Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0048—Connecting the upper structure to the implant, e.g. bridging bars
  • A61C8/005—Connecting devices for joining an upper structure with an implant member, e.g. spacers
  • A61C8/0065—Connecting devices for joining an upper structure with an implant member, e.g. spacers with expandable or compressible means
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0018—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools characterised by the shape
  • A61C8/0033—Expandable implants; Implants with extendable elements
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0048—Connecting the upper structure to the implant, e.g. bridging bars
  • A61C8/005—Connecting devices for joining an upper structure with an implant member, e.g. spacers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0048—Connecting the upper structure to the implant, e.g. bridging bars
  • A61C8/005—Connecting devices for joining an upper structure with an implant member, e.g. spacers
  • A61C8/0056—Connecting devices for joining an upper structure with an implant member, e.g. spacers diverging in the apical direction of the implant or abutment
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0048—Connecting the upper structure to the implant, e.g. bridging bars
  • A61C8/005—Connecting devices for joining an upper structure with an implant member, e.g. spacers
  • A61C8/0068—Connecting devices for joining an upper structure with an implant member, e.g. spacers with an additional screw
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0048—Connecting the upper structure to the implant, e.g. bridging bars
  • A61C8/005—Connecting devices for joining an upper structure with an implant member, e.g. spacers
  • A61C8/0054—Connecting devices for joining an upper structure with an implant member, e.g. spacers having a cylindrical implant connecting part

Definitions

• the invention relates to a multiblock dental implant, intended for placing and maintaining a dental prosthesis on a bone site. It extends to accessories of this implant: instrument intended to facilitate its installation, temporary protective element before fitting the prosthesis.
• Dental implantology is moving more and more towards multi-block implants which consist of two separate parts, placed successively: on the one hand, an implant root formed by a tubular part which is anchored in the bone site, d 'on the other hand, a suprastructure composed of a fixation tail in the implant root and a false prosthesis support stump.
• the abutment and the fixing tail have collinear axes, while in the so-called angulated implants, the axes of these elements form an angle of up to 30 °.
• the implant root is first anchored in the bone site by screwing or any other means (patents DE 1,961,531, EP 0.114.955, US 3,708,883 ...), then the suprastructure is subject to said implant root by means of its fixing tail so that the abutment comes to be in the appropriate position.
• This fixation of the tail in the implant root is essentially carried out by two conventional techniques.
• the tail of the suprastructure being formed by a smooth rod, this is definitively sealed in the tubular implant root by means of a cement; however, in case of clinical problems, it is no longer possible to remove the suprastructure.
• the tail of the suprastructure is screwed into the implant root by means of a thread and a tapping which are provided on these elements (cf. US Pat. No. 3,589,011).
• the suprastructure - is then removable, but its positioning is imprecise, both in the longitudinal direction (along the axis of the implant), because it is difficult, during screwing, to determine the limit of tightening stop , as regards the orientation of said suprastructure around its axis, because this orientation conditioned by the end of screwing position is very random; this angular imprecision constitutes a serious defect in the case of angled implants which are very delicate to position in an appropriate manner with this type of fixation.
• Patent FR 1 - "90.05938 in the name of the applicant describes a multiblock implant which eliminates these defects.
• this implant (a) the suprastructure is provided with a hollow core which extends over its entire length and opens out at the end free from the false stump, a converging ramp being provided at the free end of the tail,
• said tail is provided with slots extending from its free end over part of its length, in order to delimit several sectors,
• said tail contains a mechanical pressure member, movable between an active position where this member exerts pressure on the converging ramp tending to spread the sectors apart and a passive position where said sectors remain free,
• maneuvering means are associated with the pressure member in order to allow said member to be displaced longitudinally towards its active position and to block it under pressure against the converging ramp.
• the present invention relates to an improved implant of the type mentioned above. It proposes to improve the fixation of the suprastructure on the implant root and in particular to increase the precision of this fixation along the longitudinal axis of the implant (penetration depth of the tail into the implant root perfectly determined, improvement of the locking in this position both in rotation and in longitudinal translation).
• Another objective of the invention is to facilitate the handling of the implant and the laying operations.
• the implant of the aforementioned type is characterized in that:
• the implant root has in its internal bore a relief -or hollow structure longitudinally positioned to be located at the level of the sectors of the tail of the suprastructure when the latter is in place in the implant root,
• the tail of the suprastructure has, externally at its sectors, a hollow-or relief-structure, combined with the structure of the implant root and adapted to cooperate with the latter when the tail is in place in the implant root,
• the tail slits are adapted to allow the sectors to undergo:
• the tubular implant root is anchored in the bone site in a traditional manner, in particular by screwing; said implant root is in particular provided for this purpose with an external thread in order to effect this screwing, this thread possibly being able to be self-tapping.
