GB2483089A

GB2483089A - Trephine drill with transverse saws to remove a cylinder of bone

Info

Publication number: GB2483089A
Application number: GB1014234.7A
Authority: GB
Inventors: Benjamino Kah Hung Lee
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-08-25
Filing date: 2010-08-25
Publication date: 2012-02-29
Also published as: GB201014234D0

Abstract

A device for removing cylinders of bone has at least one spring biased transverse saw blade that cuts through the base of the cylinder. The device may be an integral saw and drill bit (figures 1 3) or it may be a transverse saw (diagrams A D) used following a standard trephine drill bit. In a preferred embodiment, the device is a drill bit having an annular body 15 towards the bottom of which are pivotally mounted two saw blades 1 in the plane perpendicular to the longitudinal axis of the bit. The blades are spring biased to pivot towards the bit axis but are restrained by locking pins 13 attached to an external ring platform 7. In use, when the ring platform contacts bone it moves relative to the bit body, raising the pins and releasing the saw blades to cut through the base of the bone plug.

Description

A Modified Trephine Bone Drill.

This invention relates a modified trephine bone drill, for use in implant dentistry, suitable for and capable of harvesting and delivering a precise, pre-determined sized,autogenous whole block of bone from the patient's own jawbone, piecemeal, intact and in one single action,from the top of the patient's gums.

An ordinary trephine bone drill is a hollowed out drill commonly used to drill bone around existing dental implants which have failed and the subsequent removal of the failed implant is aided by the use of dental extraction forceps.

Whereas an ordinary trephine bone drill can create a cylindrical stump of bone as it drills,it cannot severe the end of the stump in order to free it,and also to retrieve it.This modified trephine bone drill aims to go one step further,in addition to normal trephine drilling,to achieve this final objective.

Over the past decade, the use of dental implants to replace missing teeth has become widespread and increasingly popular over conventional dental bridges and dentures.A dental implant does not require drilling adjacent teeth for their support and are wholly independent,highly successful,durable and are said to have 95% or more predictable successful results,given that there is adequate bone to support them.In many cases the dental implant has become the only final solution for the patient.

The bone factor: The most worrying factor during a dental implant placement is the amount of available bone to surround and to support it,and to achieve initial stability for the osseointegration to become successful, i.e. for the bone to fuse to the titanium implant surface which can take from 3 weeks to 3 months,or sometimes longer.

In many or most cases,the j awbones have been severely destroyed by gum disease and the minimum available bone height to house the implant is often inadequate, 6mm to 8mm being the absolute minimum required.Without bone grafting procedures, especially in older patients,many dental implant placements are not possible.

Where and how to get the extra bone? 1.Bio-Oss bovine bone,i.e.cow's bone (plus the use of membranes to barrier them from the gums) has become very popular, and highly successful. It comes in powdered form and it is mixed with saline to patch the defect, or packed into the sinus floor to create bone to house a dental implant.However, there are 2 problems with use of animal bone, albeit, a high quality product.Firstly Bio-Oss bovine bone takes up to 9 months to strengthen enough to hold a dental implant, yet it has a dull and dead feel and the quality does not compare to the patient's natural vibrant and resilient bone. Secondly, there are concerns from the patients' point of view that it is of animal bone, and the scope of acquiring mad cow disease, though unlikely, remains to be a worrying factor that one cannot completely rule out; and allergy, being another.

2.Autogenous bone, i.e. the patient's own bone, is the ideal and choicest bone to use for bone augmentation in implant dentistry,whenever needed. Autogenous bone is the "Gold Standard" and is the absolute,natural ideal if one can obtain it from the patient's own body. This is where the difficulty lies.The complexity and risks of such procedures render most dental operators unable to proceed at this point. Specialist oral surgeons are capable of harvesting autogenous bone from chosen donor sites in the patient's mouth, but nevertheless it is no easy task.It is tedious, risky and often destructive.

Minimal invasive techniques for atraumatic surgery in the quest to obtain autogenous bone is the ideal,but is difficult to achieve in oral surgery practice today,using conventional methods.

The significance of this invention.

