WO2011131357A2

WO2011131357A2 - Surgical tool, in particular for drilling bone for inserting a dental implant

Info

Publication number: WO2011131357A2
Application number: PCT/EP2011/002013
Authority: WO
Inventors: Herbert R. Hatzlhoffer
Original assignee: Hatzlhoffer Herbert R
Priority date: 2010-04-23
Filing date: 2011-04-20
Publication date: 2011-10-27
Also published as: WO2011131357A3; DE102010018245A1

Abstract

Surgical tool (1) for machining bone, in particular for drilling bone for inserting a dental implant, comprising a tool shaft (2), which is embodied to be mounted into a rotatable tool holder and has a channel (3) for passing through a cooling or rinsing liquid, a treatment part (4) that can rotate about an axial rotational axis (C), can be driven by the tool shaft (2) and is arranged at the proximal axial end of the tool shaft (2), and a guiding element (5) that extends in the axial direction of the tool (1), is arranged at the proximal axial end of the treatment part (4) and designed for insertion into a pilot bore. The treatment part (4) is axially moveable relative to the guiding element (5) and the tool (1) has a spring element (6) that generates a restoring force that moves the treatment part (4) in the proximal direction, wherein the treatment part (4) is axially moveable against the restoring force between an extended and compressed position.

Description

Surgical tool, in particular for drilling bone for the insertion of a dental implant

The invention relates to a surgical tool for processing bones, in particular for drilling bones for the insertion of a dental implant.

The tool according to the invention can be used in all areas of bone surgery. However, it can also generally be used in the machining of any material other than bone, for example wood or plastic. It is described below without restriction of generality by means of the example of implant bores for maxillofacial surgery.

Dental implants are foreign bodies inserted in the jawbone. The field of dentistry, which deals with the implantation of dental implants in the jawbone, is referred to as implantology. Due to their usefulness as carriers of dental prostheses, dental implants assume the function of artificial tooth roots. To drill the holes for placing the dental implants in the jaw, a drilling template is used.

In the meantime, the technique of having a lost tooth by a dental implant and a dental prosthesis attached thereto Enforced bridge replaced. One uses an implant made of ceramic material or metal, anchored in the bone. This serves as an implant root on which the artificial dental crown is attached. For this purpose, a hole for the implant root must be inserted into the jaw at the site of the lost tooth. Since the artificial tooth crown harmoniously integrate into the row of teeth and the implant root should have the largest possible diameter for better bite pressure recording and the bone supply in the jaw is limited, the position and angular orientation of the hole must be exactly precalculated and adhered to.

To ensure this, a drilling template is usually first created, which has at the predetermined location a angularly adjusted drill sleeve whose inner diameter corresponds to the diameter of a pilot drill for the jaw bore. The surgical template is worn by the patient drilling the pilot hole. This template can be made using a patient's jaw model or purely from radiographic or CT-acquired data. Furthermore, the necessary information for the determination of the direction of drilling information about the extent of the jawbone are obtained by means of a computed tomography, with different sectional views are possible through the jaw. Other methods used to measure the jaw for making a surgical jig are e.g. the so-called bone mapping, the bone measurement with a probe or other measuring methods.

Surgical templates are thus auxiliary devices in order to make it easier for the implantologist to introduce a bore into the jawbone of a patient into which the implant is to be inserted. The drilling template has a bore hole created on the jaw model, which serves as a guide for the bore when inserting the bore or pilot bore into the jawbone. serves. It enables minimally invasive procedures. The drill hole should have the correct position and angular position.

Before introducing an implant into a bone, the bone material is first processed with special surgical tools. Frequently, first a pilot hole, the so-called pilot hole, made with a relatively thin drill, in which the preparation depth is ensured by depth limiting elements. Thereafter, the pilot hole is drilled out with the aid of a so-called shape drill and thereby receives the necessary shape for the implant. In a next step for the preparation of the bone, the mold bore is threaded. For this purpose, a tap is screwed into the hole. The form drill thus serves to drill the hole in the jaw, after the pilot hole was performed with a pilot drill (and possibly the guide sleeves of a drilling template). When drilling with the form drill usually no guide sleeve is used. The guide sleeves are screwed, for example, in the drilling template and are preferably bone-supported. For this the gums are removed, e.g. cut or punched, and the guide sleeve is screwed into the surgical template until the bone contact.

When drilling with the form drill, it can come to the conventional machining tools to considerable difficulties. There is always the risk that you leave the given drill hole during processing and affects surrounding bone material. This is especially true in the preparation of jawbone, because the implant bore extends into the porous sponge-like bone material of the cancellous bone and the tool may penetrate into the cavities of the bone tissue. This would severely affect the patient's jaw and possibly even the use of implants impossible.

Another danger is that the work goes beyond the specified depth of the bore, breaking through the wellbore, affecting both jaw material and nerves.

Common implant tools require expensive drill sets and other instruments during surgery. For example, diameter-graded osteotome sets are used which are shaped differently for the anterior and posterior regions.

In the prior art, EP 1 304 087 A2 discloses a surgical tool for preparing bones, in particular for processing bones for inserting a dental implant

a tool shank, which is designed to be clamped in a rotatable tool holder and has a channel for passing a cooling or rinsing liquid,

- A rotatable about an axial axis of rotation machining part which is drivable by the tool shank and disposed at the proximal axial end of the tool shank, and

a guide element extending in the axial direction of the tool, which is arranged at the proximal axial end of the machining part, axially movable relative to the machining part and to

Insertion is formed in a pilot bore and on its surface one or more axially extending rinsing grooves for guiding the cooling or rinsing liquid comprises.