• the suprastructure is fixed on the implant root thus anchored, by introducing its fixing tail inside the bore of the root, the pressure member being in passive position and leaving the sectors of the tail free to retract; the passage of the relief structure of the implant root (or of the tail) is effected by a centripetal retraction of the sectors of the tail by the play of the elasticity of these.
• the hollow and raised structures of the tail and the root cooperate, conditioning a precise predetermined depth of penetration of the first into the second.
• the tail is retained in the implant root but can be angularly positioned appropriately.
• the operating means it suffices to actuate the operating means so that the pressure member generates the expansion of the tail and its blocking inside the implant root; the suprastructure is then fixed in a precise and resistant manner in the appropriate position, the hollow and relief structures cooperating without the possibility of being released from one another due to the centrifugal blocking of the sectors of the tail.
• the sectors of the tail are radially released and the tail can be extracted thanks to the centripetal retraction faculty of said sectors.
• the implant root has in its bore a relief structure constituted by an annular rib which projects on its internal surface, while the tail of the suprastructure has externally a hollow structure constituted by a groove at the sector level.
• the centripetal retraction of the sectors occurs when the tip of the tail comes into contact with the rib of the implant root; preferably, the tail of the suprastructure is chamfered at its end along its peripheral border in order to facilitate the retraction of the sectors when the said end is pressed against the rib of the implant root.
• centripetal retraction is ensured by the support of the lower flank (located towards the free end) of the groove of the tail against the lower flank of the rib of the implant root; preferably, these sides are frustoconical in order to facilitate "centripetal retraction.
• the implant root of the implant according to the invention has a cylindrical internal bore whose surface is smooth (with the exception of the abovementioned relief structure). With equal dimensions, such an implant root benefits from mechanical characteristics far superior to those of known roots achieving the fixation of the tail by screwing; in fact, the zones of least resistance, incipient fractures, which exist in the known implants between the facing threads, are eliminated.
• the implant according to the invention can be of the straight type; the tail and the false stump of the superstructure then have collinear axes.
• the means for operating the suprastructure advantageously comprise a screw which is screwed into a tapped portion of the hollow core of the abutment and which is extended by a rod in the tail of the suprastructure; this rod ends at the converging ramp by a convex end which constitutes the pressure member.
• Such an embodiment leads to an implant, economical, which benefits from all the functional advantages of the invention.
• the implant according to the invention can also be of the angled type; the tail and the abutment of the suprastructure then form between them a predefined angle, for example 6 °, 12 °, 20 ° or 30 °.
• the means for operating the suprastructure advantageously comprise, on the one hand, a screw screwed into a tapped portion of the hollow core of the abutment, on the other hand, several elements with convex ends, arranged in contact with each other in the 'hollow soul; the screw bears against the first element, while the last element located at the level of the converging ramp has a convex end constituting the pressure member.
• the elements which are housed at the bent portion of the suprastructure are preferably substantially spherical balls.
• the invention extends to a delivery instrument intended to facilitate the positioning of the implant root of the implant defined above.
• This instrument comprises a barrel, an operating head surmounting said barrel and a tail extending the barrel opposite the head; it is essentially characterized in that:
• the head and the tail have a hollow core extending over their entire length and provided with a converging ramp at the free end of the tail,
• said tail is provided with slots extending from its free end over a fraction of its length, in order to delimit several sectors,
• Said tail externally comprises, at the level of its sectors, a hollow structure (or relief), combined with the structure of the implant root and adapted to cooperate with the latter when the tail is in place in the implant root,
• the tail slits are adapted to allow the sectors to undergo:
• a retraction radial allowing them to retract in the centripetal direction over a depth at least equal to the thickness of the relief structure of the implant root (or tail),. on the other hand, a radial expansion,
• the hollow structure (or relief) of the tail is profiled to ensure the centripetal retraction of its sectors when it is placed in the implant root or when it is removed,
• a screw is screwed into a tapped portion of the hollow core of the head and the barrel, said screw extending, in the tail of the suprastructure, by a rod which ends at the converging ramp by a convex pressure end .
• such an instrument is capable of playing the role of means of gripping and retaining the implant root during its anchoring in the bone site in order to facilitate this anchoring.
• the invention also extends to a protective element intended to temporarily cover the implant root of the implant defined above;
• this protective element comprises a tail surmounted by a collar, and is essentially characterized in that:
• the tail has a hollow core over at least a fraction of its length, said hollow core extending to its free end opposite the collar,
• said tail is provided with slots extending from its free end over part of its length, in order to delimit several sectors,
• said tail has externally at its sectors, a hollow structure (or relief), combined with the structure of the implant root and adapted to cooperate with the latter when the tail is in place in the implant root,
• the tail slits are adapted to allow the sectors to undergo a radial retraction their allowing to retract in the centripetal direction to a depth at least equal to the thickness of the relief structure of the implant root (or tail),
• the hollow structure (or relief) of the tail is profiled to ensure the centripetal retraction of its sectors when it is placed in the implant root or when it is removed.