A new approach to this problem stems from the realization that,in many or most cases,there are also other missing teeth where there is good quality and quantity of bone and are all suitable for harvesting,for example,missing premolars, absent/missing wisdom teeth,missing molars in the opposite jaw,or other side of the mouth, and these are all good candidate donor sites for bone harvesting with the use of a suitable device,and the modified trephine bone drill is fit for this purpose.(The bone of these gaps are otherwise typically wasted and washed away by ordinary procedures with bone drills during their conventional replacements with dental implants).

A new,bereby proposed, method to harvest bone is to look for those diseased teeth,and wisdom teeth which are already planned for extractions.In such case, all of these teeth are first extracted, and the patient returns in 3 months time when new bone had regenerated and filled these sockets to the brim.The modified trephine bone drill is now applied to harvest this new bone,collectively,and the new sockets created are immediately ready to receive the exact matching sized dental implants,specifically made for this modified trephine bone drill;or any ordinary dental implant of nearest size. This collection of harvested bone blocks (as precious as gold nuggets) are ready for fitting into the deficient sites of the jaws where dental implants are also to be placed.

Alternatively,on the other hand,this volume collection of bone blocks remain inadequate to replenish the severely deficient sites of the jaws (e.g.for the severely atrophic posterior mandible or maxilla), then thsee sockets are simply allowed to heal again for a further 3 months for a second round of bone collection,and these are further added to the deficient sites of the jaws;and the whole process can be repeated yet again after another further 3 months interval,and so on,again and again,until fmally all the deficient bone areas of the jaws have been completely replenished and suitable to house dental implants (i.e.areas where it was previously thought to be impossible for placing dental implants).

Finally all the sockets repeated used for bone harvesting have dental implants placed into them.

The unique and distinguishing feature of this invention, is that it removes bone blocks in such an exact fashion that the voided sockets it creates in the process,will completely heal,henceforth allowing the continual repeatable harvesting of the invaluable bone blocks every 3 months interval,as required This process is made possible by the fact that the cortical plates of the jaws are not breached during the harvesting procedure using this invention, (as shown in diagrams l-4).As new bone will certainly regenerate between intact cortical bone plates,this provides an unlimited supply of autogenous bone for bone grafting procedures in the niost conservative way.

3.There are other lesser choice forms of bone,Allografts,i.e.bone from cadavers,(the worrying factor being AIDS),Alloplasts,or synthetic forms like ceramic grafts,or Hydroxyapatite and tricalcium phosphate,Bioglass,etc. and so on, but they are mostly in powdered form and cannot provide the solid block of "bone" for piecemeal usage.In addition,these are expensive materials and require expertise.

The modified trephine bone drill.

The idea of this drill is to remove a precise block of the patient's bone conservatively from within the jaw,approaching from through one tiny hole at the top of the gums.It can be used by any operator who is experienced in implant dentistry.

Once a block of bone can be obtained,as like harvesting a gold nugget, then the possibilities are endless.It is most desirable and the scope of usage is beyond the scope of this manuscript.It can also be crushed into fragments,by a special bone crusher,and the fragments can be used as filler particles in defect sites.

The tools available today for the Specialist Oral Surgeon to harvest bone are mostly crude and generally imprecise,relying entirely on the skill of the operator's hand.Chunks of bone are sawed out with external rotary saws and often the donor sites are left "amputated".Conventionally bone is removed with an external approach from the outside of the j awbone,bre aching the outer plate of the jaw,i.e.the cortical plate.

Additionally, some bone can be wasted in the crude process.For very severe cases, this is unavoidable, but for many or most moderate cases encountered by the implant dentist,this modified trephine bone drill can become an invaluable tool and will prove to be sufficient.

The modified trephme bone drill aims to remove only the predetermined cylindrical block of bone within the drill, piecemeal,and within the cortical plates of the jawbone. The advantage of this procedure, apart from it's safety and simplicity,is that it allows the cortical plate on either side of the empty socket created to be completely preserved,unlike the current methods. The socket will completely fill up with new bone in 3 months.Alternatively, a suitable sized dental implant can conveniently and immediately be placed right into this very socket.To fulfill this alternative choice,it is hence possible and suggestible that matching sized dental implants be made available,and specifically for gently press-fitting exactly into the very socket created by this modified trephine drill.

Design features.

