WO2008093994A1

WO2008093994A1 - Dental implant apparatus

Info

Publication number: WO2008093994A1
Application number: PCT/KR2008/000556
Authority: WO
Inventors: Sung-Won Park
Original assignee: Sung-Won Park
Priority date: 2007-01-31
Filing date: 2008-01-30
Publication date: 2008-08-07
Also published as: KR100799368B1

Abstract

The present invention relates to a dental implant apparatus, and more particularly, to a dental implant apparatus including a fixture binding to a human jawbone to form an artificial dental root, a crown forming the exterior of an artificial tooth, and an abutment of which one side binds to the fixture and the other side binds to the crown, wherein the abutment includes: an abutment body binding to the fixture, and a intermediate member disposed between the abutment body and the crown, in which the exterior of the intermediate member binds to the crown, and the interior of the intermediate member binds to the abutment body by a resin, such that in the case where an impact is transferred from outside to the resin, the resin is broken and separated from the abutment body.

Description

DENTAL IMPLANT APPARATUS

TECHNICAL FIELD

The present invention relates to a dental implant apparatus, and more particularly, to a dental implant apparatus that can easily be separated from a human body upon exertion of an excessive external force on the artificial tooth temporarily implanted in the human body.

BACKGROUND ART Dental implants conventionally refer to an artificial dental structure formed by planting an artificial dental root fixture on an area of a partially or entirely lost tooth, to adhere to the alveolar bone, and fixing a dental prosthesis on the artificial dental root. The term implant can be used in a broad context including a method of such a dental operation, and narrowly, it can also be used synonymously with the fixture. However, the "implant" in the present specification can be generally interpreted as an artificial dental structure.

Conventionally, an implant is composed of a fixture fused with the jawbone of the body to form an artificial dental root, a crown forming the exterior of the artificial tooth, and an abutment binding one side thereof with the fixture and another side with the crown.

An implant can be operated only on the damaged part without damaging the teeth near the damaged tooth or the surrounding tissue, and the implant supports the bone tissue to slow the absorption of bone tissue, and can superficially form an almost identical appearance with natural teeth. Therefore, implants have recently been used widely as a method of dental operation for recovering damaged or lost teeth.

Such implants can be divided into a screw-retained type and a cement-retained type, depending on the structure and operational method of the implant.

<Screw-retained Type> A screw-retained type has been applied since implants were first developed, and are still used to this day. The screw-retained type is basically a method of fixing the crown to the fixture and the abutment using a screw, which can be easily detached or replaced because the crown is bound by the screw. i The screw-retained type can be largely divided into 2 types. One is a type in which a crown fused on an abutment called a UCLA abutment is directly connected to the fixture, and another is a type in which an abutment called a intermediate abutment is connected to the fixture, and then an upper gold cylinder is connected on top of the intermediate abutment, forming a final crown, being mounted on or separated from the intermediate abutment.

Fig. 1 is a cross-sectional view illustrating a screw-retained type implant using a conventional UCLA abutment.

Referring to FIG. 1A, the screw-retained type implant apparatus 10 using the UCLA abutment includes a fixture 12 implanted on the jawbone and an abutment 14 forming a single body with a crown 18 and disposed on the fixture 12. The crown 18 and the abutment 14 are formed into a single body on the exterior, and a hole that passes through the center is formed therein.

A screw 16 is fastened on the fixture 12 through the hole, so that the crown 18 and the abutment 14 are fixed to the fixture 12.

Fig. 2 is a cross-sectional view illustrating a screw-retained type implant apparatus 10 using a conventional intermediate abutment.

Referring to FIG. 2, the implant apparatus 20 using a intermediate abutment includes a fixture 22, a intermediate abutment 24, and an upper abutment 26 forming a fused body with a crown 28 and disposed on the intermediate abutment 24. The intermediate abutment 24 includes a hole corresponding to a first screw 23, which is fastened to the fixture 24 through the intermediate abutment 24, so that the intermediate abutment 24 is fixed to the fixture 22.

A second screw 25 is inserted into a hole passing through the crown 28 and the upper abutment 26, and the second screw 25 is fastened to the screw hole formed on the first screw 23, so that the crown 28 and the upper abutment 26 are fixed on the intermediate abutment 24.

As shown in FIGS. 1 and 2, the lower part of the final crown 18 and 28 encloses already existing parts (such as, the UCLA abutment 14, the upper abutment 26) fit for the fixture of the upper part of the intermediate abutment, which are formed together when the crown is molded, forming a fused body with the crown. The best feature of the screw-retained type is that the screw hole is formed on the occlusal surface of the crown, and that the bond between the screw and the fixture can be controlled using the screw hole.

