TRACK-system distractors for vertical alveolar distraction have been tested biomechanically under different in-vitro-conditions. Additional torque measurements on patients during the clinical course of distraction were conducted to differentiate clinical and in-vitro data. Experimental findings and clinical trials led to the conclusion that according to indication and appropriate size of the device biomechanical stability and proper function can be assured under normal circumstances. Keywords: vertical distraction stability, biomechanical investigation