After the pilot drilling, the final drilling (so-called "finish drilling") takes place with such a form drill before the insertion of the Implant body in the jaw. The known form drill, which could also be referred to as a telescopic drill, has the property that it is guided by the attached to the active cutting, telescopically extendable and retractable in the axial direction guide element, which disappears under pressure into the interior of the drill head. In use, the drill bit is pushed into the pilot hole without tilting it. When the guide member reaches the bottom of the pilot hole, it pushes against the spring force into the drill head until it encounters a stop. If the guide element protrudes from the drill head in this stop position, for example by 0.5 mm, and is not cutting, the drill head remains in its drilling motion in the blind hole of the pilot hole and can no longer be performed actively. The "finish bore" is thus carried out.

While good results could be obtained with this known tool, it has been found in practice that both the cooling of the processing part by the cooling fluid and the removal of the bone chips, tissue and blood from the drilling site during processing are not optimal and improved should.

An improved tool in this respect is known from WO 2009/135514 AI. However, it has been shown that even with this tool too much heating of the bone during drilling can occur. Bone and tissue care is very important when drilling bone. The initial temperature is 37 ° C, and drilling should not cause temperatures above 41 ° C, otherwise permanent damage to the drilled bone and embedded nerves in the area of the bore may result in inflammation and, often, after a few months Implant leads.

The present invention is therefore based on the object to provide an improved surgical tool, with the tissue preserving bone material can be machined without the tool breaking out of the bore channel or piercing the bore channel, allowing for improved cooling and removal of bone chips, tissue and blood. It should also be possible to realize a guide and a hole depth stop and allow any cutting geometries.

The object is achieved by a surgical tool with the features of claim 1. Preferred embodiments will become apparent from the dependent claims and the following description with accompanying drawings. It is noted that the features described in the dependent claims and the following description with associated drawings can be applied not only in the invention but also in generic tools according to the preamble of claim 1.

A surgical tool according to the invention for processing bones, in particular for drilling bones for inserting a dental implant, thus comprises a tool shank, which is designed to be clamped in a rotatable tool holder and has a channel for passing a cooling or rinsing liquid, one around an axial one A rotary axis rotatable machining part, which is drivable by the tool shaft and disposed at the proximal axial end of the tool shaft, and extending in the axial direction of the tool guide member which is arranged at the proximal axial end of the machining part and adapted for insertion into a pilot hole, and has the peculiarity, the machining part is axially movable relative to the guide element and the tool has a spring element which generates a restoring force, which moves the machining part in the proximal direction, wherein the processing tion part against the restoring force axially between a rebounded and a sprung position is movable.

The terms proximal and distal are used in the usual meaning in medical technology. Proximal means close to the body, distal to the body, away from the body. Accordingly, in the present context of a bone working tool, the proximal end of the tool is formed by the tool tip facing the machined bone and the distal end of the tool by the tool shaft, the proximal direction points from the tool shaft to the tool tip and the distal direction from the tool tip to the tool shaft.

It has been found that optimal bone machining is possible with such a surgical tool with a telescoping, ie axially displaceable machining part. This is due to the fact that the machining part is sprung axially and thus, by exercising a small proximal feed force with the tool, it is possible for the machining part and thus the tool to work slowly into the machined material. The tool shank and the guide element form a unit oriented in the axial direction relative to one another, along which the machining part (telescopically) can be displaced axially between its spring-loaded and spring-down position. Thus, no axial movement takes place between the tool shank and the guide element. The tool shank can be rotatable relative to the guide element and the machining part can be rotated relative to the guide element. The guide element does not have to be able to rotate or rotate in the borehole, but it can rotate. In a first embodiment, the machining part can rotate about the guide element, wherein the guide element remains in its position without its own rotational movements and only the machining part rotates. carries out movements. In another preferred embodiment, the guide member with the processing member is rotatable, for which purpose the Füh ^¬ approximately element rotationally fixed to the machining part or the tool shank is connected.

The processing part intersects in principle axially pulsating spring-loaded against the spring bias of the spring element, wherein it can oscillate in the proximal and distal directions back and forth and the maximum deflections are given by the rebounded and rebounded position. This prevents too much pressure from being applied to the tool or the bone, since the feed force exerted on the bone by the machining part is not determined by the user of the tool but by the strength of the spring element. The heat development during processing is thereby greatly reduced. Such a spring element may for example be a compression spring with a spring force of about 0.5 N to 2.0 N.

However, if the feed force of the tool is increased by the user exerting greater proximal pressure therewith, the working member may assume the maximum rebound position in which, for example, the spring member goes to block or otherwise stop between the tool shank and the working member Machining part limited to the tool. In this case, the spring action of the spring element is canceled and with the tool can be drilled with the larger, predetermined by the user pressure.

The machining part or the tool can be made in any shape (geometry), for example cylindrical, conical or conical, and be designed for example as a tap or as a milling cutter. A preferred embodiment is a drill, similar to a twist drill or countersink. In this case arises Drill with an axially telescoping or pulsating drill bit, wherein the drill bit is formed by the machining part.

