DE202008018507U1 - Dental implant with a thread for screwing into a bone - Google Patents

Abstract

Dental implant for screwing into a bone, consisting of a base body and a thread formed with the main body, which tapers in the screwing towards a tip, wherein the base body over the longitudinal extent of the dental implant has different diameters and the thread has different outer diameter and thereby different sections are formed from the head of the dental implant to the tip, wherein - a portion (2.1) is provided, which is divided into a first subsection (2.1a) and in a further subsection (2.1b), - the second subsection (2.1b ) with a constant in this section (2.1b) cylindrical outer diameter of the base body (2) and constant cylindrical diameter of the outer diameter of the thread (4) is characterized in that - the subsequent to this subsection (2.1b) in the direction of the tip further subsection (2.1a), having a conical base body (2) leading to the tip in the form of a sheath H2 and a parabolic outer contour in the form of a sheath H1 of the thread (4), is formed such that from the tip to the end of the first subsection (FIG. 2.1b) the thread depth initially increases with a constant pitch and decreases within the further subsection (2.1a).

Description

Technical area

The present invention relates to a threaded dental implant adapted to be screwed into a bone. Preferably, it is used to be inserted into a jawbone.

definitions

The term "medical device" with reference to the invention described herein is to be understood to mean a device which comprises a base body which comprises at least one thread on its outer wall. The medical device is designed such that it is suitable for use in or on the human or animal body. In particular, the medical device described herein is an implant that consists of an artificial, either resorbable or non-resorbable material that is intended to remain permanently or at least for a prolonged period of time within the body. Preferably, the medical device is a dental implant. An alternative is also that the medical device is a screw intended for fastening a plate or for fixing bones.

State of the art

A dental implant is a device that is fixed by a suitable attachment to the bone. The implant usually consists of a base body which extends apically into the bone, wherein on the cervical side of the implant, a shaft is provided, on the one hand the function of receiving a prosthesis in the formation of a tooth, in particular crown or prosthesis, having. On the other hand, the shaft in its special design serves to insert the implant into the bone and fix it there.

The body is provided with facilities that provide for stable attachment within the bone care.

In order to fix such an implant, the bone is first exposed in the area to be applied and then provided to create a bore, such that a preferably cylindrical cavity with a smooth surface is formed. Then there are two possibilities:
On the one hand, it is intended to cut a thread in the bone, which corresponds to the thread of the implant. Another possibility is not to further process the surface of the bore, but to select an implant that has a cutting thread.

The useful life of a prosthesis based on such an implant is highly dependent on the so-called osteointegration. This is a process that is described by the growth of the bone tissue structure in direct apposition of the implant. Osteointegration is also strongly influenced by the so-called primary stability of the implant, such that the tighter the implant is fixed within the bore, the better the bone growth.

In order to achieve a reliable anchoring within the produced bore, implants are used with cutting threads. These are available in large numbers and design on the open market. Thus, it is known to use differently designed threads for such implants. Implants with conical threads and different conicities on the same implant are known. Some other implants have threads that are cylindrical. It is already known from known methods that good, long-lasting results are achieved when osteointegration between the bone and the implant can take place with a narrow profile and small thread pitches.

In the WO 9725933 A as well as the WO 9306786 A (RUSSO, GIANNI) 05.10.1992 implants are presented, which have threads that have a small conicity along the body. The flank base formed between the flanks of the thread is identical almost over the entire longitudinal extension of the base body.

In the WO 9725933 A is proposed, in particular in conjunction with a hard bone, that the body should also have an asymmetric cross-section. This has the advantage of reducing the friction between the thread and the bone so as not to damage the bone trabeculae within the bone, which are essential for osteointegration.

From the DE 695 6 562 T2 is an orthopedic interference screw known. It serves to pressure anchor a bone graft in a bore. The screw itself has a taper towards the tip, with the thread depth remaining constant at both the tip and the rest of the body.

The US 2005/0100861 teaches this knowledge of conicity and the constant thread depth - too in the area of the tip - to apply to a dental implant.

