Dentistry – Apparatus – Tool bit
Reexamination Certificate
1999-01-05
2001-02-13
Lewis, Ralph A. (Department: 3732)
Dentistry
Apparatus
Tool bit
C408S226000
Reexamination Certificate
active
06186787
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to dental instrument. More specifically, the present invention relates to dental instrument with a pivotally arranged shaft and a head mounted to the shaft. The head is equipped with a plurality of cutting blades.
2. Background Information
In regulating teeth, it is a common measure in orthodontics to adhere so-called brackets to the teeth in place of braces. The brackets are subsequently connected with each other by means of wires. These brackets and wires apply forces to the teeth, which cause a change of position of the teeth. The brackets, which are mostly made of metal, are secured by means of specific synthetic materials. Of course, the brackets adhered to the tooth surface are to be removed when the orthodontic treatment is concluded. However, this also requires the removal of all adhesive residues from the tooth surface.
The problem of clearing away the adhesive or the residual adhesive from the tooth surface does not only exist for the orthodontist but also for the after-treating dentist whose main work is the removal of the residual adhesive. It is mainly during the removal of these residues where care must be taken that the tooth surface and the dental enamel are not being damaged.
The common rotating dental instruments known from the state of the art are only conditionally suitable for the removal of adhesive residues as the tooth surface and/or the tools will abrade the dental enamel. Also, the tooth may be damaged as a result of an inferior contact, e.g. when the residual synthetic material has been removed or when the tool slips.
In view of the above, there exists a need for dental instrument which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
SUMMARY OF THE INVENTION
The invention is based on the problem of providing a dental instrument of the initially mentioned kind which allows a simple and safe employment for reliably removing residual adhesive without damaging the tooth surface.
According to the present invention, a dental instrument with the features of the main claim solves the above-mentioned problem. The subclaims recite further advantageous embodiments of the present invention.
The present invention provides that the dental instrument that comprises a shaft and a head attached thereto. The head comprises a plurality of cutting blades attached thereto. The cutting blades are designed such that the blades have a clearance angle of 0°. A clearance angle of 0° as used herein means that the blade has an external surface, relative to the envelope curve of the dental instrument, by means of which the dental instrument can be propped onto the surface of the tooth or abutted against it. A rotating movement of the instrument thus leads to a substantially damage-free contact with the tooth surface. The beveled circumferential areas of the blades thus are supported by the tooth surface. On the other hand, residual adhesives projecting from the tooth surface are removed reliably.
According to the present invention, the areas of the blades are each provided with a clearance angle that can be of plane or partially cylindrical shape. In any case, the areas of the blades have sufficient surface for contacting the tooth surface without causing damage.
For processing and removing the residual synthetic material, it is favorable according to one of the embodiments of the invention that each of the blades has a negative cutting angle.
Moreover, the dental instrument of the present invention can comprise a plurality of blades, which are arranged substantially in parallel to each other. The shape of the head can be adapted to each condition of use. For example, the shape of the head can be realized as cylindrical, conical, ball-like or other shapes. The blades can run in a straight or screwed and/or spiral way.
The dental instrument according to the present invention can also be constructed such that it can be used for clockwise and counterclockwise rotation. It this case it might be favorable to make the blades symmetrically, relative to a plane running substantially through the rotational axis of the shaft. Of course, the symmetry is evident, in particular from individual vertical cuts through the rotational axis of the head of the dental instrument.
In order to guarantee an even and reliable removal of the residues of adhesive and/or synthetic material, it may be favorable to construct the blades equally. However, it is also possible to provide blades of different geometry at the circumference of the dental instrument. In particular, those types of blades have different cutting angles.
It is self-evident that with the dental instrument of the present invention, the dentist has to exert a certain contact pressure onto the surface of the tooth to be treated for removing the residual synthetic material. In particular larger amounts of synthetic material must be cleared away layer by layer. In order to create a contact possibility and in order to allow a well aimed exertion of the contact pressure, it may be favorable that the head comprises at least one annular, elastically deformable contact element projecting beyond the head's envelope curve. This allows the dentist to abut the contact element to the tooth surface before pressing the dental instrument against the tooth surface by elastically deforming the contact element, in order to remove the residual synthetic material.
It is particularly favorable when the contact element has the shape of a ring inserted into a circumferential groove of the head, e.g. like an O-ring. The circumferential groove can be provided at the front end or free end of the head or at any other section thereof. Of course, it is also possible to provide a plurality of circumferential grooves with a plurality of contact elements.
The contact element can have the shape of an elastic ring and it can be made from silicon or other synthetic materials. Due to the elasticity of its material, the contact element can be removed from the dental instrument in simple manner, e.g. for cleaning or sterilizing it.
These and other objects, features, aspects and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention.
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Danger Karl-Heinz
Danger Ralf
Gebr. Brasseler GmbH & Co. KG
Lewis Ralph A.
Shinjyu Global IP Counselors, LLP
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