A device for dispensing a dental material has a cartridge and a ball-shaped closure member. The cartridge and the closure member in combination form a rotary slide valve for selectively opening and closing a cartridge outlet for the dental material, such that the device can be operated between an operative position in which the cartridge outlet is open and a storage position in which the cartridge outlet is closed. The device further has a cannula which is removably receivable within the closure member. The cannula in the operative position of the device is mechanically locked against removal. The cannula further has an annular seal which in the operative position extends into the outlet.