The machining part preferably has an outer diameter between 1.8 mm and 15 mm, preferably between 2.0 mm and 12 mm, particularly preferably between 2.5 mm and 10 mm. The lower limit results from the requirement that the remaining wall thickness for the cutting edge must be large enough. The upper limit results from convenient areas of general orthopedic applications.

According to an advantageous feature, the machining part thus has at least one cutting edge at its proximal end. The term drilling refers to machining processes for the production of through holes or blind holes. These methods differ in particular in the type of tools used and in the drilling depths to be machined. The particular problems of drilling are avoided by the invention. The falling to zero cutting speed in the drill center is unproblematic due to the pilot hole and the penetrating guide element. The more difficult removal of the chips with increasing drilling depth is ensured by flushing. The unfavorable heat distribution in the interface is improved. With a drilling tool according to the invention, it is possible to make a bore in the pilot bore of a bone in a single and gentle drilling process with the desired final diameter, without requiring successive drilling with drills of increasing diameter in order to overheat the bone avoid.

In the prior art, cutting geometries from the metal sector are used in bone drills, in particular twist drills with helically extending flutes. A usable in the context of the invention or in a generic tool, novel, improved Cutting geometry is that the proximal cutting edge of the processing part has a concave free surface. In this case, the machining part (the drill bit) has an "inverse" active cutting edge, in which the radially outer edges of the cutting edge are more proximal than the core of the machining part, ie the core of the machining part is arranged more distally than the radially outer edges of the cutting edge is. The proximal end of the machining part thus has a depression (negative tip angle) toward the axis and in the distal direction and does not protrude proximally from the tip tip of a conventional twist drill towards the axis.

The tool cutting edge on the machining part (the drill bit) results along the line on which the rake face and the free face meet. In contrast to the classical cutting geometry, according to a preferred feature, the free surface is concave, resulting in an initially small wedge angle at the cutting edge (good cutting property). Due to the concave shape of the free surface, the wedge angle increases in the further course (high stability). The rake angle of the tool can be positive or negative.

According to a further advantageous feature, it can be provided that the machining part has at least one ejection channel serving as a chip space, which is arranged on the lateral surface of the machining part and runs essentially axially. The chip space is also referred to as a flute and is a groove in a drill body that provides a major cutting edge at the interface with the main flank, thereby allowing the removal of chips from the wellbore. In contrast to the helical flute of a conventional twist drill, the flute preferably extends substantially axially, ie the flute has no or only a minimal swirl pitch, wherein the swirl angle between -15 ° and + 15 °. The at least one discharge channel can have parallel longitudinal edges. Preferably, however, it is open at an opening angle of up to 15 ° in the distal direction. In this case, one of the longitudinal edges of the discharge channel, preferably the leading edge leading in the direction of rotation, can be parallel to the axis of rotation of the tool. In this case, the trailing edge of the discharge channel, in particular the rake surface of a secondary cutting edge, trailing in the direction of rotation is inclined by the opening angle against the axis of rotation of the tool. The opening of the discharge channel in the distal direction prevents the abgespante bone material adhered to the drill, so that it is safely conveyed out of the wellbore.

A further advantageous feature may be that the machining part has at least one secondary cutting edge with very little or no swirl pitch. The secondary cutting edge is preferably formed on the rake face of the chip space. In contrast to the screw-shaped secondary cutting edge of a conventional twist drill, the secondary cutting edge preferably extends essentially axially, ie. the minor cutting edge has no or only a minimal swirl pitch, the swirl angle being between -15 ° and + 15 °.

In a further advantageous embodiment, it can be provided that the at least one secondary cutting edge is designed as a grater. Reaming is one of the finishing processes, improves the quality of the hole and corresponds to drilling with a small chip thickness. The processing part is used in this training as a single or multi-bladed grater or reamer. The processing part cuts with its proximal end of the bottom of the borehole and rubs with its outside the inner wall of the borehole. Preferably, two opposing reamers are provided. Advantageously, it can be provided that the guide element or at least the insertable into a pilot hole proximal part of the guide element is formed like a pin. Further, it is advantageous if the guide element or at least the insertable into a pilot hole proximal part of the guide element is not designed for chip removal of bone, in particular not designed for drilling, cutting or milling. A non-cutting guide ensures that the user can drill a perfectly round hole without deviating from the pilot hole in terms of depth and / or angle.

The outer diameter of the guide element is advantageously as large as, slightly larger than or slightly smaller than the inner diameter of the pilot hole. Appropriate values are between 0.5 mm and 6.0 mm, preferably between 0.8 mm and 4.0 mm, particularly preferably between 1.0 mm and 2.5 mm.

A particularly advantageous embodiment may consist in that the maximum machining depth of the guide element can be specified. This ensures that the machining parts can not penetrate beyond the predetermined hole in the bone. The processing space for the rotatable machining part is specified exactly and there is no risk of lateral deflection or exceeding of the bore depth. Sources of error during processing are thus largely excluded.

When the guide element dictates the maximum working depth of the machining part in the borehole, this brings many advantages. So do not have to be laboriously attached so-called depth stop rings above the drill. Furthermore, there is an automatic processing stop in the desired processing depth and it must not be on a length scale, the penetration depth before or during the be measured throughout the machining process. By the guide element, a maximum machining depth can also be specified if the machining part is not completely penetrated into the hole. This is not possible when using conventional depth stop rings, as they usually have to be fastened above the machining part and thus would not come to a stop at the bore mouth.