From the DE 91 04 027 a bone screw is known in which the main body thickened towards the screw head.

A pedicle screw is in the DE 41 06 876 A1 described. This is characterized by the fact that the base body and outer sheath laid on the thread crests of the pedicle screw are not parallel, so that different thread depths are present over the longitudinal extent of the pedicle screw.

Description of the invention

Technical problem

The problem with using cylindrical dental implants in cylindrical bores is that the threaded bore, which in most cases is created by a self-tapping tip of the implant, widened the cylindrical bore when the implant is screwed in. This occurs especially in the entry area of the bore (sometimes already by the drilling itself). This implies that there is little primary stability, especially in the cervical area. When conical implants are used, creating a conical hole usually causes the problem of heat build-up due to the cutting action and denting, which can lead to the destruction of the bone structure.

In itself, it is obvious to make the threads so that they are cylindrical and have a large thread profile with thin flanks. However, these thin threads have the disadvantage that the few threads lead to increased loads within the bore. In addition, due to the few threads no irregularities of the bone can be compensated.

Thus, the object is to provide an implant which serves to solve at least one of the problems mentioned.

Solution of the task

The solution of the problem is defined by claim 1.

Advantages of the invention

A substantial advantage of the implant according to the invention is that it can be guided into a cylindrical bore, so that the advantage lies in the production and gentle processing of the bone and at the same time the implant has a cutting thread, on the apical-facing side a few threads for cutting are formed, the rest are provided exclusively to achieve the primary strength.

The thread on the base body is designed such that it has the same pitch over the longitudinal extension of the base body. The slope is chosen so that sufficient osteointegration is achieved because it does not have a fine thread structure. As a result, a good enforcement of bone structures is possible.

In contrast to the prior art, the thread shown here has a cylindrical shape, although the main body shows a taper. This means that in the apical region of the implant, the flank depth is large, whereas it decreases in the cervical direction.

Advantageously, the flanks of the thread are designed such that the apically-facing flank is formed perpendicular to the longitudinal extent. This means that the flank surface is flat. This achieves a high primary strength.

In the cervical direction, the configuration of the flank surface remains the same, but the flank depth changes in such a way that it becomes smaller.

An advantageous embodiment provides that at the cervical end of the base body of the implant, a fine thread is provided with a smaller thread pitch compared to the other thread. It serves to also increase the primary strength. The fine thread additionally produces a toothing to the already processed bone, since precisely this area can no longer have any smooth surfaces by the attachment of the drill and / or the implant and possibly even in its dimensions is greater than the remaining part of the cylindrical bore.

The formation of the implant in the described embodiment also allows the area for receiving a prosthesis or cooperation with a tool for screwing in the implant to be made sufficiently large and larger in dimensions than the base body, since the forces to be transmitted are due to the strong forces Cutting action of the first apical indicative threads are sufficiently large.

Thus, the main advantage of the implant results from the fact that, for example, in soft bones, which is pre-drilled with a small diameter, immediately after insertion of the Implant engages the apical tip of the implant and due to the extremely fast tangential slope (formed by a sheath, which rests on the flank tips of the thread in contrast to the tangential pitch of the body) a spinning of the thread is prevented.

Already from the time at which the bone is widened to the core diameter of the diameter of the thread of the second section, this diameter remains identical over the longitudinal extension of the implant, so that viewed from the base body there is a cylindrical configuration. This avoids that no further bone compaction takes place in this area.

The special configuration of the second section of the implant provides for compensating for tolerances that arise in particular when drilling on the cervical side.

Therefore, the second portion of the implant is plug-shaped and larger in diameter than the rest of the part. In addition, it is provided that in this second section, although a thread is provided with the same pitch, as it is already known from the first section, but in duplicate (double thread, such that the distance between the one edge tip to the adjacent edge of the flank is halved) in order, in particular in this area, to achieve the desired high primary stability.

A particular embodiment of the invention therefore provides, over the entire longitudinal extension of the implant, to use the same pitch of the respective sections of the thread, but to differentiate into flank depth and edge spacing.

