Dentistry – Apparatus – Having motor or means to transmit motion from motor to tool
Reexamination Certificate
1999-05-21
2001-07-31
Manahan, Todd E. (Department: 3732)
Dentistry
Apparatus
Having motor or means to transmit motion from motor to tool
C433S125000, C433S142000
Reexamination Certificate
active
06267594
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the material-removing working of hard or soft tissues of the human or animal body or artificial parts thereof; and more particularly it concerns novel tools and instruments for such working.
2. Description of the Related Art
For the material-removing working of hard or soft tissues of the human or animal body or artificial parts thereof, such as e.g. protheses, there are already known various instruments and associated tools. Here, there may be involved both tools for a surface treatment and also tools for the making of a cavity or parting-off tools. Basically, one can divide the working movements of a tool of the kind being considered and associated instruments with drives into three groups, namely rotational movements, longitudinal movements and oscillation movements. A rotation movement takes place with conventional drills or millers and with circular saws. Longitudinal movements are employed for surface working, such as is the case with files, whereby the surface working may take place in a cavity, e.g. in a root canal, or at an outer surface, e.g. at the surface of a tooth or bone. Combinations of the above-mentioned movements are also possible and have also already been proposed for instruments and tools for the preparation of tooth root canals. A particular working movement is an oscillating movement, which may involve both a longitudinal movement, an orbital movement in a plane, e.g. orbital movements along a circular or elliptical path, or a three-dimensional movement. Significant features of such an oscillation movement are a high frequency and small amplitude.
Instruments and tools of the last mentioned kind are described for medical purposes in WO 96/14024.
SUMMARY OF THE INVENTION
The object of the invention is to so configure an instrument and a tool of the kinds indicated in the introduction that its scope of use is extended.
This object is achieved by means of a handpiece which contains a vibrator, a tool holding shaft connected to be vibrated by the vibrator and having an end which extends out from the handpiece and a tool connected to be vibrated in a given direction by the shaft. The tool is formed as a lamina which has extensive side surfaces which are separated by a narrow abrasive working surface which extends along a line. The direction of the line is independent of the direction of vibration.
The instrument in accordance with the invention is distinguished in that it has a tool body in the form of a lamina, which has the working surface on the narrow edge. In contrast to the known configurations the tool in accordance with the invention carries out the material removing working on a thin or line-like strip, the thickness of which is predetermined by the thickness of the lamina. As a result of this, the tool is not only efficient, because long incisions can be carried out with relatively little swarf or debris produced, but it is also possible after carrying out an incision to carry out one or more incisions running transversely of the previous incision or incisions so that a part of the object to be worked can be cut out. Thereby, the invention is based on the insight that due to the relatively slight magnitude of amplitude of the oscillations the lamina of the tool can be sunk into the object to be worked without the functioning of the tool being substantially impaired or prevented as is the case with conventional stroke-movement saws, which cannot be sunk into the object to be worked because thereby the relatively large stroke of the saw blade is prevented and the saw becomes incapable of functioning. In contrast thereto, the instrument in accordance with the invention, because of the small oscillation magnitudes of the tool body or of the lamina, remains unaffected even when the tool body or the lamina is sunk into the material being worked. For this reason the tool in accordance with the invention is suitable not only for the parting-off of an object which is smaller than the length of the tool, as is usual in the case of saw, but the tool body or the lamina may be smaller than the dimensions of the object and can also be sunk into the object to be worked.
The invention also relates to a medical or dental-medical instrument for the material-removing working of recess openings for implants in a body tissue of the human or animal body.
Previously, it was known to produce the recess openings for implants by means of a rotating tool and to emplace implants of corresponding cross-sectional shape into the recess openings.
This known manner of proceeding is disadvantageous because on the one hand rotating tools tend to go awry during the material-removing working and furthermore due to rotating tools there is predetermined a relatively large cross-sectional size for the receiving hole and for the implant. Furthermore, a rotationally symmetric cross-sectional form is disadvantageous, or restrictive of the range of use, for an implant with regard to the anchoring of the implant and the firmness of the bedding in. The above-mentioned difficulties arise in particular when a receiving opening extends only partly into the available jaw bone, e.g. when it at the same time extends into the tooth root pocket of a former tooth. Elongate oval implant cross-sections, as they correspond to the natural tooth root, e.g. in the upper jaw front tooth region, are not possible with rotational preparations. Also, kidney-shaped cross-sections, such as appear in the lower jaw tooth region, cannot be prepared rotationally.
Thus, in relation to another aspect, the invention has the object of so configuring an instrument for the material removing working of a receiving opening in a body tissue or a substitute material for receiving an implant, that a simple positioning of the receiving opening and/or a stable seating for an implant is attained.
This object is achieved by means of the a handpiece inside of which a high frequency vibrator is arranged, a tool located outside the handpiece, and a holding device connecting the vibrator to the tool for vibrating same, wherein the tool has the shape of a spatula having an abrasive narrow edge which forms an abrasive working surface. With this instrument in accordance with the invention no rotational movements take place. The tool body of the tool has, on its narrow edge facing in the direction of working of the tool, an abrasive working surface which due to the vibration drive of the instrument is abrasively effective and thereby removes the tissue evenly in a material removing manner. In this way, the receiving hole can be positioned in a simple manner in an exactly fitting way. Since with the instrument in accordance with the invention no rotational movements take place, there can be realised also cross-sectional shapes which deviate from a rotationally symmetric cross-sectional shape. Thereby it is of particular advantage to arrange a flattened or elongate cross-sectional form longitudinally of the object. This arrangement is very space saving and furthermore leads to a stable embedding of the implant in the tissue. These advantages apply in particular for jaw implants in the region of which, with regard to the anatomically factors and the presence of nerve channels, little space is available. With an arrangement of a non-circular cross-sectional form of the receiving hole in the buccolingual direction there can thus be gained a significant amount of space. Of particular significance is the gain in anchoring surface in particular when the anatomical conditions do not permit a deep preparation.
The invention relates also a tool for an instrument in accordance with the invention, with regard to the advantages which can be achieved thereby, attention is directed to the above-described advantages.
The configurations in accordance with the invention are suitable for both hard and soft tissue such as bone or flesh or skin.
This invention, in its more specific aspects, involves features which lead to simple, economically manufacturable, reliably functioning and
Fitzpatrick ,Cella, Harper & Scinto
Kaltenbach & Voigt GmbH & Co.
Manahan Todd #E.
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