Abstract: A capsule for the storage and vibration mixing of two components, particularly for dental uses comprises a mixing chamber in which one of the components is stored, the chamber having an aperture which is closed by means of a removable closure member and a foil bag which can be ruptured without disintegration by the mixing movement is housed in the mixing chamber and contains the other component in liquid form. The liquid component is a high specific gravity liquid such as mercury and the closure member is sealingly secured to that part of the capsule which forms the mixing chamber by a seal which has a predetermined breaking strength, formed conveniently by a weld or adhesive. Externally the closure member presents a cylindrical socket to which can be fitted a cylindrical lever for the purpose of breaking the seal to remove the closure member and allow access to the interior of the mixing chamber for withdrawal of the mix.