• the collar of said protective element is preferably provided with a tapped hole for the establishment of a cap composed of a head and a short threaded screw. This cap facilitates handling during the healing phase of soft tissue, and serves as a gauge to define the gingival height.
• FIGS. 1 a and 1 b are axial sections on an enlarged scale representing a straight implant according to the invention, respectively its suprastructure and its implant root,
• FIGS. 2a and 2b are cross sections respectively of the suprastructure by a plane AA and of the implant root by a plane BB,
• FIGS -3a, 3b, 3c and 3d are schematic sections illustrating the placement of the suprastructure in the implant root
• - Figure 4 is a schematic section showing the implant and its prosthesis in place on a site
• FIG. 5 is an axial section of another embodiment (angled implant) ready to receive his prosthesis
• FIG. 6 is an axial section of a delivery instrument in accordance with the invention, while FIG. 7 illustrates, in axial section, this instrument carrying an implant root,
• FIGS. 1-4 scale of the order of 8 8
• the multiblock dental implant shown by way of example in FIGS. 1-4 is a straight implant, composed of an implant root 1 (FIGS. 1b, 2b), for example made of titanium, which has a tubular shape whose internal bore 2 is closed by a bottom 3 provided with external recesses 4 intended to prevent rotation of the implant root, once the latter in place.
• the implant root On its external cylindrical face, the implant root has a thread which can be self-tapping, with a view to its anchoring by screwing in the maxillary site.
• the internal bore 2 of the root is provided with an annular rib 6 which projects relative to its cylindrical surface, this surface being smooth in its other parts.
• This rib is arranged in the lower half of the root (bottom side 3) and is delimited by a frustoconical lower flank 6b and a frustoconical upper flank 6a, separated by a cylindrical face 6c.
• the taper angle ⁇ of the lower flank is greater than the taper angle ⁇ of the upper flank; for example, the angle ⁇ can be between 10 ° and 25 °, and the angle ⁇ between 35 ° and 55 °.
• the other part of the implant is also made of titanium and comprises a false stump 8, a tail 9 and a gingival junction 10 between these elements.
• the longitudinal axis of the abutment and the gingival junction is collinear with that of the tail. Shoulders such as 10a and 10b limit the gingival junction 10: they are called to correspond respectively with the bone / gum interface and with the external surface of the gum, as illustrated in FIG. 4.
• the suprastructure 7 is pierced right through along its longitudinal axis, with a hollow core 11 of circular section.
• this hollow core comprises a converging ramp 12 of frustoconical shape, the apex angle of which is in particular between 50 ° and 70 °, in the example of the order of 60 ° .
• the hollow core 11 is tapped over a portion 13 of its length which extends to the free end of its false stump, so as to allow the screwing of a screw.
• the tail 9 of the suprastructure has an external diameter slightly smaller than that of the bore 2 of the implant root so as to be able to lodge with gentle friction therein. Said tail 9 is separated over a fraction of its length into several sectors such as 9a, by longitudinal slots 1 (in the example four in number) which start from the free end of the tail. Thus, this tail part can undergo a retraction or a radial expansion by the play of the elasticity of the sectors 9a. It should be noted that the hollow core of the tail 9 is of cylindrical shape with a smooth surface and has only the aforementioned slots 14 and the converging ramp 12 at its end.
• the suprastructure 7 contains a screw 15 screwed into the threaded portion 13 of its hollow core; this screw is extended by a cylindrical rod 16 which extends along the tail and ends at the converging ramp 12 by a convex end 17, in the hemispherical example.
• the screw 15 provided with a hollow imprint 15a acts as an operating means making it possible to move the end 17 longitudinally (which acts as a pressure member) with a view to placing it under pressure against the converging ramp 12 and to block it in this position (active position) or, on the contrary, to move it away from said ramp 12 (passive position: FIG. 1a). In the active position, the pressure end 17 tends to spread the sectors 9a of the tail, while, in the passive position, it leaves them free to play by the play of their radial elasticity.
• the tail 9 has externally at its sectors 9a, a groove 18 of shape conjugated to that of the annular rib 6 of the implant root.
• This groove is longitudinally positioned so as to correspond with said rib when the tail is in place in the implant root.
• the groove 18 is shaped to contain the rib 6; for this purpose, it is delimited by a lower conical flank 18b with a conical angle ⁇ between 35 ° and 55 ° and by an upper frustoconical flank 18a with a conical angle ⁇ between 10 ° and 25 °, separated by a cylindrical surface. 18c * (bottom of the throat).