However, the screw-retained type has the following drawbacks. In order to perform the implant operation using the screw-retained type, the fixture is planted on the jawbone, and it then takes the fixture about 3-4 months to be completely attached to the jawbone and the bone tissue. Then, once the fixture is completely attached to the bone tissue, the abutment and the crown can be installed on the fixture. As such, the individual who has received the implant using the screw-retained type should wait 3 to 4 months to prepare the temporary teeth, and therefore has to lead life without the teeth for a relatively long period of time.

Moreover, the crown of the screw-retained type must form a passive fit with the fixture disposed under the crown, thereby requiring near precise processing of the crown. Therefore, the screw-retained type may be complex in terms of its manufacturing method, and may consume excessive time and cost of manufacturing.

Furthermore, if the implant is not processed or installed perfectly, various types of stress may be exerted to the implant, whereby an excessive amount of stress may likely cause bone loss around the implant, or a fracture of the crown or the implant itself. A common problem arising from the screw-retained type is the loosening of the screw. According to some reports, loosening of the screw occurred in about 25-30% of the implant apparatuses on which the screw-retained method was performed. That is, an implant apparatus without a good fit causes the screw to be stretched even at a small occlusion force compared to that with a good fit, creating a permanent change and allowing the screw to be loosened easily.

In order to overcome the drawbacks, the screw-retained type must be fixed by manual fitting. Producing an implant apparatus forming a manual fitting within the mouth first requires a preparation of a precise working cast, and then manufacture of a precise implant apparatus thereon. Precise impression making, preparation of a working cast and a crown must be performed in order to make an accurate and precise working cast. However, considering the contraction and alteration of materials, such an operation requires a highly skilled worker, and requires much treatment and production time due to the characteristics of the manufacturing process. Hence, the treatment cost is not only expensive, but the production cost is also expensive, not to mention the material cost. Therefore, the implant apparatus using the screw-retained type has a high overall cost.

<Cement-retained Type>

A cement-retained type, compared to the screw-retained type, refers to a method in which an abutment is fixed on a fixture using a screw, then a separately prepared crown is disposed on the fixed abutment, and then dental cement is interposed between the two parts to attach the crown and the abutment. FIG. 3 is a diagram illustrating a conventional cement-retained implant apparatus.

Referring to FIG. 3, the implant apparatus 30 using the cement-retained type includes a fixture 32, an abutment 34, and a crown 38. The abutment 34 in which a screw hole is formed is disposed on the fixture 32 planted on the jaw bone, and the abutment 34 is fixed by fastening the screw 36 on the fixture 32 through the screw hole. The crown 38 is joined to the fixed abutment 34, and dental cement 37 is applied in between to attach the abutment 34 and the crown 38. Unlike the screw-retained type, the crown 38 and the abutment 34 are prepared separately, and then the crown 38 and the abutment 34 are attached together by using the dental cement 37.

Thus, the implant using the conventional cement-retained type has an aesthetic advantage in that the junction of the crown does not have a screw hole. Therefore, unlike the implant apparatus using the screw-retained type, the artificial tooth is not visibly noticeable, and can have a natural appearance like a real tooth, but once the crown is installed, the crown cannot be unscrewed to separate it from the implant.

The cement-retained type provides a solution to all the problems related to the screw-retained type. That is, the cement-retained type can easily form a passive fit between the fixture and the crown, resulting in a reduction in the stress applied to the fixture when attaching the crown, there is less occurrence of screw loosening, and a simpler clinical procedures and manufacturing process can be performed, saving time and production cost. Above all, the biggest advantage of the cement-retained type is that the unfitting between the crown and the abutment can be solved by simply having a space between the crown and the abutment, and the dental cement can be charged to the space. Compared to the screw-retained type which requires high-level precision, the cement- retained type has simple processes of impression and construction, and a manual fitting between the implant and the crown can be achieved, as long as a few rules are observed. Particularly, in the case of a cement-retained type, the fixture can be planted on the jawbone without forming an impression, and the abutment and the already-prepared crown can be installed on top of the fixture. Therefore the individual receiving the implant does not have to live without teeth for 3 to 4 months as in the case of the screw-retained type implant, enjoying life as before the operation. Of course, the abutment and the crown installed temporarily will later be ultimately replaced by a precisely processed crown. However, such a conventional cement-retained type has the following drawbacks.

