(54) APPARATUS FOR THE DEEP MECHANICAL SYNDESMOTOMY OF:DENTAL CAVITIES(71) I, EUGENE LABORDE, of FrenchNationality, of 1 Place Carami, Brignoles,Var, 89170 France, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be described in 'and by the following statement: -This invention relates to an apparatus for the deep mechanical syndesmotomy of dental cavities.
An object of the invention is to enable the ligaments in dental cavities which con-, nect the tooth roots to the bone, to be cut in order to facilitate their extraction.
In ordinary syndesmotomy, use has hitherto been made of' hand inStrurnerits which only make it possible to, cut the gingival ligaments. Other known instruments, again manual, make it possible to remove some roots by slow pulling, but these operations are lengthy and require heavy pressure and -a very considerable effort by the operator.
According to the invention there is provided a cutting tool for carrying out deep syndesmotomy mechanically, separating and completely cutting ligaments connect- ing a tooth to its bone cavity, said cutting tool comprising:(i) a shank having an axis; - - (ii) means formed' on said shank formounting said'cutting tool on a toolholder;(iii) an elongate flexible blade. extending from - sa'id shank;(iv) a first cutting edge formed on oneside of said elongate blade; and(v) a second cutting edge -formed' on theother side of said elongate blade.
wherein said blade has a free endremote from -said shank and at least a portion of said blade is offset fromsaid shank axis, said blade beingsufficiently thin and flexible to enable it to penetrate into the dental cavity between' a tooth and the bone to cut all the ligaments connecting the roots of the tooth to the bone.
Advantageously, the means for fitting said cutting tool to said tool holder com- prises a tenon formed on said shank.
The blade is.preferably tapered in a direction. towards said free end thereof.
The free end of the blade may be rectili near or curved. - - Various shapes and configurations are en- visaged for the blades. In a first embodi- ment, the blade extends ,in, a .generally' straight line parallel to but spaced from said shank axis.
In an alternative embodiment, the. blade extends in a generally' curved line, said free end of said blade .lying on said shank axis, while a portion of said blade between said free end thereof and - said shank is offset from said shank axis.
The invention also provides the combina- tion of a cutting tool and a cutting tool.
holder, said cutting tool having:(i) a shank having an axis;(ii) first cooperating means formed on said shank for mounting said cuttingtool on said tool holder;(iii) an elongate flexible blade extendingfrom said shank;(iv) a first cutting edge formed on one eside of said elongate blade.;."' - (v) a second cutting edge formed onthe other side of said elongate blade, wherein said blade has a free ,endremote from said shank and ,at leasta portion of said blade.is offset froin said shank. axis; said blade being sufficiently thin and flexible to enable it to penetrate into the dentalcavity between a ,tooth and the .boneto cut all the ligaments. - connecting the roots of the tooth to the bone.
and said tool holder including :(vi) second coopernting means for., cooperating with said first cooperat,ing means for mounting said cutting:too') on - on said tool holder; and ,' -(vii) means for imparting to said cutting tool an alternating rotational,move- ment about said shank axis.
Preferably the -tool holder further ,in'-" cludes means for imparting to said cutting tool a reciprocatory percussion movement.
In an advantageous embodiment, the drive means is adapted to impart to said cutting tool an alternating rotational movement having an amplitude of substantially 45" about said shank axis.
The provision of thin (i.e. elongate) flexible blades of various shapes and configurations enables their penetration into the dental cavity space where, by a quick alternating rotational movement of small amplitude, they separate and then cut the ligaments.
Constructional embodiments of the invention will now be described, purely by way of example, with reference to the accompanying drawings in which: - FIGURE 1 shows the combination of a cutting tool and tool holder;FIGURE 2.shows a first embodiment of a cutting tool according to the invention:FIGURE 3 shows the cutting tool ofFigure 2, viewed in the direction III h Figure 2;FIGURE 4 shows a cutting tool according to a further alternative embodiment; andFIGURE 5 shows the cutting tool ofFigure 4 in use.
Figure 1 shows a cutting tool 1 according to the invention mounted in the chuck 22 of a conventional drill holder 2. The drill holder is of the type which will impart to the cutting tool 1 two modes of motion namely an upand-down motion in the direction of the doubleheaded arrow 21 and a limited rotation movement about the axis 23 of the cutting tool as shown by the double-headed arrow 20. The total amplitude of the rotational movement about the axis 23 is preferably 45".
Figures 2 and 3 show the detailed construction of one embodiment of a cutting tool according to the invention. The cutting tool comprises a generally cylindrical shank 4 having an axis 23, provided at one end with a tenon 3 or anchoring block suited to the chuck 22 of the drill holder 2 with which the tool is to be used.
