WO2002045613A1

WO2002045613A1 - Implant which can be applied in a recess in bone tissue, and method for such an implant

Info

Publication number: WO2002045613A1
Application number: PCT/SE2001/002626
Authority: WO
Inventors: Dan Lundgren
Original assignee: Nobel Biocare Ab (Publ)
Priority date: 2000-12-04
Filing date: 2001-11-28
Publication date: 2002-06-13
Also published as: SE518682C2; SE0004449L; SE0004449D0; AU2002224301A1

Abstract

An implant is arranged in a recess in bone. The imlant is intended to constitute an attachment or support for a prosthetic structure via one or more parts extending through the periosteum/mucosa of the bone. The portion or portions forming the attachment or support are arranged to penetrate with a low degree of penetration into the recess or recesses and with substantially their total area in the direction of extension. In the applied position of the attachment or support in the recess or recesses, the side surfaces of the portion or portions, together with parts of or all of said total area in the direction of extension, can be placed opposite and cooperate substantially only with cortical and/or subcortical layers in the bone.

Description

Implant which can be applied in a recess in bone tissue, and method for such an implant.

The present invention relates to an implant which can be set in a recess (bore, hole) in bone tissue and is intended to constitute an attachment or support for a dental or other body structure via one or more parts extending through the periosteum and mucosal covering of the bone. The invention also relates to a method for establishing an implant in bone where holes have been formed in the bone and an implant is then applied in the recess or recesses. More specifically, the invention concerns an intraosseous implant which in one embodiment can be anchored at several points . The implant has a part which penetrates through the mucosal covering or skin of the bone and attaches to a prosthetic structure or other arrangement which requires bone retention. Said part is in principle a spacer element.

The principles/arrangements/methods specified in connection with the invention can be used generally for structures anchored in bone. An advantageous area of application in this case is in dental structures. The fitting of implants is already well known and there are a great many different designs of implants and methods for anchoring the implants in the human jaw bone, for example. It is also already known to use so-called juxta-osseous dental implants which can have a spindlelike base with force-absorbing and more or less radially extending projections which have holes for retention screws which are secured in the cortical compact bone. In this respect reference can be made inter alia to the US patent 5,052,930. This patent proposes that the implant is designed so that it can be adapted individually to the upper bone surface on which the implant is applied. The bone surface is in most cases not plane, but either convex or concave, and can alternatively have a combination of these contours.

A fairly general problem when providing treatment with implants is that it should be possible to avoid adapting the implant to the individual at the time of application on the patient. One disadvantage of the implant described in said US patent specification is that it is designed in such a way that it has to be adapted individually to the underlying bone surface. In this connection it is also desirable to have a wide freedom of choice as regards the placing of the implant in the situation in question. The implant must also be of the type with which one can work with a low level of risk of inconveniencing the patient. In this connection, it is therefore desirable to use methods and arrangements in which the actual implantation work is carried out on the outer surface of the bone. It is crucially important to avoid going into areas of the bone which are rich in nerves.^" The implant and the associated method must also allow the dental situation in question to be planned and tackled in the minimum amount of time. In this connection, it is important to use standardized components to the greatest possible extent and for the range from which the dentist will choose components for the particular situation to be as small as possible. The components involved must also be made of tissue-compatible material, for example titanium.

It is an object of the present invention to make available an implant and a method which in conjunction with the implant solves all or some of the problems mentioned above. The invention is based__ on the recognition that the implant must be able to be held securely in the cortical compact bone and its nearest underlying layer, which is made possible by the fact that the implant is anchored in suitably bored or reamed recesses in the compact bone and underlying bone. According to the invention, this can be done, in a standardized manner and thus, for example, a projection or circular base portion of the implant used in one illustrative embodiment does not have to be 5 individually modified for adaptation to the bone contour. The positioning of the implant in bored recesses also means that the implant projections and base portions used in certain embodiments can be covered by transplanted bone or, as an alternative, 10 spontaneously overgrowing bone or bone substitute material, which reduces/eliminates the risk of this part of the implant perforating the mucosa covering the actual bone area.

15 In this type of implant it is also important to be able to reduce _the_ time needed for _the implant to become ..--incorporated- in. the-jaw bone.. —-.— — ------.--___

It is also already known to anchor intraosseous

20 implants in recessing grooves in the jaw bone. Said implants consist of so-called blade implants or disk implants. The known implants of this type and the methods which are used in conjunction with them mean that the implants in question are entirely dependent on

25 being anchored deeply and intraosseously in the same way as intraosseous cylindrical or screw-shaped implants. It is thus still not possible to solve the

- -- -abov-e—problems --using-thi-s -t-y-pe-~of implant. - - .