First, in the initial period of treatment when the crown is installed temporarily, the patient chews food using the crown carefully, but as the surgery wound is gradually healed and the implant apparatus becomes robustly attached to the jawbone and the bone tissue, the patient may feel safer to chew harder food or apply a strong impact accidentally during daily life. Such an impact is directly transferred to the fixture from the crown through the abutment, shifting the position of the fixture, which is not yet completely healed, from its original position. Due to such a shift of the fixture, the patient has to revisit the dentist for more surgery to correctly plant the fixture on the jawbone.

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL PROBLEM

The present invention provides a dental implant apparatus which, in the case where a certain impact is applied to a temporarily installed crown, does not directly transfer the impact to a fixture.

TECHNICAL SOLUTION

According to an aspect of the present invention, there is provided a dental implant apparatus including: a fixture binding to a human jawbone to form an artificial dental root; a crown forming the exterior of the artificial tooth; and an abutment of which one side binds to the fixture and the other side binds to the crown, wherein the abutment comprises: an abutment body binding to the fixture; and a intermediate member disposed between the abutment body and the crown, in which the exterior of the intermediate member binds to the crown, and the interior of the intermediate member binds to the abutment body by a resin, such that in the case where an impact is transferred from outside to the resin, the resin is broken and separated from the abutment body.

The resin of the dental implant apparatus may be polymethyl methacrylate or polycarbonate.

The intermediate member of the dental implant apparatus may be made of a hard material without substantially elastic deformation. The intermediate member of the dental implant apparatus may has a frusto-conical exterior shape in the area that binds to the crown.

According to the dental implant apparatus, the area of the abutment body to which the intermediate member is attached may include a frusto-conical exterior.

According to the dental implant apparatus, a hooking part may be prepared on the intermediate member at the articulation with the abutment body, and a hooking holder may be prepared on the abutment body, which prevents separation of the intermediate member from the abutment body by being interlocked on the hooking part of the intermediate member while the intermediate member is attached to the abutment body.

ADVANTAGEOUS EFFECTS

According to the dental implant apparatus of the present invention, in the case where an impact of a certain level is applied to the temporarily installed crown, the crown is separated from the abutment body, and thus the impact is not transferred to the fixture, which prevents a re-implanting operation of the fixture.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an embodiment of a screw-retained implant apparatus according to the prior art; FIG. 2 is a diagram illustrating another embodiment of a screw-retained implant apparatus according to the prior art;

FIG. 3 is a diagram illustrating a cement-retained implant according to the prior art; FIG. 4 is a diagram illustrating the implantation of the implant apparatus of FIG. 3;

FIG. 5 is an exploded cross-sectional view of an implant apparatus according to an embodiment of the present invention;

FIG. 6 is a diagram illustrating the implantation of the implant apparatus of FIG. 5; FIG. 7 is a diagram illustrating a separation of a crown and a intermediate member of the implant apparatus from an abutment body;

FIG. 8 is a diagram illustrating a sloped implantation of the implant apparatus according to FIG. 5.; and

FIG. 9 is a diagram illustrating another embodiment of the implant apparatus according to the present invention.

< Explanation of reference numerals designating the major elements of the Drawings> 100... implant apparatus 110... fixture

120... crown 130... abutment 140... abutment body 150... intermediate member

BEST MODE

Hereinafter, the present invention will be described more fully with reference to the accompanying drawings, in which preferred embodiments of the invention are shown.

The dental implant apparatus 100 according to an embodiment of the present invention includes a fixture 110, a crown 120, and an abutment 130.

The fixture 110 binds to the jawbone of the human body to form an artificial dental root. The fixture 110 is formed of a titanium alloy, and a screw thread 111 is formed on the exterior surface. Using such a screw thread 111 prepared thereon, the fixture 110 can pierce into the jawbone, and after reaching the jawbone, it is adsorbed with the surrounding tissues of the human body, over a long period of time. Adsorbing to tissues of the human body, the fixture 110 fuses with the jawbone, and functions as an artificial dental root to stably support the abutment 130 and the crown 120. Here, the screw thread 111 not only allows easy entrance of the fixture 110 to the jawbone, but it also functions as a tissue attachment forming a wide surface area of adsorption with tissues of the human body. On the upper part of the fixture 110, a step 112 binding to the abutment 130 is prepared, and in the center, a first screw hole 113 is formed at a predetermined depth.