The maximum machining depth can either be specified by the guide element according to production or, if necessary, adjusted by the user according to his wishes on the tool itself. The maximum machining depth can be selected arbitrarily, so that, for example, only the upper part of the bone bore is machined or the machining takes place almost to the end of the bore.

If the maximum machining depth is specified by the guide element, it is expedient, for example, if the machining depth can be predetermined by a stop. In this case, the machining part can only be displaced axially up to this stop in the rebound position on the guide element. An editing beyond the stop is then not possible.

Accordingly, in the rebound position of the machining part, the guide element advantageously protrudes at the proximal end of the machining part, relative to the cutting line of the proximal end of the machining part. The projection by which the tip of the guide element protrudes proximally from the active cutting edge, for example from a drill head or a drill bit, for example by a value between 0.1 mm and 1.0 mm, preferably between 0.2 mm and 0.5 mm, then also has a stop function that prevents the drill from drilling deeper when the pilot hole was drilled deep. The drilling process ends in the blind hole of the pilot hole. According to a further advantageous feature, it is proposed that the guide element has on its surface at least one axial Spülungsnut, axial flattening, axial bevel, an axial incision or an axial surface grinding, by means of the cooling or rinsing liquid toward the proximal end of the processing part and / or is conductive to the proximal end of the guide element. The liquid then flows through the channel in the tool shank as well as the space between the flushing groove or the like and the inside of the machining part to the proximal end of the guide member. The cooling or rinsing liquid thus flows in the flushing grooves or the like, preferably in the direction of the proximal end of the guide element.

The advantage of flattening, chamfering or surface grinding over a narrow groove or narrow incision is that a larger cross-section is available in the wellbore for the flow of cooling fluid, which can better counteract overheating and better clean out the bone chips so that there is less clogging.

Advantageously, the channel may continue from the tool shank in an axial blind hole or hole in the distal end of the guide member, and then be connected at a certain depth by a transverse bore in the guide member to the flushing groove or the like. The guide member thus has a bore which carries the channel out of the tool shank to guide and channel around the flushing or cooling fluid to a transverse bore. Due to the transverse bore, the liquid can escape from the interior of the tool shank into the interior of the processing part. The guide element preferably has in the places or sides where the transverse bore exits or the transverse bores emerge, via the flushing groove or the like, as explained above. Between the inner diameter of the machining part and the bottom of the flushing groove or the like, for example the ground surface of a bevel, the liquid can escape in the direction of the proximal end of the machining part, for example an active proximal cutting edge of a drill bit or a drill bit.

Advantageously, it may further be provided that the tool and the flushing groove or flattening, axial chamfer, the axial cut or axial surface grinding are formed such that the exit point at which exits the cooling or rinsing liquid from the channel in the Spülungsnuten, in Area of the transition between the proximal axial end of the machining part and the guide element is arranged. This has the advantage that the fluid used for cooling or flushing emerges directly at the proximal cutting edge of the machining part, and not at the tip of the guide element at the bottom of the pilot bore. This results in the advantage of better cooling of the cutting edge and thus a jaw- and tissue-preserving machining or drilling operation, because the cooling liquid does not emerge first through an opening located at the proximal end of the guide member, through the narrow gap between the proximal end of the guide member and the the bottom of the pilot hole adjacent thereto must flow and must flow back through the flushing grooves to the proximal end of the machining part, but can exit directly at the proximal end of the machining part.

Accordingly, it can advantageously be provided that the guide element has no continuous inner channel for passing the cooling or rinsing liquid or for its exit from the tip of the guide element or the guide element at its proximal end no opening from the cooling or rinsing liquid exits. The Flushing grooves may advantageously extend to the proximal end of the guide element.

A better rinsing of bone chips, tissue parts and blood results from the fact that the flow is directed radially from the inside out and thus transported away the removed bone chips from the drilling point radially outward. As a result, clog the outlets of the cooling channels and the cooling channels or Spülnuten even less.

A further feature which is advantageous in this context may be that the surgical tool and the flushing grooves are designed in such a way that the cooling or flushing liquid flows in the flushing grooves in the direction of the proximal end of the guide element. The guide element thus has one or more axially extending outer grooves, which may also be referred to as slots or grooves, in which the cooling fluid flows in the direction of the proximal tip of the guide element. On the other hand, in the prior art, the cooling liquid exits at the proximal tip of the guide member and returns to the outside of the guide member in the flushing grooves. In the invention, therefore, the flow of the cooling or rinsing liquid in the flushing grooves of the guide member is directed proximally, whereas it is directed distally in the prior art.

Accordingly, it may be provided in an advantageous embodiment that the guide element has no channel for passing the cooling or rinsing liquid and / or that the guide element has no opening at its proximal end, emerges from the cooling or rinsing liquid.

An additional advantageous embodiment may be that the sum of the cross-sectional areas of the flushing grooves or the like in the guide element at least as large as the cross section of the channel is in the tool shank. The advantage here is that a reduction of the flow cross section for the flow of the cooling or rinsing liquid is prevented by a cross-section narrowed transition from the channel into the flushing grooves and thus a reduction of the coolant flow.