30 That which can principally be regarded as characterizing an implant of the type mentioned in the introduction is that the portion or portions forming the attachment or support are arranged to penetrate with__a low _degree of__ penetration into the recess or

35 recesses in question and with substantially their total area in the direction of extension, i.e. parallel to the bone surface, and that, in the applied position of the attachment or support in the recess or recesses, the side surfaces of the portion or portions and at least parts of said total area in the direction of extension can be placed opposite and cooperate substantially only with cortical and/or subcortical layers (immediately under the cortical bone) in the jaw bone.

In one embodiment of the implant according to the invention, the implant consists of a perforated plate with a centrally located spacer for attachment to the prosthetic structure. The plate is thus recessed in the cortical bone to a level with the subcortical layer and is covered by drilled-off bone, possibly in combination with bone substitute material. Screwing to the cortical bone with miniature screws may be considered in embodiments of the invention.

-In a further .embodiment, the implant consists of a straight or T-shaped bar. Alternatively, the bar can be designed in a cross shape. In a further alternative, the bar is replaced by a tube of corresponding shape. The implant is recessed in the bone by means of reaming or drilling. Said bar can be perforated and can be provided with miniature screws for active anchoring in the compact bone. The bar can also advantageously be covered by autologous graft bone and/or bone substitute.

•I-n--a -further- -embodiment, use is- made of a multi-point implant which in principle consists of a number of separate component implants, for example three, having a small diameter and penetrating through the mucosa, optionally via a respective joining piece. The three component implants are intended to be held securely in the cortical and subcortical part of the bone in a preferably standardized manner so that a centrally located supramucosal and standardized component for a bridge/prosthesis connection can be secured to the implants immediately after these have been fitted. Further embodiments of the invention are set out in the attached subclaims relating to the implant in question.

That which can principally be regarded as characterizing a method according to the invention is that the implant is designed with an attachment or support for the human body structure and with a part intended to extend through the periosteum of the bone to cooperate with the structure. Further features are that the attachment or support is designed with a portion or portions of low height which give a low degree of penetration in the recess or recesses and with a substantial total area in the direction of extension, and that the portion or portions are designed with at least parts of side surfaces which, upon said application in the recess or recesses, together with said total area in the direction of extension, are placed opposite substantially only cortical and/or subcortical layers in the jaw bone. It is additionally possible to use edges, flanges, etc., for press-fitting.

Embodiments of the method are set out in the subclaims concerning said main features .

The features proposed above afford a series of advantages and thus result in a combined securing to the cortical bone and to the nearest underlying subcortical bone. Thus, for example, there is no longer -any risk of the mucosa or periosteum being perforated by the underlying implant. Considerable advantages are also afforded from the patient' s point of view because it is possible to keep the construction work to the outside of the bone without needing to go down into sensitive parts in the bone. Implants of relatively technically simple structure can be used, and economically advantageous methods can be introduced. The range can be considerably limited and made up of technically simple and thus economically advantageously produced components. The planning of the dental, work can be made much easier and the new implants and the new method also permit great freedom of choice for positioning the implants in relation to the jaw bone. The implants do not therefore need to be applied to the top of the jaw bone and instead can be sited on the adjacent inclined side surfaces.

By means of the invention it is possible also to use principles which are known per se for flap formation and, for example, trepan drilling, final reaming, and short incorporation times.

DESCRIPTION OF. THE..FIGURES

Presently proposed embodiments of an implant and a method-----in --eonj-unct-ion with such an implant will be described below with reference to the attached drawings, in which

Figure 3 shows. £ diagrammatic perspective view, obliquely from above, of the application of an implant of a first embodiment in a jaw bone,

Figure 2 shows a diagrammatic vertical section of a second embodiment of an implant,

Figur — 3 - shows - a perspective view, obliquely • from above, of an implant similar to that in Figure 1, but with a wheel-shaped base plate,

Figure 4 shows a perspective view, obliquely from above, of a third embodiment of an implant,

Figure 5 shows, in a horizontal view, different types of further embodiments of implants arranged in a diagrammatically indicated jaw bone,

Figure 6 shows, in vertical section, a further embodiment of an implant in a jaw bone,

Figure 7 shows, in vertical section, an embodiment of an implant in a jaw bone differing from the above embodiments,

Figure 8 shows, in horizontal view and on an enlarged scale, an embodiment of an implant seen from Figure 5,

Figure 9 shows, in vertical section, an embodiment, differing from the embodiments in Figures 1-8, of an implant applied in a reamed hole or bored hole in a jaw bone, and

Figures 10-15 show,- -in -different views and sections, different structures and uses of the implants.

