US 3838517 A
The assembly includes a first surface adapted to be secured to a drill housing to serve as a reference plane and a second surface which serves as a seat to control the cut taken. A pair of screws couple through the reference member to carry the seat either towards or away from the reference plane, depending upon their manners of rotation. Both surfaces are apertured to accept a drill bit extending from a spindle in the housing, with the extension of the bit through the aperture in the seat controlling the depth of cut possible.
Description (OCR text may contain errors)
Oct. 1, 1974 1 COMBINATION DEPTH STOP AND GAUGE ASSEMBLY FOR A DENTAL DRILL Bruce T. Michnick, 33 Cherry Dr., Plainview, NY. 1 1803 Filed: Apr. 9, 1973 Appl. No.: 348,921
U.S. Cl. 32/27 Int. Cl. A610 1/10 Field of Search 32/67, 26, 27, 49, 29,
 References Cited UNITED STATES PATENTS 1,377,288 5/1921 Soresi 32/26 3,346,959 10/1967 Fridge 32/67 FOREIGN PATENTS OR APPLICATIONS 371,696 4/1932 Great Britain, 32/31 Primary ExaminerRobert Peshock Attorney, Agent, or FirmCharles 1. Brodsky  ABSTRACT The assembly includes a first surface adapted to be secured to a drill housing to serve as a reference plane and a second surface which serves as a seat to control the cut taken. A pair of screws couple through the reference member to carry the seat either towards or away from the reference plane, depending upon their manners of rotation. Both surfaces are apertured to accept a drill bit extending from a spindle in the housing, with the extension of the bit through the aperture in the seat controlling the depth of cut possible.
COMBINATION DEPTH STOP AND GAUGE- ASSEMBLY FOR A DENTAL DRILL.
FIELD OF THE INVENTION This invention relates to depth stop and gauge assemblies for drill constructions, in general, and to such assemblies for use in-root canal dentistry, in particular.
SUMMARY OF THE INVENTION As will become clear hereinafter. the assembly of the invention is especially attractive in that it affords a positive means of controlling the depth of cut made by a dental drill. In oneem'bodiment, an annular disk is employed, adapted for securement to a standard contraangle by a lock-screw collar which maintains the burr and its spindle holder in correct alignment. The annular disk also includes a pair of threaded holes, through which a pair of adjustable screws fit to mate with a second pair of aligned holes on an apertured plate. These screws carry the plate either towards or away from the disk depending upon their manner and degree of screw rotation. With the aperture of the disk and the opening of the plate both being in corresponding alignment to accept the burr of the spindle, the plate then acts as a seat to limit the penetration of the bit into a tooth being prepared. The precisedepth of cut to be.takenas determined from a grid X-ray, for example-can be preset by adjusting the separation between the bearing surface plate and the reference surface disk until the burr protrudes through both by the desired amount.
BRIEF DESCRIPTION OF THE DRAWING DETAILED DESCRIPTION OF THE DRAWING In the drawing, reference numeral represents a contraangle dental drill of a construction which is oftentimes used with a straight hand piece in working in the back areas of a patients mouth. For purposes of the present discussion, the contraangle 10 incorporates a spindle 12 which is geared to rotate and carry a drill bit or burr l4, usually of standardized length. A lock screw collar 16 bears against the spindle 12 to align and secure it substantially co-axially with the dental burr.
In accordance with one embodiment of the invention, however, the lockscrew collar 16 also serves to align and secure a depth stop and gauge assembly 20 to the contraangle 10, More specifically, an annular disk 22 of appropriate configuration is positioned intermediate the spindle 12 and the collar l6,such that adjustment of the collar to secure the spindle in place also serves to bear the annulardisk 22 against the contraangle housing. An apertured plate 24 also forms a part of the depth stop and gauge assembly 20, and is affixed with the annular disk 22 by means of two or more .fas-. teners-screws 25,26, for example. In particular, these fasteners fit through threaded holes 50,52 in the annular disk 22 and in the apertured plate 24 in a manner such that the disk 22 serves to carry the plate 24. With the pairof threaded holes 50,52 arranged co-axially with the-major dimension of both the annular disk 22 and the apertured plate 24and equally spaced on opposite sides of the holes therein, rotation of the screws 25,26 in the same direction will carry the plate 24 towards or away from the disk 22. Thus, by rotating the screws 25,26 clockwise, the apertured plate 24 can effectively be tightened by the screws towards the annular disk 22, whereas a counter-clockwise rotation of the screws 25,26 can loosen the apertured plate 24 away from the annular disk. With standardized length burrs protruding from the spindle through the holes in both the disk 22 and the plate 24, these screw rotations can effectively vary the amount'by which the burr extends beyond theapertured plate.
