Instrument separating the maxillary sinus membrane, applicable for use in sinus elevation procedures using crestal technique, in which the entire process of sinus membrane elevation and bone graft placement is carried out through the bony perforation in the alveolar crest made for the subsequent placement of the dental implant, and that, formed from an elongated metal body comprising a central handle (2) of cylindrical configuration, at the respective ends of which there are respective active platforms (4), disc-shaped, convexly flattened and with the working surface (4a) slightly inclined toward the center of the instrument, which are joined to the handle (2) by respective connectors (5) located after the rectilinear extensions (6) provided at both ends of the body of the handle (2), it is characterized in that the active platforms (4), which are of different diameter (d), have a to them of a diameter of discal plantar of 3 millimeters and the other of 4 millimeters； because the connectors (5), which are determined by respective rod segments, have an angle (a) with respect to the handle (2) of between 90º to 120º and because said connectors (5) are provided with calibration marks (7) to know precisely the working depth of the corresponding active platform (4). (Machine-translation by Google Translate, not legally binding)1. Instrumento separador de la membrana del seno maxilar que, aplicable para su utilización en intervenciones de elevación sinusal mediante técnica crestal, en que todo el proceso de elevación de la membrana sinusal y la colocación del injerto de hueso se lleva a cabo a través de la perforación ósea en la cresta alveolar realizada para la posterior colocación del implante dentario, y que, conformado a partir de un cuerpo alargado de metal que comprende un mango (2) central de configuración cilíndrica, en cuyos respectivos extremos existen respectivas plataformas activas (4), en forma discal, aplanada convexa y con la superficie de trabajo (4a) lige
