The invention relates to a tooth implant with an implant corpus, which forms in its longitudinal axis consecutively at least one enossel area that can be anchored in a bone, an emergence area through a soft tissue and a corona area with retention pins.
Tooth implants are known in the art, for example from document EP 0 388 576 B1 or EP 0 668 751 B1. A tooth implant must generally be able to be anchored optimally in the jaw of the patient while withstanding a high degree of mechanical stress, with sufficient anchoring stability being achieved before complete healing. Furthermore, it is necessary to manufacture such implants from a biocompatible or a tissue-compatible material. Suitable materials for this purpose are, for example, titanium or titanium alloys, or also ceramics, such as in particular zirconium oxide ceramic. However, the use of several different materials is also possible; for example in the manner that a core area of the implant is made of titanium or a titanium alloy and the outer surface of the implant or implant corpus is made of a layer of ceramic, for example zirconium oxide. Implants made of multiple components are also conceivable.
Furthermore, it is necessary to design the tooth implant so that it can be inserted in place of a missing tooth between two existing teeth in the jaw of a patient.
The object of the invention is to present a tooth implant that can be fastened in the jaw of a patient with a minimum amount of time and effort and in such a manner that it possesses the high degree of anchoring stability required, especially after healing.
This object is achieved by an implant with an implant corpus which forms in its longitudinal axis consecutively: at least one enossal area that can be anchored in a bone; an emergence area through a soft tissue; and a coronal area with retention pins. The enossal area is composed of at least three threaded sub-areas consecutively adjoining the longitudinal axis. The core of the implant corpus in both the apical sub-area and in the coronal sub-area has a cross-section that increases in at least one cross-section axis to the coronal area and has an essentially constant cross-section in the alveolar sub-area inbetween, and that the free ends or points of the threads are located on a common enveloping surface enclosing the longitudinal axis. The surface has its largest distance from the core of the implant corpus at the transition between coronal sub-area and the alveolar sub-area and the apical sub area and/or at the alveolar sub-area. The enossal area of the implant corpus has on its outer surface threads located on an envelope curve enclosing the longitudinal axis. The envelope curve in the apical sub-area and the coronal sub-area has a cross-section that increases at least in an axis direction radially to the longitudinal axis in the direction of the coronal area and has an essentially constant cross-section in the alveolar sub-area inbetween.
The invention is described below in more detail based on exemplary embodiments with reference to the drawings, in which:
The tooth implant generally designated 1 in the drawings is manufactured in the depicted embodiment as a piece of at least one suitable material for tooth implants, e.g. of titanium and/or zirconium oxide, essentially with an elongated area 2 to be anchored in the jaw of a patient, a middle area or emergence area 3 adjoining the implant 1, with which the implant 1 emerges through the soft tissue after implanting and healing, and a coronal area 4, which is formed essentially by a retention pin 5, on which then for example a cap made of a preparable, difficult to prepare or non-preparable ceramic or made of other suitable metal and indicated in
In the depicted embodiment, the enossal area 2 consists of three sub-areas, which adjoin in longitudinal direction L and each of which is provided with outer threads, namely of the apical sub-area 2.1 furthest away from the coronal area 4, of an adjoining alveolar sub-area 2.2 and of an adjoining coronal sub-area 2.3, which then adjoins the emergence area 3, which increases in cross-section in the form of a truncated cone in the direction toward the retention pin.
In this enossal area 2 the core of the implant is formed so that said core has essentially the form of a truncated cone in sub-section 2.1 with a circular cross-section that enlarges toward the retention pin 5 and is rounded on its free end at 7. The taper angle α, i.e. the angle formed by a surface line extending parallel to the longitudinal axis L, is approximately 2 to 5° in the depicted embodiment.
In the sub-area adjoining the sub-area 2.1, the core of the implant has a cylindrical or essentially cylindrical form in relation to the longitudinal axis L, i.e. an essentially constant cross-section, which in the depicted embodiment is circular.
