A device for settling and filtering particles from dental surgery waste waters that comes out of dental surgery units, comprising a separation and filtering device with a cyclone-current generating geometry and a dual pore-size filter, wherein the device comprises: (a) a device main-body arranged at the upper side of the device; (b) a container arranged at the lower side of the device; (c) a filter housing; (d) a dual pore-size filter arranged in the filter housing comprising a first (5,6,44,57) and a second (5,6,43,56) axially stacked cylindrical filter elements having different pore sizes, the first filter element being located underneath the second filter element; (e) a central outlet orifice (17,47) in the main-body through which the treated waste water exits the device with the assistance of a vacuum power from a remote vacuum generator; (f) two symmetrical inlets in the main body for evacuating dental surgery waste water comprising air fluid and solid particles, from the mouth of the patient with the assistance of the vacuum power; (g) a cyclone generator formed between the container and the external surface of the filter housing upstream of the filter housing that spins said air fluid and solid particles against the walls of said container; and (h) a spring valve (49,50) and air insert for each inlet to control the flow from the mouth of the patient into the device; wherein the device is arranged so that after flowing through the cyclone generator. i) a flow is formed going radially inwards into the first filter element having larger pores than the second filter element, then into the inner space of the second filter element having smaller pores and outwards through the second filter element toward the central outlet: or ii) two flows are formed, the first flow going radially inwards into the first filter element having smaller pores than the second filter element and then through the inner space of the second filter element towards the central outlet and the second flow going through a deflection wing between the filter elements which causes the particles to separate by particle size and then going radially inwards through the second filter element having larger pores and toward the central outlet. (a) a device main-body arranged at the upper side of the device; (b) a container arranged at the lower side of the device; (c) a filter housing; (d) a dual pore-size filter arranged in the filter housing comprising a first (5,6,44,57) and a second (5,6,43,56) axially stacked cylindrical filter elements having different pore sizes, the first filter element being located underneath the second filter element; (e) a central outlet orifice (17,47) in the main-body through which the treated waste water exits the device with the assistance of a vacuum power from a remote vacuum generator; (f) two symmetrical inlets in the main body for evacuating dental surgery waste water comprising air fluid and solid particles, from the mouth of the patient with the assistance of the vacuum power; (g) a cyclone generator formed between the container and the external surface of the filter housing upstream of the filter housing that spins said air fluid and solid particles against the walls of said container; and (h) a spring valve (49,50) and air insert for each inlet to control the flow from the mouth of the patient into the device; i) a flow is formed going radially inwards into the first filter element having larger pores than the second filter element, then into the inner space of the second filter element having smaller pores and outwards through the second filter element toward the central outlet: or ii) two flows are formed, the first flow going radially inwards into the first filter element having smaller pores than the second filter element and then through the inner space of the second filter element towards the central outlet and the second flow going through a deflection wing between the filter elements which causes the particles to separate by particle size and then going radially inwards through the second filter element having larger pores and toward the central outlet.