The tool and its components can be made of any suitable material. One, several or all parts of the tool shank, the machining part and the guide element or the cutting can be made of steel, industrial steel no. 1.4301, 1.4303, 1.4305, 1.4034 or 1.4197, high-speed steel (HSS, high-alloy steels), which as main alloying elements tungsten, molybdenum, vanadium , Cobalt and chromium), conventional high-speed steel, powder-metallurgy high-speed steel, sintered material, hard metal (uncoated or coated), ceramics, cutting ceramics, mixed ceramics, silicon nitride ceramics, corundum, titanium, titanium nitrite, titanium nitride, zirconium, zirconium oxide or boron nitride.

According to a preferred further feature, however, it can be provided that the tool has a plastic part which consists of a plastic which deforms at a temperature which is below the sterilization temperature of the tool. Usually, the sterilization temperature is 137 ° C, so that it is advantageous if the plastic part deforms at a temperature and thus destroys the plastic part, which is close below, for example, about 130 ° C. As a result, the tool becomes a disposable product which can be used, for example, only in one implant bore or multiple implant bores simultaneously performed on a patient because sterilization is visually reused for reuse in another patient visible deformation or destruction of the plastic part is displayed. The tool is factory-sterilized, sterilized by, for example, radioactive irradiation, and is not reusable after use by standard user thermal sterilization and thus protected against reuse. The hygiene is thus significantly improved. In fine threads, crevices, grooves, etc., in the tool, bone chips, pieces of tissue, and blood may collect during drilling, which are insufficiently removed by cleaning and thermal sterilization. Therefore, a tool should only be used as part of an operation on a single patient.

In a further embodiment, it may be provided that the plastic part is a cap which is arranged above or around a spring element containing the spring chamber, that it penetrates into the spring chamber during deformation. As a result, a possible thermal sterilization is not only made visually visible, but the melting of the plastic blocks the spring element in the spring chamber and makes the tool unusable.

The plastic part can also perform other functions. For example, it can be designed with different tools in different colors, so that it forms a color coding for the tools. Furthermore, the plastic part in production can represent a cheap, simple and quick way to assemble one or more parts of the tool, in particular tool shank and guide element, by means of a plug connection by means of the plastic part or in the plastic part. If the tool shank and the guide element do not form an integral part but are assembled together, however, the parts can also be connected in other ways, for example by means of a screwed threaded connection. The invention will be explained in more detail with reference to embodiments shown in the figures. The peculiarities described therein may be used individually or in combination with each other to provide preferred embodiments of the invention or a generic tool. Show it :

1 shows a side view of a first drill according to the invention with a cylindrical drill head in the rebound position, FIG. 2 shows a first side view of a second drill according to the invention with a conical drill head in the rebound position, FIG. 3 shows an axial longitudinal section to FIG.

FIG. 4 shows a further axial longitudinal section to FIG. 2,

Figure 5 is a second side view of Figure 2 in the sprung

Position,

Figure 6 is a third side view of Figure 2 in the sprung

Position,

FIG. 7 is a side view of the processing part of FIG. 6;

FIG. 8 is a side view of the processing part of FIG. 2,

FIG. 9 is a side view of the processing part of FIG. 5;

FIG. 10 is a simplified perspective view of the processing part of FIG. 2,

FIG. 11 shows a sectional view of FIG. 7,

FIG. 12 shows a sectional view of FIG. 8,

FIG. 13 is a simplified perspective view of the processing part of FIG. 2,

Figure 14 is a perspective view of a third invention

Drill with partially cylindrical drill head in the spring-loaded position,

FIG. 15 is an exploded view of FIG. 14;

FIG. 16 a longitudinal section to FIG. 14,

17 shows a first side view of FIG. 14 in the rebound position, FIG. FIG. 18 shows a longitudinal section AA to FIG. 17,

19 shows a second side view of FIG. 14 in the spring-loaded position, FIG.

FIG. 20 shows a third side view of FIG. 14 in the spring-loaded position,

FIG. 21 shows a longitudinal section B-B to FIGS. 19 and 20,

FIG. 22 is a plan view of FIG. 17;

FIG. 23 shows a section C-C to FIG. 17,

FIG. 24 shows a section D-D to FIG. 20,

FIG. 25 is a plan view of FIG. 19;

FIG. 26 shows a first side view of the processing part of FIG. 14,

FIG. 27 is a second side view of the processing part of FIG. 14;

FIG. 28 shows a third side view of the processing part of FIG. 14

FIG. 29 shows a longitudinal section A-A to FIG. 26,

FIG. 30 shows a detail B of FIG. 26,

FIG. 31 shows a plan view of FIG. 26,

FIG. 32 shows a detail of FIG. 31,

Figure 33 is a section C-C to Figure 27 and

FIG. 34 shows a section F-F to FIG. 27.

FIG. 1 shows a first exemplary embodiment, FIGS. 2 to 13 show a second exemplary embodiment, and FIGS. 14 to 34 show a third exemplary embodiment of a tool 1 according to the invention in the form of a drilling device for drilling a hole in a jaw for the insertion of a dental implant shown. Corresponding elements are each denoted by the same reference numeral. The drilling apparatus comprises a tool shank 2 which is designed for clamping into a rotatable tool holder and has a channel 3 for passing a cooling or rinsing liquid, and a machining part 4 rotatable about an axial, clockwise rotating rotation axis C, which can be driven and driven by the tool shank 2 the proximal axial end of the tool shank 2 is arranged. The embodiment of Figure 2 corresponds to the first embodiment of Figure 1, with the difference that the machining part 4 is not conical, but cylindrical. The embodiment of Figure 14 corresponds to the embodiment of Figure 2, with the difference that the machining part 4 is partially conical or double conical and has an outside diameter cutting edge.

