| 摘要 |
A dental handpiece provided with a handle and a head on one end thereof in which a turbine rotates at high speeds and accommodates a cutting bur having an axial through opening to direct a preferably hygienic coolant directly through the cutting end of the bur, while the opposite end of the bur, on the interior of the head, is highly polished and absolutely flat for rotating engagement with one surface of a rotary liquid seal including a seal member of very hard substance in combination with a pliable compressible member engaging the opposite surface of the seal member, the combination being housed within a recess extending upwardly in a push button on the head or other finger-operated bur release mechanism on the head and having coaxial fluid openings communicating axially with the through opening in the bur and fluid passage in the push button leading from a fluid supply conduit in the handle. The fluid preferably consists of one or more of several chairside selectable pharmaceutical ingredients added to a coolant for discharge into a cavity being cut in a tooth by the handpiece.
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