Abstract: The method and extractor relate to dentistry and are intended for extraction of metal instruments fragments from a root canal of the tooth, as these instruments may be broken and may get stuck here, for example, during endodontic treatment. According to the invention, two insulated metal electrodes assembled as a cylinder are inserted into the root canal until electric contact with the fragment to be extracted. Then electric current impulse is ran through the circuit formed by the first electrode, metal fragment and second electrode; the intensity and duration of the electric impulse shall be sufficient for welding of the fragment to the electrodes by means of heating at the contact points; this time a heating of the surrounding tissues remains at the physiologically acceptable level; afterwards the electrodes are extracted from the root canal together with the fragment. Depending on a clinical situation, electrodes of various size and configuration are used.

Abstract: A method of gas analysis and an ionization detector for its implementation provide a qualitative and quantitative analysis of impurities in a main (buffer) gas. The detector can operate in a wide range of gas pressures, up to atmospheric one. The identification of impurities is provided by analyzing the energy of electrons produced by the ionization of the impurity atoms or molecules in their collisions with long living atoms of a buffer gas or with monochromatic photons. The energy analysis of electrons produced in the collisions of impurities with metastable atoms in the afterglow plasma ignited between two plane electrodes is performed by determining the second derivative of electric current dependence on the voltage applied between the anode and the cathode. The electron energy can also be analyzed by positioning a grid between the anode and the cathode and by using an external ultraviolet radiation source to ionize the impurities in the equipotential space between the grid and the anode.