The crown 120 forms the outside appearance of the artificial tooth, and the outside appearance is identical to that of a normal tooth, and its interior is empty. The crown 120 is filled with cement 121. The cement 121 filling the crown 120 not only maintains the shape of the crown, but also bonds the crown 120 with the abutment 130.

The abutment 130 is formed of an abutment body 140 and a intermediate member 150.

The abutment body 140 binds to the fixture 110. The intermediate member 150 is attached to the upper portion of the abutment body 140, and the upper portion of the fixture 110 binds to the lower portion of the abutment body 140.

The part of the abutment body 140 on which the intermediate 150 is attached has a frusto-conical exterior shape. On the lower portion of the abutment body 140, there is formed a step coverage 112 complementing a step 112 provided on the upper portion of the fixture 110. Once the step coverage 141 of the abutment body 140 is locked to the step 112 of the fixture 110, the abutment body 140 is suspended from moving in a perpendicular direction to the axis of the fixture 110.

The abutment body 140 includes a second screw hole 142 connected from the top center part to the bottom center. The second screw hole 142 is provided on the abutment body 140 so that the screw 160 can be fastened to the first screw hole 113 through the second screw hole 142. A supporting step 143 is provided on the second screw hole 142 that supports the head of the screw 160.

The intermediate member 150 is disposed between the abutment body 140 and the crown 120. The exterior of the intermediate member 150 binds with the interior of the crown 120. Moreover, the interior of the intermediate member 150 is bound to the abutment body 140 by a resin 144, such that when an external impact is applied to the crown 120, the impact passes through the intermediate member 130 to the resin 144, and the resin 144 is broken, and thus the intermediate member 130 is separated from the abutment body 140, preventing a direct transfer of the external impact to the abutment body 140.

Such a intermediate member 150 forms an overall frusto-conical exterior shape, and a space is provided in the interior so that the top portion of the abutment body 140 can be bound in the space. The resin 144 that attaches the abutment body 140 to the intermediate member 150 may be at least one selected from the group consisting of polymethyl methacrylate, epoxy, polycarbonate, polyurethane, vinyl chloride, vinyl acetate, vinyl chloride, polyvinyl chloride, vinyl acetate, and polyvinyl acetate, but preferably, the resin may be formed of polymethyl methacrylate or polycarbonate which has a superior bonding force and can easily be broken when an external impact is applied at a predetermined force or greater.

The intermediate member 150 may be a hard material without elastic deformation, and preferably may be the same material as the resin 144. The reason for using the same or similar materials for the resin 144 and the intermediate member 150 is to make the intermediate member 150 bind easily to the abutment body 140. However, the material is not limited thereto, and may include anything that can easily bind with the resin 144.

The part of the intermediate member 150 on which the crown 120 binds may has a frusto-conical exterior shape, but it may also include other exterior shapes. The dental implant apparatus 100 according to an embodiment of the present invention with such a structure as described above has the following function.

First, after a clinical examination, an extraction hole is formed in the oral cavity of the human, and a fixture 110 is inserted into the hole. Here, the fixture 110 is inserted to a sufficient depth so that it does not fall off after the operation. Then, an abutment body 140 is placed on top of the fixture 110. Here, a step coverage 141 of the abutment body 140 is interlocked with a step 112 of the fixture 110. Then, a screw 160 is inserted through a second screw hole 142 of the abutment body 140, such that the screw 160 is fastened to a first screw hole 113 of the fixturei 10. Once the bond of the abutment body 140 and the fixture 110 is completed, a intermediate member 150 in which a resin is applied 144 in the interior is attached to the top portion of the abutment body 140. Then, an appropriate amount of cement 121 is pasted inside the crown 120, and the crown 120 is bound to the intermediate member 150. When the cement 121 leaks out while the crown 150 is placed over the intermediate member 150, the leaked cement 121 is removed to finish the operation. The dental implant apparatus according to an embodiment of the present invention as described above has the following effects.

First, according to an embodiment of the present invention, the abutment body and the fixture are firmly bound by the screw, and the crown and the intermediate member are also firmly bound by the cement. However, the intermediate member and the abutment body are bound together by a predetermined adhesive force of a resin.

After the treatment, in the case where the subject of operation chews on hard food or applies a large impact to the crown, the impact transferred through the crown passes through the intermediate member to the resin. The resin is broken by the impact transferred to the resin, and the intermediate member and the abutment body are separated as shown in FIG. 6. Therefore, the impact exerted on the crown is not transferred to the fixture directly through the abutment. When the crown and the intermediate member are separated from the abutment body as such, the subject of operation can revisit the dentist to receive a simple treatment to reattach the crown and the intermediate member with a resin. Of course, the resin is not broken by an impact up to a certain degree, that is, an impact small enough to not greatly affect the fixture, and transfers the impact received from the crown to the fixture. However, such a small impact can be sufficiently borne by the fixture, and therefore does not affect the fastening of the fixture to the jawbone.

