WO2005089669A1

WO2005089669A1 - Dental implant

Info

Publication number: WO2005089669A1
Application number: PCT/EP2005/051106
Authority: WO
Inventors: Eilert Eilertsen
Original assignee: Eilert Eilertsen
Priority date: 2004-03-12
Filing date: 2005-03-11
Publication date: 2005-09-29
Also published as: GB0405655D0

Abstract

A dental implant for securing a crown is provided. The implant comprises an implant portion for interfacing with a jaw bone of a patient and an integral abutment 5 portion tapering from the implant portion to form a distal portion that is arranged to interface with a crown.

Description

DENTAL IMPLANT

The present invention relates to dental implants and, in particular, to dental implants that form a replacement for a tooth.

It has been known in the art for some time that a replacement tooth may be provided. This is typically done by providing a implant which is secured into the jaw bone of the patient. Subsequently an abutment portion provides an interface between the implant and a crown.. The abutment portion is fabricated during surgery within the mouth of the patient in order to provide an abutment specifically tailored to the gap in the mouth and taking into consideration the size and angle to the tooth to be replaced. A crown is subsequently attached to the implant. This is generally performed during second stage surgery and, in the interim, it is known to use a temporary crown to protect the abutment portion from damage and also from causing damage to the patient's mouth between the stages of surgery.

In order to reduce the lengthy first stage surgery required to fabricate the abutment portion within the mouth ofthe patient, recent developments have been made that allows the provision of a selection of abutment portions of various sizes that may be supplied pre-formed for insertion during first stage surgery. Although this reduces the variety of sizes of abutments and, also, the angle at which the abutment may lie, this has not been deemed, in practice, to be a serious disadvantage as the majority of situations may be dealt with using one of a range of pre-formed abutments of various sizes.

A schematic view of the current state of the art is shown in Figure 1. The assembly consists of three parts: a cone shaped implant portion 3, an abutment portion 5 and crown 7. The crown may be ceramic, gold or platinum. The implant portion 3 screws into the jaw bone of the patient, the abutment portion 5 interfaces with the implant portion 3 and extends through the gum of the patient to protrude into the mouth. The abutment portion 5 has a tapered portion 4 that interfaces with the implant portion 3. Above the tapered portion is a shoulder 6 that extends through the gum of the patient and provides a lip 8 that lies at the gum margin and with which a crown 7 interfaces, in use. The interface between the crown 7 and abutment portion 5 occurs at the upper extreme of the gum of the patent. A problem with this system is that it is possible for bacteria to enter the tooth assembly at the interface between the lip 8 of the abutment 5 and the crown 7 as this interface occurs at the gum margin and may therefore be exposed if the gum recedes by even a small amount. Bacteria in this region may lead to an infection which may, in turn, cause the bone to recede requiring the replacement of the implant and tooth in due course. Furthermore, it is possible for plaque to build up on the abutment portion 5 which is generally made from titanium.

The present invention aims to overcome the problems associated with the prior art by providing a sleeve portion that obviates the need for an interface at the gum margin and allows the material of the crown to extend to the bone line. This aim is achieved by the provision of a sleeve portion that interfaces with an a abutment portion and extends from the bone line into the crown. Furthermore, in order to maintain a three piece system the abutment and implant portions have been combined to form a single piece. According to the present invention there is therefore provided a dental implant for securing a crown, the implant comprising: an implant portion for interfacing with a jaw bone of a patient, an integral abutment portion tapering from the implant portion to form a distal portion that is arranged to interface with a crown.

In recent years the dental profession has become accustomed to working from a discrete set of abutment portions and it will therefore cause no further limitation to have a range of combined abutment and implant portions. This will reduce the number of pieces required for the tooth implant as a whole and will reduce the time required in surgery.

The abutment portion is preferably formed in one of a plurality of different lengths and angles relative to the implant portion. This variety in length and angle allows a suitable implant to be selected for the patient.