The machining part 4 may be, for example, a drill head or a drill bit. Furthermore, the tool 1 comprises a guide element 5 extending in the axial direction of the tool 1, which is arranged at the proximal axial end of the machining part 4 and designed for insertion into a pilot hole.

In the distal end of the tool shank 2, which is clamped in a tool holder, it is, for example, a DIN-standard part or finished part. The tool shank 2 is set in rotation after being clamped in a drive (not shown), for example an angle piece, and transmits the rotational movement to the machining part 4, which rotates about the axis C as a rotating machining part. The machining part can be fastened on a support, for example a drill head or drill bit carrier. The transmission of the rotational movement of the tool shaft 2 on the machining part 4 can be done for example by a positive connection in the direction of rotation.

The machining part 4 is axially movable relative to the guide element 5 (and to the tool shank 2). Corresponding sectional views of the structure of the tool 1, by which this is made possible, are shown in Figures 3 and 4. In this case, the tool 2 as a spring element 6, a coil compression spring which generates a restoring force which moves the machining part 4 in the proximal direction, wherein the machining part 4 against the restoring force axially between a in the figures 2 to 4 dar- Asked rebound and a deflected position shown in Figures 5 and 6 is movable. The spring element 6 thus presses with its restoring force the machining part 4 in the proximal direction in the rebounded position, and by a counter-pressure on the proximal end of the machining part 4 in the distal direction, the machining part 4 can be moved in the distal direction to a sprung position.

It is thus provided between the tool shank 2 and machining part 4, an axially acting spring element 6, which presses the machining part 4 along the guide member 5 in the proximal direction. The tool 1 thus has a spring element 6 which generates a restoring force which moves the machining part 4 in the proximal direction relative to the tool shaft 2, wherein the machining part 4 is axially movable against the restoring force. The advantage is that the machining part 4 can oscillate during drilling in the axial direction.

The spring element 6 is seated at its one end on a spring seat of the machining part 4. At its other end sits the spring element 6 on a spring seat of the tool shank 2, which also serves as a tool carrier on. In the tool shank 2, the spring 6 is guided in an inner bore or spring chamber 7 of the tool shank 2.

To the spring chamber 7 is designed as a cap plastic part 8 is arranged. It contains by a specific color scheme recognizable for the user type coding of the tool 1 and deforms from a certain temperature, wherein it penetrates into the spring chamber 7. As a result, a possible thermal sterilization is not only made visually visible, but the melting of the plastic blocks the spring element 6 in the spring chamber 7 and makes the tool 1 useless. During the machining process, bone material is removed. In addition to the bone chips are also tissue parts and blood. These contaminants should be removed from the bore during the working process, otherwise smearing will occur. For this purpose, cooling or rinsing liquid is supplied through an inlet opening in the tool shaft 2. Through the interior of the tool shaft 2, a cooling water channel 3, which continues in the distal end of the guide member 5 and then opens via a transverse bore 9 in two opposite Flächenanschliffe on the pin-like guide member 5, extending from the transverse bore 9 to the proximal end of the guide member 5 extend. Through this channel 3 cooling or rinsing liquid is introduced during the machining process, for example, an isotonic saline solution. The aqueous solution serves, on the one hand, to cool the processing tool; on the other hand, the worn bone parts are flushed out of the hole in the bone. The liquid exits during the machining process at the proximal end of the processing part 4. This ensures that the liquid emerges at the point at which the proximal cutting edge 10 of the machining tool 4 is most active.

The liquid then runs laterally outward in the radial direction from the exit point and along the surface contours of the guide element 5 in the proximal direction to the tip of the guide element 5. The surface contours, corresponding flushing grooves or the like on the guide element 5 can extend as far as the proximal end of the guide element 5 extend to also cool or rinse the guide member 5 and the pilot hole. Although it is difficult for the liquid to flow into the pilot bore in the bone and escape from it, since the guide element 5 is usually seated in the pilot bore only with little play. However, it has been found that the cooling or purging of the pilot is sufficient because it is more important to cool and rinse the cutting-active proximal end of the machining part 4 as the schneidinaktive guide member 5 in the pilot hole. When passing through an aqueous solution, however, pressure does not build up which, in the worst case, could lead to the tool 1 being pushed out of the bore or pilot bore or which may cause the cooling channel 3 in the tool 1 to no longer flow through it and this leads to undesirable heating.

In FIGS. 5 and 6, the cutting edge 10 or main cutting edge arranged on the proximal end of the machining part 4, the concave free surface 11, the two ejection channels 14 serving as the chip space 13, which are arranged opposite one another on the lateral surface 12 of the machining part 4, are in the distal direction an opening angle are opened, and the two opposite minor cutting edges 15, which are each arranged on the rake face 16 of a chip space 13 and formed as a grater 17 illustrates.

The drill head 4, which may also be referred to as a drill bit, has no actively cutting central point, but in this area the drill head 4 is guided by the guide element 5 in the pilot hole when the tool 1 is pressed proximally. The guide element 5 is schneidinaktiv and serves both for conducting the cooling liquid and for guiding the drill 1 in the pilot-drilled pilot hole.

