Study title: Comparison of clinical, radiographic, histological, and patient-reported outcome/ experience measures of endoscopically-monitored graftless transcrestal sinus floor (TSFE) elevation with 1-stage simultaneous multiple implant placement using osseodensification versus osteotomes in subsinus bone height of 4-5 mm: An 18-month double-arm randomized controlled trial.

Principal investigator: Georgina El-Ghoul, DDS, MSc. Contact: georginaelghoule@gmail.com Institution: Department of Periodontology, Faculty of Dental Medicine, Saint Joseph University of Beirut, Lebanon.

1. Introduction You are being asked to participate in a research study comparing 2 different procedures used in graftless TSFE with simultaneous implant placement in areas where there is limited amount of bone (4-5 mm) over a period of 18 months. TSFE is used to elevate the sinus membrane to allow new bone formation under the elevated membrane. TSFE can be achieved using either mechanical tools (osteotome) or specially designed burs (osseodensification burs). Currently, the 2 procedures are used by clinicians worldwide with excellent short- and long-term outcomes.

   You fit the selection criteria of patients enrolled in the study because you have partial posterior edentulism with more than one tooth missing and limited bone height below the maxillary sinus, a condition that is typically treated with graftless TSFE and simultaneous implant placement.

2. Purpose of the study The goal is to evaluate which technique, osseodensification or osteotomes, provides better bone healing, implant stability, and a more comfortable experience for the patient. TSFE procedures are blindly performed without direct intra-operative visualization of the sinus membrane. Since intra-operative sinus membrane perforation has been suggested to increase the risk of implant failure, the incorporation of endoscopy in TSFE provides a real-time magnified intra-operative view of the sinus membrane throughout the entire TSFE and implant placement, thus allowing a precise and controlled sinus elevation with minimal or no risks of perforation.

3. Procedures involved in this study

   If you agree to participate, you will be randomly assigned to one of 2 groups:

   • test group (osseodensification): sinus floor elevation using rotating burs; or
   • control group (osteotomes): sinus floor elevation using manual surgical instruments.

   The following will occur for all participants:

   • CBCT: pre-surgically, immediately at the end of the surgery, 6 and 12 months following delivery of the definitive prosthesis;
   • surgery: sinus floor elevation with simultaneous multiple implant placement using either osseodensification or osteotomes under local anesthesia;
   • endoscopic monitoring: TSFE is conventionally performed blindly without direct visualization of the delicate sinus membrane during the procedure. In this study, we will use a small specialized camera- an endoscope- through a very small bony hole located either within the surgical area or at a close separate location. This will allow us to enhance the procedure by visualizing the sinus interior and sinus membrane in real-time on a screen during the entire surgery. This monitoring technology will ensure that the sinus membrane stays intact while we create space for your implants, and therefore reduce the risk of implant failure;
   • biopsy (histomorphometric analysis): when possible, a small bone or implant-bone core that include osseointegrated non-strategic implants (prepared with the OD and OT approaches) along with a thin layer of surrounding bone will be retrieved and analyzed. The non-strategic implant is placed only for research purposes during the same appointment as your planned implants. It is not intended to support your planned bridge. The retrieval of this non-strategic implant involves a second minor and fast flapless procedure 6 months following the main surgery. This test implant will be sent to a laboratory to examine the bone-to-implant connection under a microscope. This will allow us to better understand how quickly and strongly the bone heals around implants using TSFE; and
   • follow-up (18 months): regular visits for evaluation and tooth cleaning at intervals of 3 months following delivery of the definitive prosthesis.

   You will be asked to complete surveys about your post-operative course and your overall treatment experience.

4. Risks involved Beyond the normal post-operative course which include potential discomfort, swelling, and hematoma, infrequent complications may occur such as post-surgical infection, bleeding, vertigo, and muscle spasms related to mouth opening. The CBCT radiation dose used each time is roughly equivalent to 6-9 months of natural background radiation (rocks, sun, air, flights).

5. Expected benefits to the patient Sinus augmentation will help generate bone around the implants that replace your missing teeth. Your participation will help improve future treatments for other