Endodontic instrument for drilling
AssigneeFkg Dentaire S.A.
InventorOlivier Breguet
Life of this patent
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Abstract
An endodontic instrument for drilling root canals, in particular a flexible drilling instrument which comprises a working part and a securing end fitting intended for mounting the instrument in a mandrel of a contra-angle-type support provided with an electric motor used to drive an instrument clockwise. The casing of the working part is conical along its length and ends in a tip. The working part is provided with a spiral flute forming a ridge having a cutting edge. The drill bit, relief and cutting angles defined by the cutting edge can be varied along the length of the working part so that the instrument is particularly sharp in the area near the tip and so that the profile of the cutting ridge becomes progressively more blunt along the length of the instrument.
Claims11
1-10. (canceled)
A flexible endodontic instrument for drilling root canals, the instrument (10) having a longitudinal rotational axis and comprising:
- a working portion (11) terminating in a tip (13), at one extremity thereof, while an opposite extremity thereof terminating in a securing end fitting (12) which is attachable to a mandrel driven by an electric motor,
- the working portion (11) comprising at least one spiral flute (14) that defines at least one ridge (20),
- the at least one ridge (20) comprising an edge (24) with a peak (A) and exterior and interior sides (10a, 10b), respectively, located on either side of the edge,
- the peak (A) of the edge (24) being situated on a circle (E) whose center (O) is located on the longitudinal rotational axis, at different levels along the longitudinal length of the working portion (11), a cutting angle (A) at the peak (A) of the at least one flute (14) is defined as being the angle formed by a tangent (AY) to the peak (A) of the exterior and the interior sides (10a, 10b) of the at least one ridge (20), with a radius (A) from the peak (A) of the circle (E), and varying in width on at least one predetermined area of the working portion (11) and is one of negative, nil and positive,
- the cutting angle being negative when the tangent (AY) to the interior side (10a) of the ridge (20) is located on a side opposite to a tangent (AX) on an exterior side (10b) of the ridge (20) relative to a radius (AO) of the circle,
- the cutting angle being nil when the tangent (AY) to the interior side (10a) of the ridge (20) coincides with the radius (AO) of the circle,
- the cutting angle being positive when the tangent (AY) on the interior side (10a) of the ridge (20) is located on the same side as the tangent (AX) on the exterior side (10b) opposite the ridge relative to the radius (AO) of the circle,
- to define, along the ridge (20) of the at least one flute, either a scraping zone or a cutting zone, that are more or less active.
Dependencies are inferred from the claim text.