In Figure 1, the jaw bone is symbolized by 1. The jaw bone has a cortical layer la which at its inner parts merges into the subcortical layer lb of the trabecular bone. The jaw bone's actuaJ trabecular layer iε indicated by lc. In accordance with the present invention, at least the cortical layer la is provided with a reamed hole or bored hole 2 which in the present illustrative embodiment is circular. The reamed hole or bored hole 2 has a depth H of only 2-5 mm. Arranged in the recess 2 there is an implant 3 which in the embodiment shown has the shape of a circular -disk. The implant is designed with a central attachment or support part 3a which is intended to extend through the cortical (compact) bone la shown in Figure 1 and connected to the dental structure via a threaded hole 3a' . The implant can also be securely screwed into the cortical and subcortical layers la, lb by means of peripherally applied screws 5, 6, 7 which should be uniformly distributed about the periphery of the implant. The disk-shaped implant is also provided with a number of vertical through-holes 8 in which new bone can form after the implant has been applied in the recess. The base plate of the implant has a thickness h which is less than the depth H of the recess, for example 1-4 mm. The implant in this way comes to have a very low degree of penetration in the recess H and in the applied state in the recess is located at a marked distance A above a nerve branch Id. The implant has a diameter D which can assume values in the range of 6-12 mm, preferably ca. 10 mm. The underside 3b of the implant is thus designed with a large area in its direction of extension, which area can assume values of between about 50-100 mm². In accordance with the invention, a recess 2 is first reamed out in the bone, after which the implant is applied in the recess by press-fitting against the walls of the recess. The implant can also be securely screwed into the underlying _.bone by _ means of said screws in holes

-intended for this purpose in the implant. The implant thereafter becomes incorporated in the bone material, and bone + periosteum + mucosa can grow over the implant. When arranging the dental structure, for example prosthesis (not shown in Figure 1), on the implant via the attachment part 3a, holes are made in the mucosa in a manner known per se. The implant 'thus comes to take up a position in the recess which is already stable immediately after fitting. The attachment part 3a can constitute an attachment or support for the dental structure in question. In connection -with ■ the - application of the- -implant in the recess, the implant can be covered with removed bone possibly in combination with bone substitute material, i.e. autologous graft bone and/or bone substitute.

Figure 2 is intended to show an embodiment of the implant differing from the embodiment according to Figure 1. In this case the attachment or support part 3a also comprises a centrally placed recess 3a' in which a screw 11 has been applied temporarily during incorporation of the implant. This temporarily applied screw can then be replaced by a spacer element for joining to the dental structure. Implant, spacer element, screws etc. are made of tissue-compatible material, for example titanium. The implant 3 is also in this case provided with vertical holes 8 for incorporation of bone in the applied position of the implant. In addition, screw holes extending from the top surface 3c of the implant can be provided for vertically applied screws. In the present case the implant is designed with a downwardly turned edge 3e which can extend around the circumference of the implant, or alternatively round only parts of the periphery. Alternatively or in addition to this, the implant can be secured in the cortical and/or subcortical jaw bone using screws which are arranged in screw holes 3d' in -said -downwardly turned- edge or said downwardly turned portions. Also in the example according to Figure 2, the implant can be regarded as having a low degree of recessing in the .cortical and/or subcortical jaw bone. The implant in principle follows the^" contours of the cortical and subcortical layers in the cross section of the jaw bone according to Figure 2. The depth of recessing H' can be kept small in accordance with the invention and the implant portions in question have a height h' which is markedly less than the depth H' in accordance with the above. In this case, therefore, reaming or boring of a recess for the implant is carried out principally in the cortical and subcortical- layers, .after which the implant is applied in the recess by press-fitting, possibly together with securing screws. During incorporation, the screw 11 assumes its position (shown in Figure 2) in the internal thread 3a' . After incorporation, the mucosa 4 and bone material are opened up and the screw 11 can be removed, and a spacer element can be threaded into the hole 3a' , after which the dental structure can be applied.

Figure 3 shows a perspective view, obliquely from above, of a similar implant to the one in Figure 1, but with bars 12 extending radially outward from a central attachment or support part 3a, and with openings 8 between them, so that a wheel-shaped base plate is formed. The figure also shows a downwardly turned edge 3e which extends round the periphery and which in the present example can be complemented by radially extending through-holes (not shown) in the downwardly turned edge 3e for ingrowth of newly formed bone material. This design gives the implant marked torsional rigidity and retention in the jaw bone.