In the sub-area 2.3 adjoining the sub-area 2.2, the core of the implant again has a slightly truncated form, namely such that the core diameter increases in the direction of the retention pin 5, and the taper angle β, i.e. the angle formed by an imaginary surface line extending parallel to the longitudinal axis L, is smaller in the depicted embodiment than the taper angle of the emergence area 3 that increases toward the retention pin 5 in the manner of a truncated cone and is approximately on the order of the angle α, i.e. β is for example between 2 and 5°.
The core or core diameter are the cross-section area on which the base surface of the threads is located in the sub-areas 2.1, 2.2 and 2.3.
In
The described embodiment of the implant and of the enossal area 2 features the advantage for example that the respective truncated cone design of the core in the sub-areas 2.1 and 2.3 achieves a secure anchoring of the implant corpus in the bone both at the lower, apical area and at the transition between the bone and the soft tissue, and that the larger depth of the threads in the sub-area 2.2 and also at the transition to sub-area 2.3 in the bone tissue and with a sufficient distance from the transition between the bone and soft tissue achieves especially effective anchoring of the implant, thus ensuring the supporting area of the anchoring of the implant in the bone.
Reducing the threads in the sub-areas 2.1 and 2.3 prevents especially mechanical stress peaks in deeper layers of the bone and in the area of the periosteum when inserting or screwing the implant 1 into a hole prepared in the jaw bone.
Also the depth of the threads in the sub-area 2.1 is for example between 0.3 and 0.8 mm and in the sub-area 2.3 at the transition to the emergence area 3 approximately between 0.3 and 0.4 mm. The greatest depth of the threads at the transition between the sub-areas 2.1-2.2 and 2.2-2.3 and in the sub-area 2.2 is for example between 0.3 and 2.5 mm.
In the depicted embodiment, the implant corpus is roughened on the outer surface at least in the enossal area 2, but preferably also in the emergence area 3, namely in the area of the threads both at the points and at the base of the threads. The surface roughening is produced for example by mechanical processing and/or etching and/or coating and/or suitable nanotechnologies.
In general it is also possible to design the threads differently in the individual sub-areas 2.1, 2.2 and 2.3 with respect to the cross-section form of the threads and/or the thread pitch.
As indicated in
8.2 designates a notch in the thread, i.e. a recess extending in the longitudinal direction of the tooth implant, which facilitates the insertion of the tooth implant into the bone tissue with its threads.
As shown in particular in
In the depicted embodiment, the threads at the transition of the sub-area 2.3 and of the emergence area 3 or at said emergence area are designed following the garland-shaped course of the groove 9, i.e. the threads are incomplete there, so that threads are provided only where the garland-shaped course of the groove 9 has the smaller distance from the reference plane BE or lies in the reference plane and is increasingly omitted where the distance between the garland-shaped course of the groove 9 and the reference plane is larger.
The increased depth of the threads at the transition between the sub-areas 2.2 and 2.3 and also in the area 2.2 increases the total surface of the flanks of the threads, resulting in the increased anchoring of the implant in the bone tissue in this supporting area of the implant.
The differing depth of the threads is achieved with a constant pitch for example through different flank angles of the threads and/or through a different width of the base of the thread. However, both of these measures can also be combined.
While the core of the enossal area 2 of the implant corpus in relation to the longitudinal axis L is rotationally symmetric in the depicted embodiment, the emergence area 3 has an oval cross section, the cross section dimension 13 of which is smaller than the cross section dimension 14. The cross section dimension 13 corresponds to the buccal/approximal axis and the cross section dimension 14 corresponds to the axis on which also the areas of the garland-shaped course of the groove 9 lie in the reference plane BE.
In order to optimally cover a wide variety of applications, the implant 1 is available in different models and sizes, in particular also with different diameters especially in the enossal area 2 and in the emergence area 3, where the cross section in the emergence area 3 in the depicted embodiment is not rotationally symmetric to the longitudinal axis L, but slightly oval, corresponding to
Furthermore, the garland-shaped course of the groove 9 is different depending on the use of the implant. The following table shows this course through the distance x from the reference plane BE for different implants:
The shape of the retention pin is preferably dependant on the respective use or application of the implant 1. In any case, the retention pin 5 has a cross section that deviates from a circular shape, so that a suitable tool can grip said retention pin for inserting the implant.
