General anesthesia ( the type of the anesthesia will be decided by the
      patients) at Carmel medical center Haifa.. Preoperative antibiotics will orally administered
      45 minutes before surgery; patients routinely received 2 g of Augmentin or 600 mg of
      clindamycin (when allergic to penicillin).and 6mg of Dexamethasone 1 hour before surgery.

      Surgical Technique:

      The posterior maxillary edentulous area and the maxillary sinus wall will be exposed via a
      crestal incision and a buccal muco-periosteal flap will be raised. Osteotomy in a oval or
      rectangular fashion will be made with round Drill 5 mm radius in the anterior wall of the
      sinus, 5 to 6 mm cranial to the intended implant site (Fig 1). With small sharp elevators the
      cortical bony window will be pulled in the sinus cavity.

      Perforations of various sizes of the sinus mucosal lining will be treated by drilling small
      holes in the bone above the cortical window to elevate and suture the mucosal lining to that
      level using absorbable sutures (Vicryl 6-0). If there is success in this technique we will
      use a small piece of periosteum (taken from the buccal flap) which will be placed as a lid
      over a perforation of the sinus mucosal lining. If the perforations are so small (less than 1
      mm) then further dissection of the mucosal lining and "tenting" by the implants will be
      considered satisfactory for a blood clot to form around the implants.

      After the elevation, implants will be installed in the residual sub-antral bone. The
      remaining bone height will be recorded with a depth gauge during surgery. Primary implant
      stability will be noted manually at installation. A stabilizing wrench will be used when
      removing the implant carrier in all cases.

      To achieve implant stability in the cases of small remaining levels of vertical subantral
      bone, the protocol of installing the MIS system dental implant was modified in its last
      preparation step. The final conical burr was leveled into the bone 1 to 2 mm less than the
      recommended standard protocol in cases with only 2 to 3 mm residual bone. Thus, a slightly
      smaller hole for the implant was prepared and the implant could be placed with better primary
      stability, utilizing the effect of the conical design and the retention of the microthreads
      in the superior part, adding an extra effect to the placement and thereby achieving
      sufficient primary stability. The compartment around the implants under the sinus mucosal
      lining in the sinus floor will be filled with blood from surrounding bleeding (Fig 2), and
      dental membrane (Zimmer Ltd.) will be placed on the open window, then the incision will be
      closed with resorbable sutures (Vicryl 3/0. Ethicon Inc

      Postoperative Care:

      Analgesics will be prescribed with Optalgin or with a nonsteroidal anti-inflammatory drug for
      1 to 2 weeks following the surgery. Antibiotic treatment will be continue for 10 days
      postoperatively with Augmentin 875mg Twice a day (or clindamycin, 300 mg 3 times daily for
      penicillin allergic patients). Patients should be instructed not to blow their nose and to
      use nasal spray saline for 14 days after surgery. Wearing dentures will not be allowed for 10
      days following the surgery.

      Patients will be reviewed and sutures taken out after 7 to 10 days. Clinical and Radiological
      Follow-up The patient will be recalled to the out patient clinic in Carmel Medical Center,
      for a follow up. All patients will be checked in the surgery site and x-ray radiograph will
      be made.

      Radiological follow up:

      Periapical radiographs and Panoramic X-ray will be used for measurements of 1) the height of
      the residual alveolar bone at each implant site, and 2) the height of newly formed bone in
      the maxillary sinus in relation to each implant. Measurements will be made manually with a
      millimeter scale. The cervical micro-threaded area of the implant will be used as a reference
      point during measurement.

      Criteria for considering the procedure as successful:

        1. Successful implants ( no pain, no infection, stable implants) at the uncovering
           procedure.

        2. Periapical and panoramic x-ray at the endpoint shows a bone formation around the implant
           inside the maxillary sinus.

      Uncovering of the implant will be done 6 month after the surgery. All patients will be
      operated on under local anesthesia (2% Xylocaine Dental with epinephrine 1:100,000;) the
      implant instillation area and the maxillary sinus wall will be exposed via a crestal incision
      and a buccal mucoperiosteal flap will be raised.

        1. A healing cap will be inserted in the implant.

        2. A punch of 2mm biopsy will be take from the maxillary wall. The incision will be closed
           with resorbable sutures (Vicryl 3/0. Ethicon Inc) around the healing cap.

      The referring dentists will carried out the prosthetic rehabilitation after two weeks for the
      uncovering procedure. All patients will be recalled for follow up after the prosthetic
      rehabilitation 2 and 4 months in our out patients clinic.

      Statistics Descriptive statistics will be used and the correlation of results will be
      confirmed with linear regression analysis.
    

Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Patients (women, men) with a range of a age 18-65 years will be consecutively included. The
        patients will be referred to the Department of Oral and Maxillofacial Surgery, Carmel
        Medical Center, Haifa, for dental implant treatment in the posterior maxilla from every
        Dental Clinic in Israel
      
Keywords: Maxillary Sinus; Bone Augmentation; Dental Implant; Sinus Membrane