1.End-cutting,spring loaded,transverse saws,activated only at exactly the predetermined depth,or prematurely activated by the experienced operator's finger tip.

2.Saws are readily reloadable for multiple usages.

3.Conservative and precise.

The advantages: l.Quick and easy to do for any Implant Dentist,and a useful tool for the Specialist Oral Surgeon.

2.No additional risks mvolved, and it harvests bone most conservatively,rnethodically and precisely.

3.The bone donor site is usually available wherever else teeth are missing,including the wisdom teeth.

4.The end-cutting saws "seal the deal" to create an intact block of bone which is then delivered out of the mouth.

5.Sterilizable,durable and a precision instrument which reduces trauma to the patient in lieu of external incisions and external bone drillings.

6.Simplifies implant dentistry and once with blocks of bone easily removed(like bricks for a wall),this instrument opens many new ingenious possibilities and introduces new surgical techniques for implant dentistry.

7.Preserves both of the (buccal and lingual) cortical plates of the jawbone.

Apart from dental implant uses,tbis invention is also capable of industrial uses if modified up in scale for the drilling of wood;as in carpentry, or of all other solid materials during manufacturing.

Due to the precise nature of this device,it offers the benefit of reducing wastage of materials, if for example, multiple cylindrical shaped items are needed to be cut from a large block of raw material.

Other potential uses of this invention may include medical uses as in orthopedic surgery,perhaps for the purposes of obtaining a bone biopsy of any part of the human skeleton, as required.

Description:

Embodiments of the present invention will now be described with reference to the following drawings, in which: Fig. 1 is a side view showing the basic components of the invention.

Fig. 2 is a side view of the invention illustrating that the drill shaft is separable and/or connectable to the trephine drill body via a screw thread connection.

Fig. 3 is a cross-section view along the line A-A in Diagram 2 Diagrams. 1-4 illustrates the process of bone harvesting with the use of the present invention.

With reference to Fig 1,the individual components are now described with the following, and numbered as according to those labeled 1.Transverse cutting saws.

There are 2 flat semi-circular saws,with their serrated sharp teeth facing each other,and towards the centre of the trephine drill.They aim to cut in the horizontal plane along the line A-A as shown on fig.2.However there can be 3 or more saws in future designs, all with the same purpose of sawing across the base of the bone block simultaneously. The saws are hinged at one end, and are spring loaded, providing potential energy to push them towards each other in the transverse plane, towards the longitudinal central axis of the trephine drill,and meet at a point along the line B-B as shown on fig.2.

2.Hinge.

One end of the saw rotates along this hinge.

3.Hole or deep depression notch, or groove, in the body of the saw to receive end of the locking pin.

This locks the saw into its inactive, resting position, held within the boundary of the trephine drill body and out of the trephine drill cavity.

4.Spring for transverse cutting saws. This spring pushes the saws towards the centre of the trephine drill cavity.

5.External ring with flat surfaces, suitable to receive a spanner.This external ring is rotatable manually from the outside and can be hexagonal or octagonal,so long as a spanner is able to engage and rotate it.It is connected internally to one end of the saws,with a fixed-length wire,and its rotation with an external spanner can control it to move the saws back into its resting,locked position,as shown in Fig. 3A.

Dimension of this ring does not exceed the overall external diameter of the trephine drill and rotates freely (when not engaged by a spanner)around a given internal transverse groove.

6.Wire to connect external ring (5) to the tip of the transverse cutting saw.

7.Extemal ring platform incorporating 2 long vertical locking pins,in one casting.This is an important feature module of the invention.The 2 vertical locking pins fit within 2 vertical tunnels within the trephine drill body and are spring-loaded within,to potential energy to push,at all times,towards a hole(or deep groove in the body of the saws)in order to lock them.There can be 3 or more locking pins in future designs,but only one external ring platform.The external ring platform,once lifted when it comes into contact with the crest of the bone as shown in Fig.2,or alternatively purposely lifted by the fmger tip of the operator,at any point during the drilling procedure,the tips of the locking pins disengage from the holes(or deep groove of the transverse cutting saws),and the spring-loaded saws are activated to "spring into action".

8.Internal spring coil,within the vertical tunnels provided for the vertical locking pins,exert energy to compress the locking pins downwards and towards the saws.