The implant according to the invention is not restricted to use in the dental field. Rather, it also forms the basis for a screw that is also used in the bone area and it is desired that sufficient stability or strength should be present.

Further advantageous embodiments will become apparent from the following description and the claims. This shows a representative of the inventive medical device and the thread of a dental implant having the thread according to the invention.

drawings

Show it:

1 a perspective view of the inventive implant;

2 a side view of the implant;

3 a section through the implant along a line III-III according to 2 ;

4 a section through the implant along a line IV-IV according to 2 ,

Description of an embodiment

The description of an embodiment relates to the representation in the 1 to 4 ,

This is an implant 1 shown, essentially a basic body 2 and a cervical shaft 3 includes. The shaft 3 is designed as a functional element (means) and serves on the one hand, with a corresponding tool, such as a screwdriver, cooperate to screw the implant into a bone. Furthermore, it serves for example to receive a prosthesis.

The main body 2 is in this illustrated embodiment in two sections, namely a first section 2.1 and another section 2.2 divided and threaded 4 Mistake. The first section is on the apical side of the implant 1 whereas the other section 2.2 on the cervical side of the body 2 Direction of the shaft 3 extends.

The main body 2 itself extends in the apical direction initially cylindrical, with this section extends conically from a defined point.

The thread 4 is defined by thread flanks 4.1 , the distance 6 from a thread flank 5 to the adjacent thread flank 5 as well as the flank depth 7 extending from a flank tip 8th to the flank bottom 9 measured. The thread 4 in the area of the first section 2.1 is arranged, has the same slope S1 over the entire area. A hull H1, which over the flank tips 8th of the first section 2.1 is laid, has a pointing to the apical side parabola.

Additionally, in the first section 2.1 recesses 10 provided, which have the property of the first threads of the thread 4.1 of the first section 2.1 take up removed material and transport it in the cervical direction.

The thread flank 5 is preferably designed such that its two flank surfaces, namely the first flank surface 12.1 and the other flank surface 12.2 are not symmetrical. The first flank surface 12.1 , which points to the apical side, is flat and preferably extends perpendicular to the longitudinal extent of the body 2 whereas the more flank surface 12.2 forms an angle α with the flank tip.

The second section 2.2 has another thread 4.2 on, in contrast to the thread 4.1 of the first section 2.1 has a lower slope S2. The longitudinal extent of this section 2.2 is compared to the first section 2.1 also much shorter. A special embodiment of the implant 1 shows that the slope S1 of the first section 2.1 the slope S2 of the second section 2.2 equivalent. Another preferred embodiment shown in the drawings shows that the further section 2.2 has a double thread. This is characterized by the fact that the distance between the flank tips 8th this further section 2.2 opposite the first section 2.1 is halved.

Functionality:

To the different function of the thread 4 , which is divided into its corresponding sections (first section 2.1 , second part 2.2 ), the implantation of an implant is explained below.

Depending on the bone in which the implant 1 is introduced, is pre-drilled with an appropriate diameter.

The implant according to the invention 1 is inserted with its apical tip in the direction of insertion E in the pre-drilled bore, to the point where further insertion is no longer possible. This is the time at which the first thread of the first section 2.1 attacks. The first paragraph 2.1 is divided into two subsections, namely a first subsection 2.1a and a second subsection 2.1b , The first subsection 2.1a is formed so that the thread 4 (in 3 through a hull H1, which over the flank tips 8th is shown) has a steeper compared tangential slope than the main body 2 , which is preferably conical in shape and in 3 is shown by a sheath H2 in cross section.

This particular embodiment now leads to the fact that immediately after insertion of the implant 1 into the hole the thread 4 apical begins to grip. By further screwing in is prevented due to this particular embodiment that when inserting the bone compaction generated by the screwing, a spinning of the implant 1 is prevented.

Will the implant 1 now further screwed, the implant reaches the point, namely the second subsection 2.1b , In this area, the bone becomes the core diameter of this threaded section 4.1 extended. Because of that, the main body 2 In these areas, its size is no longer greater, the bone compaction is then adjusted at a certain point, so that with the same thread 4 this alone achieves a higher primary stability.