In accordance with Figures 4 and 5 it is possible to arrange, in the bone portion 1, implants which have designs -.differing slightly from those described above. In Figure 4, an implant -which is -rectangular or oval- shaped in horizontal section has been indicated by 3' . The -implant in question- has an attachment or support part 3a' ' ' arranged in its central parts 3a' ' . At the outer parts 3a'''' and 3a''''' of the implant there are securing arrangements with screws 6' and 7', respectively, in accordance with the above. In this case too, the implant has a low degree of recessing in the cortical layer la and the securing screws -are screwed mainly into this layer. In this case too, the implant is provided with vertical holes 8' for ingrowth of newly formed bone. In order to withstand any bending forces, the implant has been designed to be rigid

- aga-inst- torsion, as—has been indicated- by the cross section d in the figure.

Figure 5 shows, in horizontal view, three different examples of embodiments of the implant in accordance with Figure 4. The different embodiments have been indicated by 3' ' , 3''' and 3' ' ' ' . The design according to 3' ' is substantially rectangular in this horizontal section. The design 3''' has an oval-shaped horizontal section. The design 3'''' has a design with four wings which extend from a central part. Two of the wings are provided with securing screws for securing to the cortical and/or subcortical layers lb of the jaw bone. The implants according to Figure 5 have corresponding securing arrangements and hole arrangements for incorporation of newly formed bone as in the implants in Figures 1-4. In addition, the implants are provided with support or attachment parts in accordance with the above embodiments. In these cases too, the implants are rigid against torsion, as has been indicated by the cross sections d' , d' ' and d' ' ' in the figure.

Figure 6 shows an embodiment in which the parts extending from the center part of the implant are angled outward/downward by a certain angle α. In this

. .cas.e,_ the center part, has the shape of a cylindrical part 3a which has the abovementioned hole 3a' for the screw 11. In this case, the part 3a has a height which is such that the part 3a reaches above the bone surface and can thus function as a spacer element for a dental structure. In the figure, a center line for the implant is indicated by 14 and a plane at right angles to said center line is indicated by 15. The parts extending from the center part 3a are indicated in the figure by 3f , and 3g. The parts in question can form a circular unit- or have wing-shaped elements (cf. 3'''' in Figure 5) . The angle α here symbolizes the extent or extents of the part or parts 3f, 3g in relation to said horizontal plane 15. The implant is, in accordance with

-- the above, screwed-securely- by means of screws 6''' and

7' ' . Holes 8' are likewise arranged for incorporation of bone. In this case, the tops of the parts 3f and 3g and the cavities 8' are filled with drilled off bone, possibly in combination with bone substitute material which has been applied in the initial recess 2 in conjunction with the application of the implant in the particular reamed bore or equivalent. In this case, newly formed bone in the recesses 8' has also been indicated by 18 and the direction of incorporation of such newly formed bone has been indicated by arrows 19. In the present case, a barrier 16 of absorbable or nonabsorbable material can be applied such that it covers the drilled defect. As before, in this case too the degree of recessing of the implant is low in the cortical layer in question. The degree of recessing can in this case be determined with portions related to the parts 3f, 3g and the outer surface or surfaces 3h which are located on the attachment or support part 3a under the mucous membrane .

Figure 7 shows a further detailed illustrative embodiment in which the parts 3f and 3g' extending from the center part 3a have a more arc-shaped extent than in the case according to Figure 6. The arc-shaped extent follows to a greater degree the extension of the jaw "bone- "in the vertical section in question. The implant- shown in Figure 7 is secured and functions in a corresponding manner to the implant according to Figure 6. The dental structure (not shown) is secured in a manner known per se in the internal thread 3a' of the center part 3a.

Figure 8 shows, on an enlarged scale in relation to the embodiment according to Figure 5, an example of the design of an implant with center part 3a and wing- shaped elements 3i, 3k, 31 and 3m extending radially from this . The wings are arranged symmetrically with respect to the center part 3a. The design according to Figure 8 can also be - compared to the designs according to Figures 6 and 7. The implant is applied in a circular reamed hole and anchored correspondingly in holes in the cortical and/or subcortical parts of the jaw bone. The screw head 11 in this case has a diametrical groove 11a for a screwdriver.

