Storage and mixing systems for pasty two-component polymethyl methacrylate bone cements comprise a tubular cartridge having a cylindrical inner chamber, a cartridge head, which closes one end of the tubular cartridge at the front side, a partition that is disposed axially in the cylindrical inner chamber of the cartridge. The partition divides the cylindrical inner chamber of the cartridge bounded by the cartridge head into two cavities that are spatially separated from one another, wherein a first pasty cement component is present in the first cavity and a second pasty cement component is present in the separate second cavity. The systems further comprising two dispensing plungers axially displaceable in the two cavities of the cartridge, wherein the dispensing plungers close the two cavities on the back side of the cavities situated opposite the cartridge head, a bending device for deforming the partition, wherein the bending device is axially movable in the cartridge and is disposed, or is to be disposed, behind the dispensing plungers, as seen from the cartridge head, wherein the bending device has a deflection surface that is inclined with respect to the axis of the cartridge and pushes the partition laterally in the direction of the inside wall of the cartridge when the bending device is pushed into the cartridge.