By further screwing is now the second section 2.2 of the implant 1 reached. This area is designed such that it has a double thread 4.2 which also shows a slope S2, that in the first section 2.1 provided slope S1 corresponds. As a rule, this is exactly this area, because this one of the implant 1 has already been passed through, but also when drilling the desired diameter is designed by appropriate tilting further than necessary. Therefore, the implant is 1 in terms of its founding body 2 on the one hand designed larger in diameter to cover just these resulting machining tolerances and on the other to increase the primary stability. In addition, however, a double thread is provided with which also a high primary stability can be additionally achieved.

The implant according to the invention is characterized by a simple implantation in a cylindrical bore which can be implanted with a lower torque compared to the prior art. In addition, a high primary strength is given in comparison to the prior art. Conventional tools for making the bore and for implanting can be readily used. The design of the implant or of the medical device according to the invention combines all the advantages of implants and screws for screwing into bone, which have exclusively a conical or cylindrical basic body with the corresponding thread of the same flank depth.

The advantages of the cylindrical design are high safety, no damage to the bone, combined with the advantages of conical design (high bone density, high primary stability).

The invention is not limited to implants for the tooth area. Rather, there is the claim to the inventive thread, the medical devices, such as implants, screws or The same is arranged for screwing in bone.

LIST OF REFERENCE NUMBERS

1

 implant

2

 body

2.1

 first section

2.1a

 subsection

2.1b

 subsection

2.2

 another section

3

 shaft

4

 thread

4.1

 thread

4.2

 another thread

5

 thread flank

6

 distance

7

 edge depth

8th

 edge tip

9

 edge basic

10

 recess

12.1

 first flank surface

12.2

 further flank surface

S1

 pitch

S2

 pitch

H1

 shell

H2

 shell

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 9725933 A [0008, 0009]
• WO 9306786 A [0008]
• DE 6956562 T2 [0010]
• US 2005/0100861 [0011]
• DE 9104027 [0012]
• DE 4106876 A1 [0013]

Claims (5)

Dental implant for screwing into a bone, consisting of a base body and a thread formed with the main body, which tapers in the screwing towards a tip, wherein the base body over the longitudinal extent of the dental implant has different diameters and the thread has different outer diameter and thereby different sections formed from the head of the dental implant to the tip, wherein - a section ( 2.1 ), which is included in a first subsection ( 2.1a ) and in another subsection ( 2.1b ), - the second subsection ( 2.1b ) with one in this section ( 2.1b ) constant cylindrical outer diameter of the main body ( 2 ) and constant cylindrical diameter of the outer diameter of the thread ( 4 ) is characterized in that - the subsection ( 2.1b ) in the direction of the tip further subsection ( 2.1a ), a leading to the tip conical body ( 2 ) in the formation of a sheath H2 and a parabolic outer contour in the formation of a sheath H1 of the thread ( 4 ) is formed such that from the tip to the end of the first subsection ( 2.1b ) the thread depth initially increases with a constant pitch and within the further subsection ( 2.1a ) decreases. Dental implant according to claim 1, characterized in that the cylindrical threaded portion ( 2.1b ) and the sealing threaded portion ( 2.2 ) have a same outer cylindrical shape, wherein the respective flank depth ( 7 ) of the thread ( 4.2 ) of the sealing threaded portion ( 2.2 ) to the transition of the shaft ( 3 ) decreases linearly. Dental implant according to claim 2, characterized in that the threads ( 4.1 ; 4.2 ) the threaded portion ( 2.1a ; 2.1b ; 2.2 ) have equal slopes (S1, S2). Dental implant according to claim 2 or 3, characterized in that the thread ( 4.2 ) of the sealing threaded portion ( 2.2 ) is designed as a double thread. Dental implant according to one of claims 1 to 4, characterized in that the threaded sections ( 2.1a ; 2.1b ) and / or the threaded portion ( 2.2 ) a recess ( 10 ), which in the axial direction of the screw body ( 2 ) runs.

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