9. Stopper, near the end of locking pin.

1O.Intemal stopper within the tunnel.

11. Stopper ring to limit the upper movement of the external ring platform (7).

12.Threaded screw connection,of the drill shaft.

This important feature separates the drill body from the drill shaft so that any other forms of drill shaft correlating to different handpieces can be used,as preferred by different operators.In addition this opening created by the threading separation,allows the harvested bone to be delivered from this top end opening.

13.Vertical locking pin.

14.Vertical tunnel to house the locking pin.(Rather like a root canal).

15.Body of the trephine drill.

16.Drill shaft lid,is fixed connected to the drill shaft 17.

1 7.Drill Shaft,is fixed connected to the drill shaft lid 16.

1 8.Trephine drill cavity,a cylindrical empty space to receive and house the anticipated harvested bone.

19.Bladed and serrated outer surface of the trephine drill body to cut bone(as any trephine drill).

20.Bladed and serrated edge of the trephine drill body to cut bone(as any trephine drill).

21.Bladed and serrated inner surface of the trephine drill body to cut bone(as any trephine drill).

With reference to Diagram 2, this illustrates the screw thread connection (and/or separation) of the trephine drill body from the drill shaft module,the latter capably being of all different variations of shapes and sizes to fit different handpieces.

With reference to Diagram 3A,this illustrates in cross-section view along the line A-A of Diagram 2 the position of the saws in their resting positions and locked by the ends of the locking pins.

With reference to Diagram 3B,this illustrates in cross-section view along the line A-A of Diagram 2 the position of the saws in their active positions when disengaged by the ends of the locking pins.

The drilling procedure is now described in the following a-j.

a.A tiny line incision (i.e. a cut) is made on the top of the gum;right at the top of the ridge of a donor site (typically with use of a No.15 surgical blade) to expose the underlying top ridge,or crest of the bare bone.

b.The modified trephine drill is used to drill vertically into the bone until the external ring platform(7) at the top of the drill,contacts the top ridge of the bone.A further 1mm insertion of the drill lifts the external ring platform(7) and its 2 pins whose tips locked the spring-loaded transverse saws,previously piercing the holes in the midst of these saws,and now immediately releases them. The saws now spring into action.

c.With the spring-loaded transverse saws now with their teeth exerting a heavy constant and continual transverse force against the cylindrical block of bone,towards it's central axis,continual rotation of the drill,without any further downward force exerted by the operator's hand,the base end of this cylindrical block of bone is being sawed off methodically.

During the rotation of the trephine drill,the saws being hinged to the inner surface wall of the drill are effectively dragged into rotation to horizontally cut the base of the bone stump created by the trephine drill.The 2 saws cut opposite and towards each other in harmony.The tips of the saws are connected via a limited length of wire(6) and connected to the external ring(5),whicb limits the saws when their cutting edges meet at the centre of the cavity( 18).

d.Once the distant end of the cylindrical block of bone is completely sawed,the operator can feel the sudden drop in resistance as the drill rotates more freely.

e.As the hinged and spring-loaded transverse saws have now invaded the cavity(18) and are right underneath the block of bone created,they support the block of bone and form a floor,sealing the bone block completely within the trephine drill.The drilling stops.

f. The entire trephine drill is removed from the jaw and out of the mouth,and onto a sterile surface.

g.The gum can now be closed with 1 stitch,to cover the socket created.(Alternatively a suitable dental implant is inserted gently into this socket,and no stitching is required).

h.Tbe external ring (5) is rotated anti-clockwise,with use of a suitable spanner tool,and the wires (6) pull the saws back into their resting positions,out of the cavity(18), and locked into place by the 2 spring-loaded pins(13).The block of cylindrical bone falls out of the cavity(18) and onto the operator's hand.

i.Alternatively,the drill shaft(17) at the top of the trephine drill,can be unscrewed off the trephine drill at the screw connection threadings(1 2),and the harvested block of bone is delivered (or drops out) from the top of the trephine drill.

j.The drill shaft(17) and the drill shaft lid(16)can be made available in 2 different formats,short latch-grip for use with a contra-angle handpiece,or long friction-grip for use with a straight-handpiece,depending on the operator's personal preference.Either forms can be screwed onto the trephine drill body at the threading( 12).