A drilling operation with a tool 1 for drilling a borehole into a jawbone for insertion of an implant proceeds as follows. First, a pilot bore is made in the jaw with a drill whose diameter corresponds approximately to the diameter of the guide element 5. The pilot hole is drilled at a pre-determined, defined depth. Thereafter, the hole is made with the tool 1, wherein the wellbore preferably at one time on his desired final diameter is drilled. Before attaching the tool 1 to the pilot hole, the machining part 4 is in the rebound position, with the tip of the guide member protruding proximally a little opposite the active cutting edge. However, this supernatant is sufficient to attach the drill 1 to the pilot hole, without evading the side.

After attaching the guide member 5 to the pilot hole, a feed force is exerted in the distal direction of the tool with the tool holder. By exerting a feed force of the rotating machining part 4 is pressed proximally in the direction of the pilot hole. In this case, the force applied by the spring 6 counterforce must be overcome. The spring 6 compresses during this process together. The proximal main cutting edge 10 of the processing part 4 is then applied to the force exerted by the user feed force or the restoring force of the spring 6 on the bone or just drilled bottom of the wellbore. If this feed force is smaller than the restoring force of the spring element 6, the machining part 4 against the restoring force of the spring element 6 axially relative to the guide member 5 and the guide member 5 axially relative to the machining part 4 to move without the machining part 4 by a axial stop or blocking of the spring 6 given rebound distal end position occupies. In this region of the feed force, the drill head 4 can work in the axial direction back and forth shrinking or axially pulsating gently into the bone.

However, if the feed force exerted by the user is increased, the processing part 4 reaches the distally located, spring-loaded position given by an axial stop or a blockage of the spring 6. In this position, the user can exert a feed force on the drill head 4, which is greater than the restoring force of the spring 6, and the drill head 4 can not oscillate in the axial direction. This may be expedient for a short time to exercise a higher feed force, for example, when attaching the drill 1 to the pilot hole.

The wellbore is then further drilled, preferably with axially oscillating drill head 4, until the proximal tip of the guide element 5 reaches the bottom of the pilot bore. In this position of the guide member 5, a short moment has to wait until the axially oscillating drill head 5 has worked into its proximal rebounded position. In this, the hole then stops by itself, because the proximally projecting tip of the guide member 5 forms a drilling depth stop. The drill 1 can then be pulled out of the well, leaving the drill head 4 in the rebound position, and the well is gently finished with a defined depth. During the entire drilling operation, the drill head 4 is guided in a defined manner axially along the guide element 5 and there is at no time the risk that it will break off laterally.

FIGS. 7 to 13 illustrate the cutting edge 10 or main cutting edge arranged at the proximal end of the machining part 4, the concave free surface 11, the two ejection channels 14 arranged opposite one another on the lateral surface 12 of the machining part 4 and serving as the chip space 13 Opening angle are open, and the two opposite minor cutting edges 15, which are each arranged on the rake face 16 of a chip space 13 and formed as a grater 17. Further, they show a convex view 18, a tip angle (negative) 19, a rake angle 20, a wedge angle (variable) 21, and a clearance angle (variable) 22.

It can also be seen in FIG. 10 that the two open-space segments 23 at the proximal end of the machining part 4 have a chamfer 24 with which they are chamfered against the direction of rotation. The Bevel 24 leads from the free surface 11 to the discharge channel 14 and to the secondary cutting edge 15 of the opposite of the direction of rotation cutting segment. The cutting edges 15 are oriented so that a clean chip is formed, which can be easily transported by the fluid pressure in the distal direction via the discharge channels 14.

Figures 14 to 34 show a third embodiment of a drill according to the invention in various views, sections and details. It corresponds to the embodiment of Figure 2, with the difference that the machining part 4 is partially conical or double conical and has an outside diameter cutting edge 25. The fastening part 26 shown in FIG. 15 is, for example, a split pin or a grub screw and serves for mounting the tool 1.

FIG. 14 shows a perspective view in the spring-loaded position, FIG. 15 shows an exploded view of FIG. 14, FIG. 16 shows a longitudinal section of FIG. 14, FIG. 17 shows a first side view of FIG. 14 in the rebound position, FIG. 18 shows a longitudinal section AA to Figure 17, Figure 19 is a second side view of Figure 14 in the Sprung position, Figure 20 is a third side view of Figure 14 in the Sprung position, Figure 21 is a longitudinal section BB to Figures 19 and 20, Figure 22 is a plan view to Figure 22, Figure 23 is a section CC to Figure 22, Figure 24 is a section DD to Figure 20, Figure 25 is a plan view of Figure 19, Figure 26 is a first side view of the processing part of Figure 14, Figure 27 is a second FIG. 28 is a side view of the processing part of FIG. 14, FIG. 29 is a longitudinal section AA of FIG. 26, and FIG. 30 is a detail B of Figure 26, Figure 31 is a plan view of Figure 26, Figure 32 is a detail of Figure 31, Figure 33 is a section CC to Figure 27 and Figure 34 is a section FF to Figure 27. The processing part 4 has on the outside a diameter cutting edge 25. It is preferably located on a conical proximal portion of the processing part 4, which has a conical slope, ie, tapers from the distal to the proximal end. The opening angle 27 of the cone can advantageously be, for example, between 1 ° and 25 °, preferably between 5 ° and 15 °. In the illustrated embodiment, the opening angle is 10 ° (see Figure 27). The diameter cutting edge 25 has a swirl pitch which extends in the direction of rotation of the machining part 4 to the proximal end of the tool 1. With the diameter cutting edge 25 on the cone, the diameter of a bore drilled with the tool 2 can be increased during drilling or a conical bore can be introduced into a bone. By the slope of the diameter cutting 25 thereby abgespantes material is removed in the distal direction of the wellbore.