Figure 9 shows the case in which the parts 3f' ' and 3g' ' extending from the center part 3a in principle extend parallel to the horizontal plane 15 at right angles to the center line 14 of the implant. It should be noted here that of the wings in the embodiment according to Figure 8, two opposite wings 3m and 3k can be inclined or curved according to Figures 6 and 7, respectively, while the two other wings 3i and 31 can be noncurved or noninclined in accordance with the embodiment according to Figure 9.

In Figure 9, the side surface or side surfaces 3o and 3p are placed opposite substantially only cortical and/or subcortical layers in the dentine 1. Likewise, the underside or undersides 3s, 3r of the implant lie substantially only against cortical or subcortical layers in the dentine. At least parts of said underside or undersides 3s and 3r bear against cortical and/or subcortical---layers-._ In-, the— last-men-tioned case, some outer'pπrts preferably lie against said layers . -

At- least parts of the underside 3s or -3r must be able to cooperate with cortical and/or subcortical layers in the bone. The parts in question can in this case consist of outer parts B, B' . In the case of a circular cross section, it is two opposite portions, or portions along the same diameter, which bear against the compact substance in question in the jaw bone. In the case with four wings, for example, according to Figure 8, it is therefore only the outer parts of two opposite wings which need to bear against the compact substance in the jaw bone. Other parts of the underside of the implant

- -can- bear- against trabecular parts of -the dentine and still effect a supporting function from these softer parts of the jaw bone.

In accordance with Figures lOa-lOc, said extension surface or the surface in the direction of extension (cf. the undersides 3s and 3r in Figure 9) can be divided into a number of component surfaces which interact with underlying cortical and/or subcortical layers of the jaw bone. The division can in principle be done with the aid of screws 20, 21 and 22 (Figure 10b) which are anchored at a distance from each other in the jaw bone in a manner known per se. The side surfaces 20a, 21a and 22a of the screws are in this case placed opposite said cortical and/or subcortical layers i , the screwed-in positions of the screws. The undersides 20b, 21b and 22b of the screws are also placed opposite said cortical and/or subcortical layers. The screws in this case function also as spacer elements and can extend with their central and/or upper parts through the periosteum and mucosa 4. At their upper ends 20c, 21c and 22c, the screws are connected to the connection element 23, see Figure 10c, which is screwed securely to said upper parts by means of screws 24, 25 an 26, respectively. A securing member 27 for a dental structure (not detailed) can be arranged on the element. The implant thus forms a homogeneous unit in accordance with Figure 5.

In accordance with Figure 10c, the screws can thus be applied to the cortical and/or subcortical layers of the bone. In the present case there can be at least two, m this case three, element parts 23', 23'' and 23' ' ' . Together, said element parts can form a common element, and the elements or element support a center part 27 which functions as a support or attachment part for the dental structure which can obtain a vertical support from the implant in question or can be secured in the latter, for example by means of screw connections, adhesive connections or in another way. The embodiment according to Figures 10c can have a connecting bar or connecting element either above or within the surface bone, but under the periosteum/mucosa or above the mucosa in the oral cavity. Figures 10, 10a, 10b and 10c show in sequence the application of the described arrangement. In accordance with Figure 10, a boring jig BJ is used for making bore holes. The bore holes are formed on both sides of the nerve branch Id. According to Figure 10a, the implant screws 20, 21 and 22 are then applied in the bored holes, and attachment parts for the bar or equivalent are applied on the upper parts of_. the implants or screws. According to Figure 10b, the bar/element is then applied to the implants/screws and securely screwed in these.

The attachments or supports according to the above are made substantially rigid and form prefabricated finished products/components. A spacer element or equivalent can be attached to the implant at a central or noncentral area, i.e. the attachment or support part is placed centrally or noncentrally . Since securing screws are not used, the torsional rigidity of the implant can be achieved by alternative means, for example . the recess design .(e.g. in. horizontal section) which —locks—the-— rotational movement of the implant relative to the jaw bone upon tightening of spacer element,- -dental structure, etc. In conjunction with the fitting of the implant, use can be made of means which initiate and/or stimulate bone growth (e.g. BMPs) .