At the other end of the cutting tool the shank 4 tapers at 30 to a relatively'narrow elongate flexible blade 5 tapering towards its free end. The blade 5 extends in a generally straight line parallel to, but spaced from, the shank axis 23.
The longitudinally extending side edges of the blade 5 are shaped into first and sec ond cutting edges 24, 25 which extend from the tapered portion 30 of the shank 4 to the free end or tip of the blade 1.
While the Figures show the shank 4 with a cylindrical configuration, any other ap propriate shape may be used.
-The orientation of the cutting portion 5 relative to the chuck 3 determines whether the blade is left-handed or right handed, the choice of blade to be used depending on the side of the tooth to be treated.
As is clear from Figure 2, the whole of the blade 5 is spaced from the shank axis 5. This ensures that, in use, the blade 5 will produce a curved cut through the ligaments about the tooth.
Figure 4 shows an embodiment of the invention in which the blade has a portion 27 intermediate its ends which extends in a generally curved line and is spaced from the axis 23 of the shank 4, while the tip 26 in this case lies on the shank axis. The advantage of this construction can be seen from Figure 5 which shows, in dashed lines, a tooth 28 held in the bone 29 of the patients jaw by its root 31. The blade 5 is inserted into the neck between the tooth root and the bone. The movement imparted to the blade 5 by the drill head 2 first separates the root from the bone facilitating its deep penetration with dislocating and cutting lateral shearing. The operator makes almost no effort and extraction is mechanised.
The shaped blade 5 allows an envelop- ing trajectory facilitating the penetration of the tip 26 into the bottom of cavities to detach pieces of unremoved root from the ligaments holding them.
WHAT I CLAIM IS:- 1. A cutting tool for carrying out deep syndesmotomy mechanically, separating and completely cutting ligaments connecting a tooth to its bone cavity, said cutting tool comprising:(i) a shank having an axis;(ii) means formed on said shank formounting said cutting tool on a toolholder;(iii) an' elongate flexible blade extendingfrom said shank;(iv) a first cutting edge formed on oneside of said elongate blade, and(v) a second cutting edge formed onthe other side of said' elongateblade, wherein said blade has a freeend remote from said shank and atleast a portion of said blade is offsetfrom said shank axis; said bladebeing sufficiently thin and flexibleto enable it to penetrate into thedental cavity between a tooth andthe bone to cut all the ligamentsconnecting the roots of the tooth tothe bone.
2. A cutting tool according to Claim 1 wherein said means for fitting said cutting tool to said tool holder comprises a tenon formed on said shank.
3. A cutting tool according to Claim 1, wherein said blade is tapered in a direction towards said free end thereof.
4. A cutting tool according to Claim 3, wherein said free end is rectilinear.
5. A cutting tool according to Claim 3, wherein said free end is curved.
6. A cutting tool according to Claim 1, wherein said blade extends in a generally straight line parallel to but spaced from said shank axis.
7. A cutting tool according to Claim 1, wherein said blade extends in a generally curved line, said free end of said blade lying on said shank axis, while a portion of said blade between said free end there of and said shank is offset from said shank axis.
8. A device for carrying out deep syndesmotomy mechanically, separating and completely cutting ligaments connecting a tooth to its bone cavity, comprising a cutting tool and a cutting tool holder, said cutting tool having:(i) a shank having an axis;(ii) first cooperating means formed onsaid shank for mounting said cuttingtool on said tool holder;(iii) an elongate flexible blade extendingfrom said shank;(iv) a first cutting edge formed on oneside of said elongate blade;(v) a second cutting edge formed on theother side of said elongate blade,wherein said blade has a free endremote from said shank and at leasta portion of said blade is offset fromsaid shank axis; said blade beingsufficiently thin and flexible to enable it to penetrate into the dentalcavity between a tooth and the boneto cut all the ligaments connectingthe roots of the tooth to the bone.
and said tool holder including:(vi) second cooperating means for cooperating with said first cooperatingmeans for mounting said cuttingtool on said tool holder; and(vii) means for imparting to said cuttingtool an alternating rotational movement about said shank axis.
9. A device according to Claim 8, wherein the tool holder further includes means for imparting to said cutting tool an axial reciprocatory percussion movement.
10. A device according to Claim 8, wherein said rotational movement has an amplitude of substantially 45" about said shank axis.
11. A cutting tool according to Claim 1, substantially as hereinbefore described.
12. A device according to Claim 8, substantially as hereinbefore described.
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