Further points: The length of the cylindrical bone block is limited by the external ring platform(7),wbich in turn is limited by a stopper ring(1 1) at its upper end,and limited at the lower end by top of the transverse saws.The diameter of the bone block is determined by the internal diameter of the inner cutting surface(21)of the trephine drill.

The 2 transverSe saws are hinged at their bases,connected to the inner surface of the trephine drill,and allowed to move only in 2 dimensions,i.e.transversely across towards the central axis of the cavity(118).

Emergency feature: In the emergency event that,for any obscure reason that the saws have broken and are jammed during their cutting action,the drill shaft (17) and drill lid (16)can be unscrewed at the connection threading (12)and the bone block is drilled out conventionally with an ordinary bone drill, and optionally the bone fragments can be collected in a special filter designed within a surgical suction tip.The trephine drill is then freed and removed from the mouth.

With reference to Diagrams 1 -.4, an example is now given to illustrate the functioning use of the invention: Diagram 1.

The modified trephine drill is pushed down as it drills it's way into bone,as any normal trephine drill.

Diagram 2.

Once it reaches a desired depth,the external ring platform contacts the top ridge of the bone and is lifted up as the rest of the trephine drill descends further.The 2 pins are equally lifted and disengage from the holes within the saws.

Immediately the spring-loaded saws are released and activate force on the base of the bone stump,now within the trephine drill,cutting transversely towards each other,whilst the drill remains in rotation.

When the 2 saws finally meet at the centre,the bone stump is completely severed and entirely housed within the drill.

Diagram 3.

Drillling stops and the trephine drill is delicately removed from the mouth.

Diagram 4.

A separate spanner engages on the external ring near the end of the trephine drill, it rotates it clockwise and the saws are forced back into within the trephine drill body,compressing their springs and the pins snap back into the holes to lock them in.Immediately the block of bone falls out readily onto any sterile metal plate.

An Alternative Design:The End-Cutting Trephine Drill.

A variation of the modified trephine drill is possible and this version of the design precludes the serrated surfaces of the normal trephine drill,i.e. it omits items labelled 19,20 and 21 as shown on Diagram 1. This variation of the design is now shown on Diagram V and focuses entirely on the transverse sawing of the bottom end of the bone block created by the trephine drill and intends solely to control the saws for the purpose of their sawing.

This alternative device is intended to be used in partnership with the ordinary trephme bone drill.

The bone block is first created by use of a normal trephine bone drill,in the normal fashion,drilling the bone down to any chosen depth intended by the operator.Once this is achieved,the trephine drill is removed from the mouth.

The End-Cutting Drill is next introduced into the bone to that fmal cutting position left-off by the normal trephine drill;where it continues to saw the bottom end of the block of bone for the harvest.

Embodiments of the End-Cutting Trephine Drill will now be described with reference to the drawing of Diagram A, showing a side view of the module.

101 External ring with internal serrated mechanical teeth.This embodiment is a most important feature because it indirectly controls the position of the saws.

It is rotatable when lifted and locked into either; position A, or position B, via an internal triangular protrusion, in the casting, which fits either into the triangular slot of position A or position B, at different times,of the trephine body.The internal surface of this large external ring has serrated mechanical teeth to engage with both the external serrated mechanical teeth of the two internal wheels 102;rather like the mechanical gearbox mechanisms,rotating, andlor locking them henceafter,simultaneously.

102 Internal wheel with external serrated mechanical teeth; are fixed to the top end of the rectangular rods.

103 Rectangular rod; is a long vertical rod which pass down within the trephine body (within a given tunnel),and the bottom end of the rod is fixed connected to one end of the transverse cutting saw.

104 Transverse cutting saws.

Drill shaft; is again thread-screw connectable to/separateable from the trephine drill body.

106.Screw Thread connection of the drill shaft to the rest of the trephine drill body.

In function: Initially when the External Ring is in position A, the transverse cutting saws are at their rest positions and seat within the boundaries of the trephine body, and hence,does not block entry of the bone stump into the cavity of the trephine drill, as the drill is first drilling down into the bone.