Figures 11, 11a and lib show a sequence for application of an implant 28 indicated in Figure lib. According to Figure 11, a flap is formed in the mucosa, and the cortical bone 29 and possibly small parts • of the underlying trabecular bone 30 are sawn open or drilled

(with a trepan drill) , the sawn section being indicated by 31. The thus cut open or sawn open part of the bone

-29—has bee —indicated- by 29a. Before said sawing,- a central drilling of the bone part 29a has been carried out. The drilling in question, like the sawing, is intended to take place at a marked distance a from the nerve branch Id. The sawing/cutting and the drilling 32 are carried out after opening a flap in the mucosa, which flap opening thus exposes the bone part 29a from above. According to Figure 11a, the bone part 29a can thus be removed. Figure 11a also shows that before the removal, lower parts 29a' of the bone part 29a can be treated with an instrument by means of which the parts 29a' in question are removed. The implant has lower parts 28a and a center part 28b with center screw 28c.

Figure lie shows a slightly different method. Instead of reinserting the sawn-off part 29a in accordance with the above, in this case particulate autologous bone AB is used to fill the recess in question (cf. 34 in Figure lib) . The particulate bone is closed-in with the aid of a cover part, membrane or barrier TD which has a central recess through which the center part 28b can extend.

Figure lid shows a saw arrangement in the form of a "trepan auger" . The saw or drill has a center part 36 which is- guided in the. -recess 32, and the saw edge or cutting edge is indicated by 37.

In the embodiment according to Figure 12, a bone- growth function is used. The implant 28' is allowed to incorporate under the mucosa 29, and holes in the base plate or wing-shaped parts of the implant form access channels for the bone growth function an question. The newly formed bone has been indicated here by 38 and arrows for the bone growth function are also shown. The figures 12a, 12b and 12c show different embodiments of the base plate 28a' according to Figure 12.. According to Figure 12a, the different embodiments can consist of a circular plate 28a' ' with through-holes in the vertical direction- of the plate. According to Figure 12b, the base portion can also have wings 28a'' extending in a cross shape. A further design is shown by 28a"' in Figure 12c.

Figures 13, 13a, 13b and 13c show examples of structural configurations of the implant function. In this case the implant can be provided with or cooperate with a part which has a downwardly directed flange or downwardly directed flanges and an upwardly directed flange or upwardly directed flanges 40, which are indicated in Figure 13. The center part is shown by 41 and has an internal recess for receiving a screw or equivalent. A horizontal plate-shaped part is indicated by 42. In the case according to Figure 13a, the implant is provided only with downwardly turned flanges or parts. The downwardly directed flanges or parts (cf. also above) are located at a good distance from the nerve branch Id. Said downwardly directed flange or flanges extend down into the trabecular bone. Figures 13b and 13c show the implant structure in separate in a vertical section. With regard to the horizontal sections, reference can be made to Figures 12a and 12c.

Figures 14-14i show sequence images which are more — etailed—tha-n- h s been- described above. According to Figure' 14, a flap is opened in the soft tissue or mucosa and the center 43 for the implant is marked. A template^~4^~4- (Figures 14c-14-f) , for example of flexible plastic or metal, is placed in position. Silicon can also be used. According to Figure 14e, a round bore which can have a diameter of 1.8 mm is used to form a bore at the center of the template cross. The borin work can continue with a spiral drill of for example 2 mm "to the intended depth. Thereafter, in accordance with Figure 5, the boring is repeated with a round drill and spiral drill in the arms of the cross.

According to Figure 14f, the floor of the cross is evened with the aid of a reamer. Thereafter, an

"oscillating- saw- is applied-at the center, and one then cuts "round the horizon", see Figure 14g. In the position according to Figure 14h, implant templates can be used to check the fit in all directions. In the position according to Figure 14h, the implant is fitted in the cross, and the implant can be turned l/8^th of a turn, which gives the desired stability. Compact and spongy bone which has not been removed will cover the arms. Thereafter, the bored grooves can be filled again with accumulated bone. Cover screws are applied in the center part (cf. 28b in Figure lie), and the flap is replaced in the original position (sutures) . The tower or center part is covered by the flap, or the flap is punched out for the tower. An alternative to the application of an oscillating saw and installation of the implant is to place the implant without rotation. It then has to have substantial press-fitting laterally in all directions or alternatively be secured with miniature screws. The same applies if the implant is designed as a cross with peripheral ring, alternatively as a perforated plate. In order to increase the primary stability, the arm ends of the cross are angled upward or downward, or the peripheral ring is given a certain height (upward/downward) . In a further alternative, the plate can be given an edge (downward/upward) . If extending--- downward, preparation work is carried out using a small fissure drill or trepan drill.

