WO2011027975A2

WO2011027975A2 - Dental implant assembly having settlement-preventing step

Info

Publication number: WO2011027975A2
Application number: PCT/KR2010/004897
Authority: WO
Inventors: Hyeon Cheol Jeong; Byung Kook Kim; Mu Yong Park; Tae Gwan Eom
Original assignee: Osstemimplant Co., Ltd.
Priority date: 2009-09-01
Filing date: 2010-07-26
Publication date: 2011-03-10
Also published as: WO2011027975A3; KR101067668B1; KR20110024189A

Abstract

The present invention relates to a dental implant assembly having a settlement-preventing step so as to prevent an abutment from settling due to a vertical load caused by mastication after the dental implant assembly is implanted. The present invention provides a dental implant assembly, which is implanted in an oral cavity to replace a lost tooth and includes a fixture implanted in an alveolar bone, an abutment coupled with the fixture to locate a dental prosthesis on the fixture, and a settlement-preventing means for preventing settlement of the abutment by being in contact with the fixture when the abutment is coupled with the fixture.

Description

DENTAL IMPLANT ASSEMBLY HAVING SETTLEMENT-PREVENTING STEP

The present invention relates to a dental implant assembly used for recovering a lost tooth of a patient, and more particularly, to a dental implant assembly having a settlement-preventing step so as to prevent an abutment from settling due to a vertical load caused by mastication after the dental implant assembly is implanted.

An implant is a substitute for recovering lost tissues of a human body. In the field of dentistry, an implant is generally used as a substitute in which a fixture is implanted in and adhered to an alveolar bone from which a tooth root of a natural tooth is taken out such that the fixture may replace a tooth root of a lost tooth, and then an artificial tooth is fixed to the fixture such that the original function of the lost tooth may be recovered.

Such a dental implant may be classified in various ways in accordance with their coupling methods between the artificial tooth and the tooth root thereof. Among them, there is a screw-type implant using a coupling power of a screw, and the conventional screw-type implant system (or screw-type implant assembly) is composed of a fixture, an abutment and a dental prosthesis.

The fixture is implanted in the alveolar bone and plays a role of fixing the entire implant system. The fixture is made of titanium or the like, which is excellent in biocompatibility, for satisfying its compatibility with osseous tissues of a human body. The abutment is coupled with the fixture and plays a role of fixing and supporting a dental prosthesis. The dental prosthesis is made to be shaped as a tooth through several processes such as impression acquisition, work model preparation, waxing, investing and annealing.

Surgical procedure for the implant system configured as above generally includes: a fixture implanting step for implanting a fixture serving as an implant understructure, an impressing acquisition and work model preparation step, a waxing and inner crown casting step, a prosthesis molding step for molding a prosthesis, and a prosthesis adhering step for coupling the prosthesis with an outer crown by means of a cement.

Fig. 1 is a side sectional view showing a conventional implant assembly. As shown in Fig. 1, the conventional implant assembly includes a fixture 1 implanted in an alveolar bone, an abutment 5 coupled with the fixture 1, and a dental prosthesis (not shown) fixed to the fixture 1 by means of the abutment 5. The abutment 2 may be fixed to the fixture 1 by means of an abutment screw 3 which passes through the abutment 2.

According to the conventional implant assembly as described above, when the abutment 2 is fixed to the fixture 1, a lower outer circumferential slope surface 6 of the abutment 2 is in contact with an upper inner circumferential slope surface 5 of the fixture 1, thereby supporting a vertical load against the abutment 2.

However, in such a conventional vertical load supporting structure, the abutment 2 may settle, thereby causing inexact occlusion problem. Also, the settlement of the abutment 2 may reduce a preload of the abutment screw 3, which may result in releasing the screw.

In addition, in case of using a bridge-type prosthesis in which a plurality of prostheses are connected to each other, if any one of the plurality of abutments settle, a stress is focused to a connection portion between adjacent prostheses, which may break down the prosthesis or the fixture.

The present invention is conceived to solve the aforementioned problems in the prior art. An object of the present invention is to provide a dental implant assembly having a settlement-preventing step, which may be engaged with a fixture and an abutment, so as to prevent the abutment from settling due to a vertical load after the dental implant assembly is implanted.

According to an aspect of the present invention for achieving the objects, there is provided a dental implant assembly that is implanted in an oral cavity to replace a lost tooth, the dental implant assembly including: a fixture implanted in an alveolar bone; an abutment coupled with the fixture to locate a dental prosthesis on the fixture; and a settlement-preventing means for preventing settlement of the abutment by being in contact with the fixture when the abutment is coupled with the fixture.

The settlement-preventing means preferably includes a settlement-preventing step formed at an outer circumference of the abutment so that the settlement-preventing step is locked to an upper inner circumferential edge of the fixture.