A possible cross sectional form of the emergence area is depicted in
The retention pin has for example a stylized shape adapted to the shape of the tooth to be replaced, as shown again in
In order to enable a positive connection with the respective tool for inserting the implant, the cross section of the respective retention pin is designed so that it deviates from a circular shape, i.e. it is oval or approximately oval.
For an implant 1 that is intended for the front teeth, the retention pin has a flame-shaped design in the buccal/approximal view adapted to the shape of these teeth in a cross section plane, i.e. corresponding to the line 5.1 so that the retention pin 5 is tapered to a point at its free end in this cross section view, namely so that the outer contour of the retention pin is formed on the inner, lingual side by two slanted surfaces, both of which form an angle smaller than 90° with the reference plane BE, said angle opening toward the longitudinal axis L, where the respective angle of the surface 15 following the emergence area 3 is somewhat larger than the corresponding angle of the adjacent surface 16 transitioning into the tip 17. The tip 17 lies in the area of the longitudinal axis L. On the other side, the contour of the retention pin 5 is formed by a slanted surface 18 that is slightly convex on the outer side. In a cross section plane perpendicular to the buccal/approximal plane the retention pin 5 for the front teeth has an essentially trapezoidal cross section. Also for use in premolars and molars the retention pin has the trapezoidal cross section in both cross section planes.
The described shape of the retention pin for the implant for the front teeth makes it possible to design the cap fastened with the retention pin 5 corresponding to the anatomical form while maintaining sufficient preparability.
Generally it is also possible to flatten the retention pin on its free end, as indicated by line 17.1.
It is also possible to form the retention pin 5 corresponding to the anatomical form of the natural teeth, where said retention pin then for example has the dimensions listed in the following tables.
In an embodiment of the invention, the starting point for the form of the retention pin 5 is the natural tooth form. Compared with the contour of the natural tooth form, the retention pins are reduced in size by a certain dimension, which is for example between 0.1 and 5.5 mm, although this dimension does not exceed the usual material thickness of the retention pin 5 plus the shell of a single crown, bridge element, telescope, etc. Details are shown in the following table:
Further examples for the shape of the retention pin adapted more nearly to the anatomical tooth form are described in
A1=diameter of the retention pin at the top or tip in labial view;
A2=diameter of the retention pin at the height of the start of the Tuberculum dentis in side view;
B=diameter of the retention pin in the middle of the pin for an implant for front teeth and premolars; for an implant for molars, at the transition of the cusps to the body/corpus of the pin;
C=diameter of the retention pin at the stage or in the area of the base;
D=diameter of the retention pin at the largest circumference at the transition to the emergence area 3;
E0=height of the retention pin measured between the lowest point of the garland-shaped groove 9 and top side or tip of the retention pin in labial or buccal, lingual and palatinal view for an implant for front teeth and premolars;
F=height of the retention pin measured between the highest point of the garland-shaped groove 9 to the top of the retention pin;
G1=cusp distance from buccal-palatinal/lingual view for an implant for molars;
G2=cusp distance from mesial-distal view for an implant for premolars and molars;
H1=depth of the saddle formed by the cusps on the top of the retention pin for an implant for premolars;
E1=height of the buccal cusps from side view;
E2=height of the palatinal cusps from side view;
E3=height of the retention pin measured between the transition to the emergence area 3 and the mesio-buccal cusp;
E4=height measured between the transition to the emergence area 3 and the disto-buccal cusp
E7=height of the retention pin measured between the transition to the emergence area 3 and the mesio-palatinal/lingual cusp;
E8=height of the retention pin measured between the transition to the emergence area 3 and the disto-palatinal/lingual cusp;
E5=height measured between the transition to the emergence area 3 and the mesio-buccal cusp;
E6=height measured between the transition to the emergence area 3 and the mesio-palatinal/lingual cusp;
E9=height measured between the transition to the emergence area 3 and the disto-buccal cusp
E10=height measured between the transition to the emergence area 3 and the disto-palatinal/lingual cusp
H2=depth of the saddle in buccal view or palatinal/lingual view
H3=depth of the saddle in side view from mesial and distal view
I=height of start of Tuberculum dentis
L=height of end of Tuberculum dentis
All values listed in Tables 4 through 15 are in millimeters. Deviations from the values listed in Tables 4-15 on the order of 0 to 3 millimeters are possible in this embodiment.