Figures -=1-5', -15a-15f show another area of use of the implant in question and the manner of applying the implant. In Figure 15, a cavity in the upper jaw is indicated by 45, namely the maxillary sinus. The area is surrounded or delimited by a sinus mucosa 46. The oral mucosa is indicated by 47, and the periosteum placed or located inside the latter is indicated by 48. The cortical bone is indicated by 49, and the trabecular bone located inside the cortical bone is indicated by 50. The invention can be used especially on patients with a small bone height.

According to Figure 15a, a flap is opened in the mucosa 47 in accordance with the above, and the cortical bone and parts of the trabecular bone are sawn. Such sawing operations are indicated by 51 and 52 and can consist, for example, of so-called trepan grooves. The sawn

-cortical bone. -results in bone parts 49a and 49b. In a procedure used in conjunction with the invention, these parts can be knocked inward in the direction of the sinus mucosa 46.

According to Figure 15b, units or means 53 and 54 are then applied. A threaded sleeve 55 which effects a precise screwing function can be used in conjunction with the unit 53. In connection with the unit 54, use is made of a one-armed or multi-armed plate 56 which is provided with a central recess for the unit 54, which central recess has an internal thread 56a which cooperates with an external thread 54a on the unit 54. The unit 56 is screwed securely in the cortical or compact bone and the screws 57 can optionally penetrate even into the outer trabecular bone. This arrangement too affords a precise screwing-in function. In Figure 15b, the bone parts 49a and 49b have reached a position where the sinus mucosa has been curved inward, the inward- curves being_₌indicated .by 46a and 46b. The units 53 and 54 are inserted or screwed-in in- a manner which ensures...thai formation of new bone takes place in the

-area between -the bone parts 49a and- 49b' and said- sinus mucosa. Reference is also made to the Swedish patent application which was filed by the same Applicant and on the same day and which is directed at these types of bone formation unctions.

In Figure 15c, the course has progressed and the bone mass between the trabecular bone and the sinus mucosa has increased considerably. New bone thus formed has been indicated by 60 in Figure 15c. In one illustrative embodiment, the quantity of bone has increased by 60% -after- three -months-.- At -this stage the mucosa 47 has incorporated around the implant which, via parts 61 and 62, extends through the mucosa in question..

In the stage according to Figure 15d, the implant has been provided with cover screws 63 and 64. The implants 53' and„._54' shown in Figure 15d can consist of other units than the units 53 and 54 or can consist of the same units. These implants too can if appropriate cooperate with a sleeve 65 (partially shown) in accordance with the above. In the embodiment according to Figure 15e, the implants 53'' and 54'' have designs which ensure that they lift the sinus mucosa 46 at the screwing-in location without intermediate loose bone.

In Figure 15f, the implants or equivalent have been provided with cover screws at their outer parts. Members 68 and 69 ensuring the precision of the screwing-in function are used here. The members 68 are provided inter alia with through-holes via which the bone growth can take place and spread from the trabecular bone to the top face of the arrangement. In

Figure 15f, the units are indicated by 53''' and 54'''.

-The—- cover -screws axe ---labeled 70 and 71. Members ensuring the precision of the screwing-in function in connection with the unit 54''' are screwed securely with securing screws- 72 in- a manner similar to the above. The members 73 have through-holes in the same way as the member 68.

The invention is not limited to the embodiments shown by way of example above, and instead it can be modified within the scope of the attached patent claims and the inventive concept .

Claims

PATENT CLAIMS

1. An implant (3) which can be anchored in a recess (2) in bone (1) is intended to constitute an attachment or support for a structure for the human body, for example a dental structure, via one or more parts (12) extending through the bone and soft tissue, characterized in that the portion or portions (3f, 3f' ' , 3g, 3g' ) forming the attachment or support are arranged to penetrate with a low degree of penetration (H, H' , H' ' ) into the recess or recesses and with substantially their total area (3s, 3r) in the direction of extension, and in that, in -the -applied position of

-the attachment or support in the recess or recesses, - the- side surfaces of the portion or portions and at least parts, for¹ example outer parts, of said total area in the direction of extension can be placed opposite and cooperate substantially only with cortical and/or subcortical layers (la, lb) in the bone.

2. The implant as claimed in patent claim 1, characterized in that the attachment or support is designed as a flat and substantially rigid unit.

3. The implant as claimed in patent claim 1 or 2, characterized in that the attachment or support has vertical through-holes in which newly formed bone can grow as the attachment or support incorporates in the jaw bone.

4. The implant as claimed in patent claim 1, 2 or 3, characterized in that the attachment or support can penetrate fully into the recess or recesses and can be covered with newly formed bone during incorporation in the jaw bone.