Meanwhile, the amount of resin used to bind the intermediate member and the abutment body is adjusted appropriately by calculating beforehand the degree of impact that the fixture can bear.

In contrast, if the impact is directly transferred to the fixture as conventionally occurs, the position of the fixture that is not yet completely healed may shift, and the fixture needs to be re-implanted in the jawbone. The process of re-implanting the fixture is not only very tedious, but is also extremely inconvenient for the patient because it requires a relatively serious operation.

In addition, the dental implant apparatus according to an embodiment of the present invention has the intermediate member and the abutment body having a frusto-conical exterior shape, making it convenient to install the crown. Generally, there are cases where the fixture implanted in the jawbone is not formed in an exactly perpendicular direction, but is slanted to a small degree according to the form of the jaw or the bone tissue, as shown in FIG. 4. In addition, the abutment that is screwed on top of the fixture is also installed at an angle to the vertical line. However, even if the fixture and the abutment are implanted at an angle to the vertical line, the crown should be disposed at a perpendicular angle within the oral cavity. If the crown is bound on top of the abutment perpendicularly, the left part of the cutting line S in the abutment is blocked by the crown, thus the crown cannot be installed on the abutment. In order to solve this problem, a part of the abutment (the left part of the cutting line S of the abutment body in FIG. 3) can be removed using a milling cutter or the like so as to install the crown on the abutment. However, performing this cutting operation during the implant operation is not only tedious, but may also increase the operation time.

In contrast, an embodiment of the present invention includes an abutment body and the intermediate member having a frusto-conical exterior shape as shown in FIG. 8, and thus the crown can be installed without requiring a separate cutting procedure. To this end, the dental clinic may prepare abutment bodies with different slope angles (the enclosed angle between the center axis and the exterior surface of the abutment body (α)), and having prepared the intermediate members corresponding to the abutment body, appropriate parts can be selected to fit each subject of operation.

This substantially reduces the overall operation time, and non-skilled personnel can easily perform the implant operation because it does not require a milling procedure during operation.

The dental implant apparatus according to an embodiment of the present invention can also be modified as follows.

A hooking part 151 and a hooking holder 145 may also be prepared on the intermediate member 150 and the abutment body 140 of the embodiment previously described. As shown in FIG. 9, the hooking part 151 that protrudes inside the surface that contacts the abutment body may be prepared on the intermediate member 150.

In addition, a hooking holder 145 may be prepared on the abutment body 140 which prevents separation of the intermediate member 150 from the abutment body 140 when it is interlocked on the hooking part 151 of the intermediate member 150 while the intermediate member 150 is attached to the abutment body 140.

The intermediate member 150 and the abutment body 140 maintain a bond due to a bonding force between the hooking part 151 and the hooking folder 145, and a bonding force of the resin.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

1. A dental implant apparatus comprising: a fixture binding to a human jawbone to form an artificial dental root; a crown forming the exterior of an artificial tooth; and an abutment of which one side binds to the fixture and the other side binds to the crown, wherein the abutment comprises: an abutment body binding to the fixture; and a intermediate member disposed between the abutment body and the crown, in which the exterior of the intermediate member binds to the crown, and the interior of the intermediate member binds to the abutment body by a resin, such that in the case where an impact is transferred from outside to the resin, the resin breaks and the intermediate member separates from the abutment body.

2. The dental implant apparatus of claim 1 , wherein the resin is one of polymethyl methacrylate and polycarbonate.

3. The dental implant apparatus of claim 1 or 2, wherein the intermediate member is formed of a hard material without substantially elastic deformation.

4. The dental implant apparatus of claim 1 , wherein a part of the intermediate member binding to the crown comprises a frusto-conical exterior shape.

5. The dental implant apparatus of claims 1 or 4, wherein a part of the abutment body to which the intermediate member is attached comprises a frusto-conical exterior shape.

6. The dental implant apparatus of claim 1 , wherein a hooking part is provided on a surface of the intermediate member which contacts the abutment body, and wherein a hooking holder is provided to prevent the intermediate member from being separated from the abutment body by holding the flange of the intermediate member, while the intermediate member is attached to the abutment body.