A mixing capsule (22, 23, 24, 25) for producing a dental preparation, wherein the mixing capsule (22, 23, 24, 25) has: a capsule body with a mixing chamber for receiving a mixing component and for mixing the dental preparation from the mixing component, a first fluid and a second fluid, and with an exit opening for discharging the dental preparation, a first cavity for receiving the first fluid, a first piston body (2, 2'), which delimits the mixing chamber in the capsule body and which has a first duct for guiding the first fluid from the first cavity into the mixing chamber, a second cavity for receiving the second fluid, and a second piston body (2, 2'), which delimits the mixing chamber in the capsule body and which has a second duct for guiding the second fluid from the second cavity into the mixing chamber, characterised in that A) the mixing capsule has a sleeve which at least partially encloses the capsule body and which is to be arranged relative to the capsule body in at least a first and a second position, the sleeve in the first position closing the exit opening and the exit opening in the second position being exposed so that the dental preparation can be discharged through the exit opening, and/or B) the mixing capsule (22, 23, 24, 25) has a sleeve which at least partially encloses the capsule body and which is to be arranged relative to the capsule body in at least a third and a fourth position, the sleeve having a cavity for receiving an admixing component, the sleeve in the third position being arranged such that the cavity is connected to the mixing chamber, so that admixing component can reach the mixing chamber, and the sleeve in the fourth position being arranged such that the cavity is closed off from the mixing chamber and from surroundings of the mixing capsule (22, 23, 24, 25). a capsule body with a mixing chamber for receiving a mixing component and for mixing the dental preparation from the mixing component, a first fluid and a second fluid, and with an exit opening for discharging the dental preparation, a first cavity for receiving the first fluid, a first piston body (2, 2'), which delimits the mixing chamber in the capsule body and which has a first duct for guiding the first fluid from the first cavity into the mixing chamber, a second cavity for receiving the second fluid, and a second piston body (2, 2'), which delimits the mixing chamber in the capsule body and which has a second duct for guiding the second fluid from the second cavity into the mixing chamber, characterised in that A) the mixing capsule has a sleeve which at least partially encloses the capsule body and which is to be arranged relative to the capsule body in at least a first and a second position, the sleeve in the first position closing the exit opening and the exit opening in the second position being exposed so that the dental preparation can be discharged through the exit opening, and/or B) the mixing capsule (22, 23, 24, 25) has a sleeve which at least partially encloses the capsule body and which is to be arranged relative to the capsule body in at least a third and a fourth position, the sleeve having a cavity for receiving an admixing component, the sleeve in the third position being arranged such that the cavity is connected to the mixing chamber, so that admixing component can reach the mixing chamber, and the sleeve in the fourth position being arranged such that the cavity is closed off from the mixing chamber and from surroundings of the mixing capsule (22, 23, 24, 25). A) the mixing capsule has a sleeve which at least partially encloses the capsule body and which is to be arranged relative to the capsule body in at least a first and a second position, the sleeve in the first position closing the exit opening and the exit opening in the second position being exposed so that the dental preparation can be discharged through the exit opening, and/or B) the mixing capsule (22, 23, 24, 25) has a sleeve which at least partially encloses the capsule body and which is to be arranged relative to the capsule body in at least a third and a fourth position, the sleeve having a cavity for receiving an admixing component, the sleeve in the third position being arranged such that the cavity is connected to the mixing chamber, so that admixing component can reach the mixing chamber, and the sleeve in the fourth position being arranged such that the cavity is closed off from the mixing chamber and from surroundings of the mixing capsule (22, 23, 24, 25).