.As will be readily apparent, theapertured plate 24 can serve as a bearing or stop" surface to limit the depth to which the burrextends into a tooth being drilled, The annular disk 22, in this manner. serves as a reference plane, with respect to which the apertured plate 24 is adjusted to vary the depth of penetration desired. As will be seen, the depth of, penetration equals the sumof the length the burr l4 protrudes past the spindle 12 together with the thickness of the lock screw collar 16, less the length between the annular-disk 22 and the apertured plate 24.
In operation, an X-ray grid of the tooth being worked upon can be analyzed to determine the depth of penetration desired. The depth stop gauge assembly 20. c a n then be attached to the contraangle 1 0, and once the drill bit 14 is inserted, the screws 25,26 canbe rotated until the difference between these valuesis in corresponding relationship. Alternatively, for standardized length burrs and given thickness apertured plate annular disk and lock screw collar, it will also be seen that the degree of penetration can be .setbeforethe assembly is affixed to the contraangle by making those screw adjustments as are necessary in order that the burr extends beyond the plate by the required amount.
This manner of utilizing a precisely gauged, positive stop construction for use in contraangle drillingoffers a substantial improvement over present trial and error techniques in making root canal cuts. Oftentimes employed arrangements utilizing appropriate thickness rubber washers as bearing surfacesto limitthedepth of penetration suffer the disadvantage of notproviding a strong enough surface to limit morethan th e .desired extension, but also exhibit the tendency to revolve with the rotating drill, thereby reducing the stability and correctness of the overall operation. Withthe present invention, on the other hand, the adjustmentofthe screws to vary the separation between the annular disk and the apertured plate-of either metalor plastic fabrications-accurately restricts the extension of the burrinto the tooth being prepared, in. providing both depth stop and gauge operations.
While there has been described what is considered to be a preferred embodiment of the present invention, it will be, appreciated that modifications maybe made by those skilled in the art without departing. from the scope of the teachings herein of using both areference measuring surface and a separate bearing surface to control .the degree of cut takenby a dental -:drill. Its usage in post and pin reconstructions will-also be readily apparent.
What is claimed is: 1. A combination depth stop and gauge assembly for a dental drill comprising:
an annular disk adapted for securement to the housing of said drill and capable of accepting a burr extending from a spindle thereof;
an apertured plate co-axially aligned with said annular disk and configured to receive said burr from said spindle;
and means linking said annular disk and said apertured plate and arranged to move one of said disk and plate axially with respect to the other, for controlling the extent to which said burr protrudes through said annular disk and beyond said apertured plate, with said annular disk providing a reference measuring surface for the extension of said burr and with said apertured plate providing a separate bearing surface to control the degree of cut taken by said burr.
2. The combination of claim 1 wherein each of said annular disk and apertured plate incorporate thereon a plurality of threaded holes and wherein said lastmentioned means include a like number of adjustable screws linking said holes and rotatable therein to move said apertured plate towards and away from said annular disk.
3. The combination of claim 2 wherein each of said screws is rotatable in a clockwise direction to move said apertured plate towards said annular disk and lengthen the extent to which said burr protrudes through said disk and beyond said plate and wherein each of said screws is rotatable in a counter-clockwise direction to move said apertured plate away from said annular disk and shorten the extent to which said burr protrudes through said disk and beyond said plate.
4. The combination of claim 3 for use with a dental drill of the type wherein a lock screw collar is employed to maintain the spindle and burr in correct alignment relative to said housing and wherein said annular disk is secured to said housing by means of said lock screw