The settlement-preventing step preferably convexly protrudes on the outer circumference of the abutment in a ring shape.

The settlement-preventing means may include: a settlement-preventing concavity concavely formed in an inner circumference of the fixture; and a settlement-preventing convexity convexly formed on the outer circumference of the abutment, which is inserted into the fixture, at a location corresponding to the settlement-preventing concavity.

Also, the settlement-preventing means may include: a settlement-preventing convexity convexly formed on an inner circumference of the fixture; and a settlement-preventing concavity concavely formed in the outer circumference of the abutment, which is inserted into the fixture, at a location corresponding to the settlement-preventing convexity.

The settlement-preventing concavity is preferably formed in a ring shape, and the settlement-preventing convexity is formed in a ring shape or as protrusions spaced apart by regular intervals.

The settlement-preventing means preferably includes a settlement-preventing bottom formed at a lower end of an abutment insert portion of the abutment so that a lower end of the abutment is in contact with the settlement-preventing bottom.

The fixture may include an outer circumferential thread formed on an outer circumferential surface thereof to allow insertion and coupling into an alveolar bone; an inner circumferential thread formed on a lower portion of an inner circumferential surface thereof to be coupled with an abutment screw; and an abutment insert portion formed at an upper portion of the inner circumferential surface, thereby having a diameter greater than the inner circumferential thread so that a lower end of the abutment is inserted therein.

The abutment may include a through hole formed therein so that the abutment screw passes therethrough; and a lower end having a diameter and shape so that the lower end is inserted into the abutment insert portion of the fixture.

The abutment insert portion may have a first slope with an inner diameter gradually decreased downwards from an upper inner circumferential edge of the fixture, and the lower end of the abutment may have a second slope with an outer diameter gradually decreased downwards. The second slope is in contact with the first slope when the abutment is coupled with the fixture.

According to the present invention so constructed, it is possible to provide the dental implant assembly having the settlement-preventing step, which may be engaged with the fixture and the abutment, so as to prevent the abutment from settling due to the vertical load after the dental implant assembly is implanted.

It is possible to prevent the abutment from settling by means of the settlement-preventing step in the dental implant assembly according to the present invention, thereby ensuring its exact occlusion while the implant assembly is used. In addition, it is possible to prevent the preload of the abutment screw from being reduced, thereby keeping the coupled state of screws.

Further, when the dental implant assembly according to the present invention is used, even if a bridge-type prosthesis is used, it is possible to prevent the stress from being focused on the connection portion between adjacent prostheses due to the settlement of at least one abutment, thereby preventing the prosthesis and the fixture from being broken down.

Fig. 1 is a side sectional view showing a conventional implant assembly;

Fig. 2 is a side sectional view showing an implant assembly according to a first embodiment of the present invention;

Fig. 3 is a side sectional view showing an implant assembly according to a second embodiment of the present invention;

Fig. 4 is a side sectional view showing an implant assembly according to a modification of the second embodiment of the present invention; and

[Rectified under Rule 91 15.09.2010]
Fig. 5 is a side sectional view showing an implant assembly according to a third embodiment of the present invention.

[Explanation of Reference Numerals for Major Portions Shown in Drawings]

10: Fixture

11: Outer circumferential thread

12: Inner circumferential thread

13: Abutment insert portion

14: First slope

20: Abutment

21: Through hole

22: Lower end

23: Second slope

30: Abutment screw

41: Settlement-preventing step

42: Settlement-preventing concavity

43: Settlement-preventing convexity

44: Settlement-preventing bottom

Hereinafter, a preferred embodiment of a dental implant assembly according to the present invention will be described in detail with reference to the accompanying drawings.

Fig. 2 is a side sectional view showing an implant assembly according to a first embodiment of the present invention. As shown in Fig. 2, the implant assembly according to the first embodiment of the present invention includes a fixture 10 implanted in an alveolar bone, an abutment 20 coupled with the fixture 10 so that a dental prosthesis may be located on the fixture 10, and a settlement-preventing means capable of preventing settlement of the abutment 20 when the abutment 20 is coupled with the fixture 10. The abutment 20 may be fixed to the fixture 10 by means of an abutment screw 30 which passes through the abutment 20.

The fixture 10 may includes an outer circumferential thread 11, formed on an outer circumferential surface, for allowing insertion and coupling into the alveolar bone; an inner circumferential thread 12, formed on a lower portion of an inner circumferential surface, with which the abutment screw 30 is coupled; and an abutment insert portion 13, formed at an upper portion of the inner circumferential surface, which has a diameter greater than the inner circumferential thread 12 so that a lower end of the abutment 20 may be inserted therein.