As shown on diagram B,once the trephine drill is in position,the External Ring 101 is lifted,rotated anti-clockwise,and firmly seated into position B.At this moment in time,both of the internal wheels 102 are equally rotated and the rectangular rods in turn rotate the transverse cutting saws.

Due to, now, the presence of the bone block within the trephine drill itself,as shown on diagram C,the saws are held back with this contact,and the external ring is locked in position B and disallowed to move back to position A,the saws are pressed against the bone.This creates a heavy tension within the rectangular rods,in effect twisting them. This potential energy created is transferred to the saws which forces themselves towards each other, and so,whilst the drill is rotating,they saw into the bone.

(ie.continual rotations of the drill in clockwise fashion will effectively saw the base of the bone block,and completely, in the midst of this heavy tension created).

A yet further alternative design of the trephine drill is shown in Diagram D. This design is similar to the previous design of the end-cutting trephine drill shown in Diagram A except for the following differences: i. There is a Horizontal Bar Spring (S),as shown on Diagram D which is firmly attached at one end to the drill shaft, and passes underneath the external ring, (101)and its other end lies passively at the triangular notch of position B. ii. The drill shaft is firmly attached to the trephine drill body with no screw-thread connection between them. In other words the drill shaft and the trephine drill body are in unity as one single module.

iii. The rectangular rods (103) are not flexible nor twistable, and are completely rigid,with limited twisting whilst in tension.

In this design, before the trephine drill is introduced into the bone,the operator first lifts the external ring (101) and rotates it clockwise, effectively moving it's triangular notch from position B to position A,where it seats the external ring.During this rotation,the Horizontal Spring (S) is bent backwards and held in this position by the external ring,now locked in position A.This creates a potential energy in the horizontal spring as it exerts a force with a bias towards moving back to position B,its passive state.

At the instant the trephine drill is in-position for the transverse cutting saws to cut the bone, the operator uses his finger tip to lift the external ring out of the position A,and begins drilling. This lifting of the external ring disengages the triangular protrusion underneath which was seated in the notch,and the horizontal spring whilst dc-rotating (anti-clockwise)the external ring back towards position B,via the rectangular rods,are in effect,rotating the transverse cutting saws towards the centre of the trephine drill.

As the drill is rotating,and during the external ring is in transition of de-rotating,(effected by the horizontal spring from position A to position B,via both the internal wheels (102) and the rectangular rods (103)), the transverse saws are cutting into the base of the bone block and moving towards each other,until they meet at the centre of the trephine drill.At this point the base of the bone block is completely severed and the external ring has reached position B;(where its triangular protrusion neatly snaps into the triangular slot,a further hidden spring beneath the external ring may be provided for this purpose).

The trephme drill is removed from the mouth,and the external ring is once again lifted and rotated to the position A,where via the rectangular rod connection,the transverse cutting saws are rotated out of the trephine drill cavity and tucked-in within the trephine drill body,and the harvested block of bone is freed,and readily dropped down and out of the trephine drill.

It can be seen that such a modified trephine bone drill offers the following advantages over prior art: a.Only a single incision equal to the width of a tooth at the top of the gums is required to obtain a block of bone with the use of this drill.

b.There is no absolute necessity for suturing the gums after the operation;and only optionally so with one tiny suture.

c.This drill removes bone in such a way that it leaves the void (socket) it created,completely capable of full bone regeneration by 3 months post-operative,leaving no disfigurement to the jaws.

d.This drill offers the ability to re-harvest the same bone repeatedly,and without any disfigurement to the jaws,offering an unlimited supply of autogenous bone for the dental surgeon.

e.This drill offers more simplicity and precision over prior art, for the purpose of harvesting bone.

f.This drill manufactures building blocks of autogenous bone,in identical cylindrical shapes,from one site of the jaws for anotheras like manufacturing bricks for a wall.

It should be understood that the above only illustrates examples whereby the present invention may be carried out,and that various modifications and/or alterations may be made thereto without departing from the spirit of invention.

It should also be understood that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may be provided in combination in a single embodiment.

Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any appropriate sub-combinations.

