Abstract: A process for cleaning and/or shaping passages, comprising providing an optical fiber having a diameter sufficiently small to be introduced into the passage and having a free end provided with a radiation focussing element; introducing the free end of the fiber into the passage so that the focal point defined by the radiation focussing element is located adjacent the region to be cleaned or shaped; providing a liquid in the passage at the location of the focal point of the radiation focussing element; and supplying pulses of laser radiation to the fiber so that the radiation exits the fiber via the free end to provoke a cavitation of vapor at the interior of the irrigating liquid.

Abstract: A method and apparatus for cutting tooth tissue by generating laser radiation at a wavelength which is absorbed more strongly by hydroxyapatite than by water; producing a succession of pulses of the generated radiation with an energy level, pulse duration, and repetition rate selected to cut the tooth tissue without causing harmful side effects; and concentrating the radiation pulses on the tissue to a spot sufficiently small to cause cutting of the tissue.

Abstract: A method and apparatus for measuring the thickness of the dentin layer of a tooth in a patient, at a region where the dentin is exposed, during a dental treatment, by the steps of: establishing an electric voltage between the dentin at the region where it is exposed and a region of the patient's body spaced from the tooth to create an electric current flow through body tissue between those regions; monitoring the current flow to produce an indication of the electrical impedance between those regions; and converting the electrical impedance indication into an indication of the thickness of the dentin layer.

Abstract: A manually operated endodontic instrument composed of: an endodontic file; and a handle to which the file is immovably secured, the handle being formed to be gripped between the thumb and the index finger, having a longitudinal axis and an outer surface and including a central, longitudinally extending portion and first and second bulbous portions each joined to a respective longitudinal end of the central portion and each projecting laterally beyond the central portion, the handle being provided, at its outer surface, with at least two circumferentially spaced recesses extending longitudinally along at least part of the central portion.

Abstract: Drive head for an endodontic treatment instrument composed of a support body provided with a passage, an instrument support member having a longitudinal axis and mounted in the passage for movement relative to the body in the direction of the longitudinal axis, and drive components coupled to the instrument support member for inparting to the instrument support member alternating movements in the direction of the longitudinal axis, said instrument support member supports an andodontic treatment instrument in a manner to cause the instrument to move with the support in the direction of said longitudinal axis and to have a freedom of rotation about the longitudinal axis and relative to the support body and/or to cause the alternating movements in the direction of the longitudinal axis to have a variable amplitude.

Abstract: A clamp used for supporting a flexible sheet used in dental operations for isolating teeth has two jaws and a spring in the form of a bridge connecting the jaws, the improvement being that the clamp as a whole is made of a plastics material which is capable of resilient deformation and which is permeable to X-rays, for example polycarbonate.

Abstract: Drive head for an endodontic treatment instrument composed of a support body provided with a passage, an instrument support member having a longitudinal axis and mounted in the passage for movement relative to the body in the direction of the longitudinal axis, and drive components coupled to the instrument support member for imparting to the instrument support member alternating movements in the direction of the longitudinal axis, said instrument support member supports an endodontic treatment instrument in a manner to cause the instrument to move with the support in the direction of said longitudinal axis and to have a freedom of rotation about the longitudinal axis and relative to the support body and/or to cause the alternating movements in the direction of the longitudinal axis to have a variable amplitude.