Preferably, the abutment portion tapers and is provided with a milled chamfer which, in use is aligned with the upper surface of the patient's jaw bone. This results in good retention of the implant and reduced the possibility of bacterial and plaque build-up. Furthermore, according to the present invention, there is provided a dental implant system comprising a dental implant as described above and, furthermore, a sleeve for engaging with the abutment portion of the implant and a distal portion on which a crown is formed. The sleeve removes the interface at the gum margin that is common in known systems. The sleeve is made from the same material as the crown and enables that material to extend down to the jaw bone of the patient solving the problem of bacteria and plaque build-up at the gum margin as a result ofthe interface between the abutment portion and crown being arranged to lie at the gum margin. During the initial stage of surgery, an acrylic sleeve portion may be used and a temporary crown applied. During a second stage of surgery, a ceramic sleeve and permanent crown is applied.

The present invention will now be further described with reference to the incoming drawings in which: Figure 1 shows a dental implant commonly used in the field at present; Figure 2 shows a dental implant according to the present invention; Figures 3A and 3B show acrylic and ceramic sleeve portions respectively; Figure 3C shows a further example of a sleeve portion; Figure 4 shows the treated portion of the patient's mouth at an interim point of the first stage surgery; Figure 5 shows the treated portion of the patient's mouth after the first stage of surgery; and Figure 6 shows the treated portion of the patient's mouth after the second stage of surgery.

Figure 2 shows a dental implant 30 according to the present invention. The dental implant 30 comprises a cone shaped implant portion 31 that is designed to interface with the jaw bone of the patient. The implant portion 31 is provided with conventional screw threaded portions 32 to enable the implant portion 31 to be screwed into the jaw bone of the patient. At the upper end of the cone shaped implant portion 31 there is a surface 33 known as the implant table which, in use, is aligned with the upper surface of the jaw-bone. For some situations it may be desirable for the implant table 33 to be scalloped as shown in Figure 6. The portion 30A ofthe implant 30 adjacent to the implant table 33 may be milled as shown in Figure 6 or smooth as shown in Figure 4. An abutment portion 34 extends from the surface 33. The abutment portion 34 tapers away from the surface 33 and is provided with a milled chamfer 35 at the point where it interfaces with the implant portion 31 at the surface 33. The distal portion of the abutment portion 34 is rectangular and is provided with a groove 37. The groove 37 interacts with an insertion tool to provide a temporary engagement between the tool and the implant 30 and co-operates with a sleeve 40 to be described subsequently. The milled chamfer portion 35 is designed to interface, in use, with the sleeve 40 as shown in Figures 3A to 3C.

Figure 3A shows a sleeve 40 made from acrylic. The lip 41 is designed to interface with the milled chamfer 35 of the implant 30. The outer surface of the sleeve 40 comprises a flared portion 42 that, in use, passes through the gum of the patient. This flared portion 42 provides an uplift in size to enable a smooth transition to be made with a temporary crown 75. The distal end 43 of the sleeve portion 40 is closed and tapers at a more shallow angle than the flared portion 42 so that the widest part of the sleeve 40 is intermediate its ends. This part of the sleeve 40 is arranged to be positioned at the upper surface of the gum, in use. The tapering of the distal portion 43 and the closed end allows the inner part of the distal portion 43 to interface with the distal portion of the implant 30. The inside of the acrylic sleeve 40 includes a projecting rib (not shown) which co-operates with the groove 37 to provide a "snap-fit" connection between the sleeve 40 and the implant 30.

Figure 3B shows a ceramic sleeve portion that is designed for interfacing with a permanent crown. The milled internal collar portion 41 is designed to fit precisely onto the milled chamfer 35 and the abutment portion 34 of the implant 30. The sub-gingival flared portion 42 is a highly polished ceramic. The distal portion 43 is provided with a roughened area of ceramic onto which the crown 79 is moulded and fixed. This allows the number of pieces required in the implant as a whole to be reduced. This has evident advantages and there are fewer interfaces that are susceptible to bacterial build-up.

