A three-dimensional printing head including a dynamic mixer comprising a mixer casing, which delimits a mixing chamber, a supply inlet configured to supply the mixing chamber with a mineral composition and a discharge outlet; and an injector for injecting a building material admixture in the mixing chamber. The injector includes a tubular injecting member being flexible and having an injection outlet, the tubular injecting member being elastically deformable between a first state in which the tubular injecting member is configured to allow a flow of the building material admixture through the tubular injecting member and towards the injection outlet, and a second state in which the tubular injecting member is configured to prevent a flow of the mineral composition from the mixing chamber and through the tubular injecting member.