5. The implant as claimed in any of the preceding patent claims, characterized in that the attachment or support is designed with arrangements, for example hole arrangements, for screwing it or securing it by means of screws or securing members in said cortical and/or subcortical layers .

6. The implant as claimed in any of the preceding patent claims, characterized in that the attachment or support is designed with one or more wing-shaped parts which extend from an attachment or support part located on the attachment or support for the part or parts extending through the periosteum/mucosa.

7. The implant as claimed in patent claim 6, characterized in that the wings are four in number and the attachment or support part is placed centrally, as viewed in the horizontal section of the attachment .

8. The implant as claimed in any of patent claims 1 to 6, characterized in that the attachment or support has a substantially rectangular or oval cross section in which an attachment or support part for the part or parts extending through the periosteum/mucosa are arranged in the central parts of the horizontal section and hole arrangements for tightening screws are arranged in the outer parts of the horizontal section.

9. The implant as claimed in any of patent claims 1 to 6, characterized in that the attachment or support is designed with a circular horizontal section, i.e. as a circular disk.

10. The implant as claimed in any of the preceding patent claims, characterized in that the attachment or support has a substantially plane upper part and an edge or flange or portions projecting down from its outer edge, and in that the upper part is completely or partially set into the recess or recesses and the side surfaces so that the downwardly projecting edge or flange or portions are placed opposite said cortical and/or subcortical layers.

11. The implant as claimed in any of the preceding patent claims, characterized in that the attachment or support has a central part or part placed eccentrically and extending through the periosteum/mucosa and, extending from this part, a - portion or— portions which - slope outward in relation to a horizontal section through the last- mentioned part .-.or.- are curved . in order to follow the vertical section contour of the. jaw bone.

12. The implant as claimed in any of the preceding patent claims, characterized in that the attachment or support functions as or is designed with a barrier of tissue-compatible material, for example with a titanium foil barrier.

13. The implant as claimed in any of the preceding patent claims, characterized in that the attachment or support is arranged in the recess or recesses at a marked distance above the nerve branch or nerve center.

14. The implant as claimed in any of the preceding patent claims, characterized in that the part or parts extending through the periosteum are connected to or integrated with the support or attachment part of the support or attachment.

15. The implant as claimed in any of patent claims 1 to 13, characterized in that the part or parts extending through the periosteum/mucosa only . rest or bear against the attachment or support part.

16. The implant as claimed in any of the preceding patent claims, characterized in that, in the case without tightening screws, the recess and the attachment or support are arranged for mutual stable application in the horizontal section.

17. The implant as claimed in patent claim 1, characterized in that the attachment or support is divided into two or more portions which can each be anchored in an assigned recess (bore) .

18. The^{" "}implant as claimed in patent claim 17, characterized in that each portion consists of or comprises a screw which is anchored in the recess

' via its inner end and which forms a part extending through the periosteum/mucosa with its middle and/ or upper parts, and in that the screws are connected to each other at their upper ends via elements for obtaining one common and continuous unit .

19. The implant as claimed in any of the preceding patent claims, characterized in that the extended area or areas have a total area of ca. 50 - 100 m² and,- -if of disk-shaped design, a thickness not exceeding 2 mm, preferably 0.5 - 1 mm.

20. The implant as claimed in any of the preceding patent claims, characterized in that the recess or recesses for the attachment or support have a depth of 2 - 5 mm, preferably ca. 3 mm.

21. A method for establishing in jaw bone (1) an implant (3) for a prosthetic (dental) structure in which holes (2) are made in the bone and an implant is then applied in the recess or recesses, characterized in that the implant (3) is designed with an attachment or support for the structure and with part (3a, 12) intended to extend through the periosteum/mucosa (4) of the bone to cooperate with the dental structure, in that the attachment or support is designed with a portion or portions (3f, 3f", 3g, 3g" ) of low height (H" ' ) which give a low degree of penetration (H' ) in the recess or recesses and with a substantial total area (3s, 3r) in the direction of extension, and in that the portion or portions are designed with side surfaces (3o, 3p) which, upon said application in the recess or recesses, together _wit.h„_at„.least_. parts, for example outer parts, of said- total—area in the direction of extension, are placed opposite substantially only cortical and/or subcortical layers (la, lb) in. the bone (1).

22. The method as claimed in patent claim 20, characterized in that the attachment or support or the portion or portions are covered by drilled-off bone, possibly in combination with bone substitute material .

23. The method as claimed in patent claim 21 or 22, characterized in that the attachment or support or the portion or portions are covered with autologous graft- bone and/or bone substitute.