Purpose: Because the maxilla and its alveolar process are prone to resorption after tooth loss, it is often necessary to perform a bone augmentation procedure to successfully carry out implant treatment in that region. The aim of this study was to determine the adhesive force between the sinus membrane and the osseous sinus floor that occurs during sinus floor elevation with a balloon lift system. Materials and Methods: Twenty-two ex vivo pig heads were used for this study. Access to the maxillary sinus was gained via the lateral sinus wall. Sinus elevation was performed using an inflatable balloon, which was consecutively filled with 3 mL of a radiopaque fluid. Pressure was monitored directly and continuously during the elevation procedure with an electronic pressure gauge. The integrity of the membrane was checked microscopically and macroscopically. Results: The average adhesion force of the sinus membrane was found to be 748 ± 65.56 mmHg. On microscopic and macroscopic inspection, no mucosal tearing occurred during sinus floor elevation. Underwood septa, when present, did not significantly influence the adhesion forces. Conclusions: The balloon system allowed for reproducible real-time measurement of the elevation forces and soft tissue resilience of the sinus membrane during the elevation process in this animal model. No mucosal ruptures were caused with this technical setup, in which effective elevation pressure ranging from 660 to 880 mmHg was not exceeded. A possible transfer of this technical setup to clinical procedures in humans requires investigation. Keywords: balloon lift, elevation forces, resilience, sinus floor elevation, sinus membrane