Figure 3C shows a further example of a sleeve portion that is designed for replacement of anterior teeth. This sleeve shape will be used in either acrylic or ceramic. The shape is dictated by the gap in the mouth that the tooth must fill and the shape of the relevant portion of the jaw bone and gum line. This sleeve is designed for use in an anterior tooth and therefore it has a scalloped internal collar portion 41 and the portion 42 is not flared. The scalloped internal collar portion 41 interfacing, in use, with a scalloped implant table 33 on the implant portion 30. Furthermore, the distal portion 43 of the sleeve 40 does not extend perpendicular to the portion 42. It will be readily understood by a man skilled in the art that any of these features may be combined to form a range of sleeves with differently angled distal portions 43, differing angle of flare of portion 42 and a scalloped or flat implant table 33.

The implant 30 is first screwed into the jaw-bone of the patient as shown in Figure 4. It is evident that the implant table 33 lies at the upper level 72 of the jaw bone. The ceramic sleeve is then fitted onto the implant and am impression taken of the inside of the patient's mouth. Once the impression compound has hardened it is removed, together with the ceramic sleeve and sent to a Dental Laboratory where a permanent ceramic crown is moulded onto the ceramic sleeve. Naturally, this takes account of the patient's adjacent teeth, gum line and bite. The temporary acrylic sleeve 40 is then snap-fitted onto the implant 30. The sleeve 40 extends through the gum with the widest part of the sleeve being aligned with the gum margin 73. The distal portion 43 ofthe sleeve 40 extends above the gum margin 73.

A temporary acrylic crown 75 is then formed over the acrylic sleeve 40 as shown schematically in Figure 4 and fully in Figure 5. This completes the first stage of surgery.

Subsequently, as shown in Figure 6, after the permanent crown has been made in the laboratory, the temporary crown 75 is removed and the permanent crown 79 is cemented in place. Cement collects in the groove 37 and this helps to secure the permanent crown in place.

Claims

1. A dental implant for securing a crown, the implant comprising: an implant portion for interfacing with a jaw bone of a patient, an integral abutment portion tapering from the implant portion to form a distal portion that is arranged to interface with a crown.

2. The implant according to claim 1, wherein the abutment portion is formed in one of a plurality of different lengths and angles relative to the implant portion.

3. The implant according to any of the preceding claims, wherein the abutment portion tapers.

4. The implant according to claim 3, wherein the tapered section of the abutment portion has a milled chamfer with which a sleeve supporting a crown interfaces, in use.

5. The implant according to claim 4, wherein the milled chamfer is arranged to align with the upper surface of the patient's gum, in use.

6. A dental implant system comprising: an implant according to any of claims 1 to 5; and a sleeve for engaging with the abutment portion of the implant and further comprising a distal portion on which a crown is formed.

7. The implant according to claim 4 or claim 5 or a dental implant system according to claim 6, wherein the sleeve has a scalloped implant table.

8. The implant according to claim 4 or claim 5 or a dental implant system according to claim 6 or claim 7, wherein the sleeve comprises a flared portion and a distal portion.

9. The implant according to claim 4 or claim 5 or a dental implant system according to any of claims 6 to 8, wherein the sleeve is acrylic and the crown is a temporary crown.

10. The implant according to claim 4 or claim 5 or a dental implant system according to any of claims 6 to 8, wherein the sleeve is ceramic and the crown is a permanent crown.

11. The implant according to claim 4 or claim 5 or a dental implant system according to any of claims 6 to 10, wherein the sleeve has a closed distal end.

12. The implant according to claim 4 or claim 5 or a dental implant system according to any of claims 6 to 10, wherein the sleeve has an open distal end.

13. The implant according to claim 4 or claim 5 or a dental implant system according to any of claims 6 to 12, wherein the sleeve comprises a milled post portion for engaging with the abutment portion of the implant.