The enossal area 2 in the depicted embodiment consists in this embodiment also of three sub-areas, which adjoin in longitudinal direction L, each of which has essentially the same axial length L and each of which is provided with outer threads, namely of the apical sub-area 2.1 furthest away from the coronal area 4, of an adjoining alveolar sub-area 2.2 and of an adjoining coronal sub-area 2.3, which then also in this embodiment adjoins emergence area 3, which has an increasing diameter in the form of a truncated cone in the direction of the retention pin. The threads, as shown in
Notches are again designated by 20.4.
A special feature of the implant 1a is the fact that not the core of the enossal area 2, but rather the envelope, designated 20 in
The pointed, i.e. blade-like design of the profile of the threads, prevents tensions when screwing the implant 1a into the jaw.
The free ends of the threads and also the roughened surface are both located on a conical surface concentrically enclosing the longitudinal axis of the implant, as indicated by the line 24. The bottom of the threaded area 21 is likewise located on an imaginary conical surface with an increasing diameter in the direction of the retention pin 5, as indicated by the line 25; however, the conical angle of the conical surface 25 is greater than the conical angle of the conical surface 24, so that the depth of the threads decreases in the direction of the retention pin 5.
As indicated especially in
Both the implant 1 and the implant 1a can be coated on the outer surface, namely with a tooth-colored coating corresponding to the tooth colors A2-A4, for example with a corresponding coating or layer made of zirconium oxide. It is also possible to manufacture the respective implant 1 or 1a completely from this material corresponding to the tooth colors A2-D4, e.g. from zirconium oxide.
It was assumed in the above description that the enossal area 2 of the implant 1 or 1a has a rotationally symmetrical design in relation to the longitudinal axis L, i.e. a circular or conical cross section. It is generally also possible to design this area so that it is oval or square.
With increasing distance from the end 7, for example in the area designated 20.1 in
The depth of the surface roughening is, for example, between 0.18 and 0.38 mm. In the embodiment depicted in
A distinctive feature of this embodiment of the invention is for example that the threads 26 have a consistent pitch throughout, i.e. the distance between two adjacent threads over the entire length of the implant is constant or essentially constant, and that the threaded area 26 starting at a certain distance from the end 7, for example starting with the area 20.2 in
A roughness profile then connects to the threads 26 at the upper end of the emergence area, with a roughness between 0.05 and 0.38 μm for supporting the soft tissue.
The invention was described above based on exemplary embodiments. It goes without saying that numerous modifications or variations are possible without abandoning the underlying inventive idea upon which the invention is based.
It was assumed above that the tooth implant is designed as one piece; however, it can also have a multi-part design, e.g. a two-part design.
It is possible, for example, that the threads and/or the roughened area has a wave-shaped course with a decreasing depth toward the coronal end.
Number | Date | Country | Kind |
---|---|---|---|
10 2004 027 543.2 | Jun 2004 | DE | national |
10 2004 061 792.9 | Jun 2004 | DE | national |
PCT/DE2005/000992 | Jun 2005 | DE | national |
This application is a divisional of U.S. patent application Ser. No. 11/628,451, filed Dec. 14, 2006.
Number | Date | Country | |
---|---|---|---|
Parent | 11628451 | Dec 2006 | US |
Child | 13005776 | US |