The abutment insert portion 13 may have a first slope 14 which is tapered so that its inner diameter is gradually decreased downwards from an upper inner circumferential edge of the fixture 10.

Also, the abutment 20 may include a through hole 21 formed therein so that the abutment screw 30 may pass through it, and a lower end 22 having a diameter and shape corresponding to the abutment insert portion 13 of the fixture 10 so that it may be inserted into the abutment insert portion 13.

The lower end 22 of the abutment may have a second slope 23 which is tapered so that the outer diameter of the second slope 23 is gradually decreased downwards. The second slope 23 may be in contact with the first slope 14 of the fixture 10 when the abutment 20 is coupled with the fixture 10.

In particular, according to the first embodiment of the present invention, as the settlement-preventing means, a settlement-preventing step 41 may be formed on the abutment 20 so that the step is locked at the upper inner circumferential edge of the fixture 10. The settlement-preventing step 41 of the first embodiment serving as the settlement-preventing means preferably protrudes upwards over the second slope 23 formed at the lower outer circumferential surface of the abutment 20.

The protruding settlement-preventing step 41 of the first embodiment is contacted with the upper inner circumferential edge of the fixture 10, so it may securely prevent settlement of the abutment 20.

The settlement-preventing step 41 may be convex in an oval shape on the outer circumference of the abutment 20, or it may also be formed as protrusions convexly formed at regular intervals.

Fig. 3 is a side sectional view showing an implant assembly according to a second embodiment of the present invention. Compared with the above-explained implant assembly of the first embodiment in which the settlement-preventing means includes the settlement-preventing step 41 formed on the abutment 20 so that it is locked to the upper inner circumferential edge of the fixture 10, the second embodiment is different from the first embodiment in that the settlement-preventing means in the implant assembly of the second embodiment includes a settlement-preventing concavity 42 concavely formed in the first slope 14 of the fixture 10, and a settlement-preventing convexity 43 convexly formed on the abutment 20 at a location corresponding to the second slope 23.

Thus, in Fig. 3 showing the fixture of the second embodiment, the same element as in the first embodiment is designated by the same reference numeral as in Fig. 2, and it will not be described in detail again.

Fig. 3 illustrates that the settlement-preventing concavity 42 and the settlement-preventing convexity 43 are formed at the first slope 14 of the fixture 10 and the second slope 23 of the abutment 20 as the settlement-preventing means, respectively, however the settlement-preventing concavity 42 and the settlement-preventing convexity 43 need not be always formed onto the slopes.

Also, although the settlement-preventing concavity 42 is formed at the first slope 14 of the fixture 10 in a ring shape, the settlement-preventing convexity 43 may be formed at the second slope 23 of the abutment 20 in a ring shape or formed as protrusions spaced apart by regular intervals.

In addition, only if the insertion of the abutment screw 30 into the abutment 20 is not disturbed, the settlement-preventing convexity 43 may be formed in the inner circumference of the fixture 10, and the settlement-preventing concavity 42 may be formed in the outer circumference of the abutment 20, as shown in Fig. 4.

Fig. 5 is a side sectional view showing an implant assembly according to a third embodiment of the present invention. Compared with the above-explained implant assembly of the first embodiment in which the settlement-preventing means includes the settlement-preventing step 41 formed on the abutment 20 so that it is locked to the upper inner circumferential edge of the fixture 10, the third embodiment is different from the first embodiment in that the settlement-preventing means in the implant assembly of the third embodiment includes a settlement-preventing bottom 44 formed at a lower end of the abutment insert portion 13 of the fixture 10 so that the lower end of the abutment 20 is locked thereto.

Thus, in Fig. 5 showing the fixture of the third embodiment, the same element as in the first embodiment is designated by the same reference numeral as in Fig. 2, and it will not be described in detail again.

Referring to Fig. 5, it is illustrated that the lower end of the abutment 20 does not have a horizontal plain but is inclined toward the outer circumference, and the settlement-preventing bottom 44 of the fixture 10 is also inclined with the same angle correspondingly. However, various shapes or designs may be used instead of such inclined shapes only if the lower end of the abutment 20 and the settlement-preventing bottom 44 of the fixture 10 may have corresponding shapes.

Hereinafter, experimental results obtained by comparatively analyzing the dental implant assembly according to the present invention and the conventional dental implant assemblies are explained with reference to Tables 1 and 2.

With respect to the dental implant assembly according to the first embodiment of the present invention (i.e., a present example) and a conventional dental implant assembly (i.e., a comparative example), a static load of the same magnitude was applied, and then an amount of settlement of the abutment was measured. Also, after loads having the same magnitude were repeatedly applied as much as the same number (500 times), an amount of settlement of the abutment was measured. Comparison results of the measured values are shown in Table 1.

