MICROSCOPE-CONTROLLED INTERNAL SINUS FLOOR ELEVATION (MCI-SFE): A NEW TECHNIQUE TO EVALUATE THE SINUS MEMBRANE DURING TRANSCRESTAL LIFTING

Abstract

Transcrestal (or “internal”) sinus floor elevation (SFE) can be performed when the residual alveolar ridge has adequate vertical (≥6 mm; SA 1 and SA 3 as classified by Misch) and horizontal dimensions. Although this surgical technique is currently established, it has two shortcomings. First, internal SFE is considered a “blind” approach as far as verification of the elevated osteomucosal layer on the sinus floor is concerned. Also, no guidelines supported by scientific evidence are currently available as to the vertical dimension that can be attained by elevation and grafting without injuring this osteomucosal layer. The present investigation explains a new visual controlling method during evaluation of the osteomucosal layer on the sinus floor, which is based on the use of high-powered optical magnification and accordingly has been termed “microscope-controlled internal” SFE (MCI-SFE), and also examines the influence of elevation heights on the frequency of perforation and other complications during and after SFE. Fifty-nine internal SFE procedures were verified with this technique in 43 patients, who were divided into three study groups depending on the planned height of elevation and they received a total of 60 implants. The clinical and radiographic results of this study demonstrated that the risk of injury to the osteomucosal layer and the associated risk of incurring additional complications such as implant loss and sinusitis would increase significantly in the presence of elevation and grafting heights of ≥4 mm. Whenever possible, therefore, elevation of the sinus floor in internal SFE procedures should be less than 4 mm. Using an operating microscope for visual inspection of the osteomucosal layer of the sinus floor improves surgical success and contributes to better outcomes of internal SFE.