An autoclave for the sterilization of clinical dental instruments is described, of the type comprising a sterilization chamber (1) equipped with a series of appliance fittings (4) for the inflow and outflow of fluids, and apt to contain a load of instruments onto which to carry through a sterilization cycle, characterized in that said appliance fittings (4) are gathered on at least one connection body or partition (3), with which a reducing container (7) is quickly able to be engaged and disengaged, which container has a volume apt to contain at least one instrument to be sterilized, the inner volume of such container (7) communicating with said appliance fittings (4) and said container (7) being apt to be entirely contained within said sterilization chamber (1). The small-volume container for said autoclave is further described, as well as a full treatment system employing said container.