Claims

CLAIMS.1. A trephine drill including: -Separateable drill shaft module and trephine drill body.-Stopper ring.-External ring platform incorporating 2 locking pins.-Transverse cutting saws.-External ring with flat surfaces.
2. A trephine drill according to Claim 1 wherein the drill shaft module is connected to the trephine drill body via a screw thread.
3. A trephine drill according to Claim 1 wherein the external ring platform incorporates 2 or more locking pins.
4. A trephine drill according to Claim 1 wherein the locking pins are spring-loaded.
5. A trephine drill according to Claim 1 wherein the transverse cutting saws are spring-loaded.
6. A trephine drill according to Claim 1 wherein there may be 1,2 or more transverse cutting saws.
7. A trephine drill according to Claim 1 wherein the transverse cutting saws are engageable by the locking pins.
8. A trephine drill according to Claim 1 wherein the transverse cutting saws are moveable towards each other in the same plane.
9. A trephine drill according to Claim 1 wherein the transverse cutting saws are hinged.
10. A trephine drill according to Claim I wherein the 2 or more locking pins are freely moveable within the trephine drill body.
11. A trephine drill according to Claim 1 wherein the external ring with flat edges is rotatable and is connected by a wire to the transverse cutting saws.
12. A trephine drill according to Claim 11 wherein the external ring with flat surfaces capably controls the movement of all transverse cutting saws simultaneously.
13. A trephine drill according to Claim 1 wherein the movement of the locking pins are at right angles to the movement of the transverse cutting saws.
14. A trephine drill according to Claim 1 wherein the spring-loaded pins are biased towards compression on the transverse cutting saws.
15. A trephine drill according to Claim I wherein the spring-loaded transverse cutting saws are biased towards compression of the transverse cutting saws towards each other.
16. A trephine drill according to Claim 11 wherein the the wire,connected to the external ring with flat edges,limits the movement of the transverse cutting saws at the point when the saws come into contact.
17. A trephine drill according to Claim 1 wherein a stopper ring limits the upper movement of the external ring platform incorporating locking pins,module.
18. A trephine drill according to Claim 1 wherein the external ring platform is firmly connected to the spring-loaded locking pins.
19. An end-cutting trephine drill including: -An External ring with internal serrated mechanical teeth.-Internal wheel with external serrated mechanical teeth.-Rectangular rod.

-Transverse cutting saws.

-Drill shaft,
20. An end-cutting trephine drill as according to claim 19 wherein a large external ring embraces the top of the trephine drill,engages both of the internal wheels via mechanical teeth within it,and is rotatable when lifted and lockable in separate positions A and B when seated,via an internal triangular protrusion into the corresponding triangular notches of positions A and B.
21. An end-cutting trephine drill as according to claim 19 wherein the internal wheels are fixed connected to one (top) end of the (vertical) rectangular rods.
22. An end-cutting trephine drill as according to claim 19 wherein the rectangular rod exist within a tunnel running down the body of the trephine drill,and the distant (bottom) end of this rod is fixed connected to one end of transverse cutting saw.
23. An end-cutting trephine drill as according to claim 19 wherein the rectangular rod is of a flexible and twistable metallic property capable to store potential energy.
24. An end-cutting trephine drill as according to claim 19 wherein the transverse cutting saws pivot and swivel,in the transverse plane, around its base-end line connection to the rectangular rod.
25. An end-cutting trephine drill as according to claim 19 wherein the drill shaft is connectable and/or separateable from the trephine drill body.
26. An end-cutting trephine drill as according to claim 19 wherein the trephine drill body itself,in this design, has no serrated cutting edges,and is otherwise a smooth surface drill,except for the transverse cutting saws.This feature ensures the operator that no further cutting is induced by this drill,except for the transverse cutting saws,
27. An end-cutting trephine drill as according to claim 19 wherein this design reserves the right to retain all of the serrated and cutting surfaces of the trephine drill,to be included.
28. An end-cutting trephine drill as according to claim 19 wherein there can be two,three or more rectangular rods,internal wheels and transverse cutting saws.
29.A trephine drill according to Claim 1 wherein this trephine drill is capable to cut into a solid material in two plane dimensions in sequence; initially in the vertical dimension,and thereafter, whilst the trephine drill remains and held stationary,also and only then allowable,to cut additionally in the horizontal direction.