The processing part 4 may also be formed two or more conical, ie, have successive conical sections, each having different opening angle. At the junctions between these sections, the opening angles may change continuously or discontinuously, and one or more cylindrical sections may also be provided, arranged between conical sections or at a distal or proximal end. Correspondingly, it is also possible to provide conical sections with a negative opening angle 27. A negative opening angle is referred to as exemption 28. The clearance 28 can facilitate the removal of material abgespantem by the free space is increased to the borehole inner edge. It may advantageously be for example between 0, 1 ° and 5 °, preferably between 0.5 ° and 2.5 °. In the exemplary embodiment shown, a section with an open area adjoins the proximal conical section in the distal direction. Position of 1.5 ° (see Figure 28). In general, it is advantageous if the release is arranged at the distal end of the processing part.

LIST OF REFERENCE NUMBERS

1 surgical tool

2 tool shank

3 channel

4 processing part

5 guide element

6 spring element

7 spring chamber

8 plastic part

9 transverse bore

10 (main) cutting edge

11 concave open space

12 lateral surface

13 chip space

14 ejection channel

15 secondary cutting edge

16 rake surface

17 grater

18 convex view

19 point angles

20 rake angle

21 wedge angle

22 clearance angle

23 open space segment

24 bevel

25 diameter cutting edge

26 fixing part opening angle

exemption

axis of rotation

Claims

claims

Surgical tool (1) for working on bones, in particular for drilling bones for the insertion of a dental implant

a tool shank (2) which is designed to be clamped in a rotatable tool holder and has a channel (3) for passing a cooling or rinsing liquid,

a machining part (4) which is rotatable about an axial rotational axis (C) and which is drivable by the tool shaft (2) and arranged at the proximal axial end of the tool shaft (2), and a guide element (3) extending in the axial direction of the tool (1). 5) disposed at the proximal axial end of the processing part (4) and adapted for insertion into a pilot bore,

characterized in that

the machining part (4) is axially movable relative to the guide element (5) and

the tool (1) has a spring element (6) which generates a restoring force which moves the machining part (4) in the proximal direction, the machining part (4) being movable axially against a rebounding force between a rebounded and a rebounded position.

Surgical tool (1) according to one of the preceding claims, characterized in that the machining part (4) has at least one cutting edge (10) at its proximal end.

3. Surgical tool (1) according to the preceding claim, characterized in that the proximal cutting edge (10) of the machining part (4) has a concave free surface (11).

4. Surgical tool (1) according to one of the preceding claims, characterized in that the machining part (4) has at least one chip space (13) serving as ejection channel (14) which is arranged on the lateral surface (12) of the processing part (4) and extends substantially axially.

5. Surgical tool (1) according to the preceding claim, characterized in that the discharge channel (14) is open in the distal direction by an opening angle.

6. Surgical tool (1) according to one of the preceding claims, characterized in that the machining part (4) has at least one secondary cutting edge (15) with very little or no swirl pitch, preferably on the rake face (16) of the chip space (13).

7. surgical tool (1) according to the preceding claim, characterized in that the at least one secondary cutting edge (15) is designed as a grater (17).

8. Surgical tool (1) according to claim 1, characterized in that the guide element (5) has on its surface at least one axial Spülungsnut, axial flattening, axial bevel, an axial incision or an axial surface grinding, by means of the cooling or rinsing liquid towards the proximal end of the processing part (4) and / or to the proximal end

End of the guide element (5) is conductive.

9. surgical tool (1) according to the preceding claim, characterized in that the tool (1) and the Spülungsnut or flattening, axial chamfer, the axial incision or axial surface grinding are formed such that the exit point at which the cooling or rinsing liquid from the channel (3) exits into the flushing grooves, in the region of the transition between the proximal axial end of the machining part (4) and the guide element (5) is arranged.

10. A surgical tool (1) according to any one of the preceding claims, characterized in that the guide element (5) protrudes in the rebounded position of the machining part (4) at the proximal end of the machining part (4).

11. A surgical tool (1) according to any one of the preceding claims, characterized in that it comprises a plastic part (8) which consists of a plastic which deforms at a temperature which is below the sterilization temperature of the tool.

12. Surgical tool (1) according to the preceding claim, characterized in that the plastic part (8) is a cap which is arranged above or around a spring element (6) containing the spring chamber (7), that it deforms in the Spring chamber (7) penetrates.

13. Surgical tool (1) according to one of the preceding claims, characterized in that the machining part (4) has one or more conical sections.

14. Surgical tool (1) according to the preceding claim, characterized in that the machining part (4) has a diameter cutting edge (25).

15. Surgical tool (1) according to the preceding claim, characterized in that the diameter cutting edge (25) is formed in a conical portion of the machining part (4).