The dental implant assembly according to the first embodiment of the present invention had the same size as the conventional dental implant assembly, and the applied static load and repeated load were respectively 500N.

Table 1

	Amount of settlement after a static load of 500N is applied once (㎛)	Amount of settlement after loads of 500N were repeatedly applied 500 times (㎛)
Present Example	1.4	2.4
Comparative Example	8.0	12.2

As seen from Table 1, it could be found that the dental implant assembly according to the present invention exhibits a remarkably small amount of settlement in comparison to the conventional dental implant assembly after applying not only a static load but also repeated loads thereto.

With respect to the dental implant assembly according to the first embodiment of the present invention (i.e., a present example) and a conventional dental implant assembly (i.e., a comparative example), a load of the same magnitude was applied (sink-down test), and then a torque required for releasing the abutment screw was measured. Also, after repeated loads of the same frequency (14 Hz) and the same magnitude (250N) were applied as much as the same number (10,000 times) (cantilever fatigue test), an amount of settlement of the abutment was measured. Comparison results of the measured values are shown in Table 2.

Table 2

	Torque required for releasing an abutment screw after the settlement test (Ncm)	Torque required for releasing an abutment screw after the cantilever fatigue test (Ncm)
Present Example	19.0	17.6
Comparative Example	9.5	8.2

As seen from Table 2, it could be found that the dental implant assembly according to the present invention requires a remarkably high torque for releasing the abutment screw in comparison to the conventional dental implant assembly even after a load is applied thereto.

In other words, if the dental implant assembly of the present invention is used, a preload of the abutment screw is not decreased since an amount of settlement is small rather than conventional cases, and accordingly the implant assembly may be maintained in a state that a torque required for releasing the abutment screw is not reduced. Thus, it is possible to prevent the abutment screw from being released unintentionally.

The dental implant assembly according to the present invention has been described and illustrated as above, but the present invention is not limited to the description and drawings, but various modifications and changes can be made thereto within the scope of the invention defined by the claims.

Claims

A dental implant assembly that is implanted in an oral cavity to replace a lost tooth, the dental implant assembly comprising:

a fixture implanted in an alveolar bone;

an abutment coupled with the fixture to locate a dental prosthesis on the fixture; and

a settlement-preventing means for preventing settlement of the abutment by being in contact with the fixture when the abutment is coupled with the fixture.
The dental implant assembly as claimed in claim 1, wherein the settlement-preventing means includes a settlement-preventing step formed at an outer circumference of the abutment so that the settlement-preventing step is locked to an upper inner circumferential edge of the fixture.
The dental implant assembly as claimed in claim 2, wherein the settlement-preventing step convexly protrudes on the outer circumference of the abutment in a ring shape.
The dental implant assembly as claimed in claim 1, wherein the settlement-preventing means includes a settlement-preventing concavity concavely formed in an inner circumference of the fixture; and a settlement-preventing convexity convexly formed on the outer circumference of the abutment, which is inserted into the fixture, at a location corresponding to the settlement-preventing concavity.
The dental implant assembly as claimed in claim 1, wherein the settlement-preventing means includes a settlement-preventing convexity convexly formed on an inner circumference of the fixture; and a settlement-preventing concavity concavely formed in the outer circumference of the abutment, which is inserted into the fixture, at a location corresponding to the settlement-preventing convexity.
The dental implant assembly as claimed in claim 1, wherein the settlement-preventing means includes a settlement-preventing bottom formed at a lower end of an abutment insert portion of the abutment so that a lower end of the abutment is in contact with the settlement-preventing bottom.
The dental implant assembly as claimed in claim 4 or 5, wherein the settlement-preventing concavity is formed in a ring shape, and the settlement-preventing convexity is formed in a ring shape or as protrusions spaced apart by regular intervals.
The dental implant assembly as claimed in any one of claims 1 to 6,

wherein the fixture includes an outer circumferential thread formed on an outer circumferential surface thereof to allow insertion and coupling into an alveolar bone; an inner circumferential thread formed on a lower portion of an inner circumferential surface thereof to be coupled with an abutment screw; and an abutment insert portion formed at an upper portion of the inner circumferential surface, thereby having a diameter greater than the inner circumferential thread so that a lower end of the abutment is inserted therein,

wherein the abutment includes a through hole formed therein so that the abutment screw passes therethrough; and a lower end having a diameter and shape so that the lower end is inserted into the abutment insert portion of the fixture, and

wherein the abutment insert portion has a first slope with an inner diameter gradually decreased downwards from an upper inner circumferential edge of the fixture, and the lower end of the abutment has a second slope with an outer diameter gradually decreased downwards, the second slope being in contact with the first slope when the abutment is coupled with the fixture.