• the dimensions of the groove 18 correspond to the clearance close to those of the rib 6.
• the tail 9 of the suprastructure is chamfered at its end on its peripheral edge 9b.
• the practitioner After anchoring the implant root 1 in the bony site of the maxilla, the practitioner introduces the tail 9 of the suprastructure into the bore of said root, as illustrated in FIG. 3a.
• the rod 16 and the pressure end 17 are in the passive position and leave the sectors 9a of the tail free to play radially.
• the longitudinal slots 14 which delimit the sectors have a width greater than approximately one and a half times the thickness of the annular rib 6 of the root, so that the sectors can undergo a radial retraction in the direction centripetal over a depth at least equal to the thickness of the rib 6.
• the chamfered end 9b of the tail takes support against the frustoconical side 6a of the rib 6 and causes a radial retraction of the sectors 9a, which retract, allowing the penetration of the tail to continue.
• the rod 16 and its pressure end 17 in the passive position have no contact with the tail and leave the sectors of the latter free to retract.
• the sectors return to their natural position by the play of their elasticity: the throat 18 of the tail contains the rib 6 of the root.
• the practitioner operates the screw 15 " by means of an awning key in order to pressurize the hemispherical end 17 against the converging ramp ⁇ 12.
• the rib 6 and the groove 18 are locked into each other extremely efficiently, without the possibility of relative movement, thereby obtaining an extremely strong fixation of the suprastructure relative to the implant root.
• the suprastructure can be easily removed from the root if necessary It suffices to maneuver the screw 15 in the opposite direction to move the pressure end 17 upwards and release the sectors 9a.
• the tail can then be extracted by an axial pull which generates the centripetal retraction of the sectors (retraction facilitated by the frustoconical shape of the lower flanks of the groove and of the rib.
• FIG 4 shows the implant installed on the site with its prosthesis 19, which is fixed to the abutment 8 by any means.
• this prosthesis is made of ceramic and has a metallic internal cover 19a which is glued to the abutment.
• the implant abutment according to the invention can be adapted to allow any other type of fixation of the prosthesis, for example a screw fixation (thanks to conjugate threading and tapping provided on the abutment and the prosthesis, or by clipping).
• FIG. 5 illustrates the case of an angled implant in which the axis of the tail of the suprastructure makes a predetermined angle with the axis of the abutment and the gingival junction.
• the implant root is identical to that already described.
• the suprastructure has characteristics identical to those already described (slots, groove, converging ramp of the tail, etc.) with the exception of the differences described below.
• the maneuvering screw 20 is of reduced length and has a hemispherical end 21 which comes to bear with the first ball of a row of spherical balls 22, 23 (in the example two in number) located at the bent portion of the suprastructure. These balls are themselves in abutment against elements with hemispherical ends 24, 25 (in the example two in number).
• Each element 24, 25 is in the example formed by a cylindrical body having two hemispherical ends.
• the last element 25 acts as a pressure member and its hemispherical end is situated at the level of the converging ramp of the tail in order to be able to exert pressure thereon.
• Such arrangements condition an operation similar to that already described and make it possible to provide any angulation between tail and false stump.
• the implant according to the invention described above lends itself to easy positioning by means of a positioning instrument as illustrated in FIG. 6.
• This instrument provides a grip of the implant root to achieve the installation thereof by screwing.
• the target instrument comprises an operating head 26, in particular square, which can be turned by means of a key, a barrel 27 of length. appropriate and a tail 28 extending the barrel opposite the head.
• An assortment of instruments with different barrel lengths can be provided to suit all practical cases.
• the tail 28 is identical to the tail 9 of the suprastructure (FIG. 1a): it has the same structures (slots, groove, converging ramp, chamfer, etc.) and is thus able to penetrate an implant root as illustrated in Figure 7, to be snapped on, fixed and locked.
• a screw 29 is screwed into a threaded portion 30 formed in the hollow core of the head 26 and of a part of the barrel 27.
• This screw is extended by a rod 31 which extends to the inside of the bole and the tail, and ends at the level of the converging ramp of the tail, by a hemispherical pressure end.
• the screw 29 has an external operating head 29a, the rotation of which allows extremely strong locking of the tail 28 in the implant root to be placed. After installation, unlocking is carried out by reverse rotation of the screw 29 and the instrument can be removed.
• Figures 8a and 8b show a protective element to temporarily cover an implant root after its installation (illustrated in Figure 8c). This element will protect the internal bore of the root during the nurse period during which healing of the soft tissues around the root takes place (the establishment of the suprastructure being performed after this period).
• the protective element comprises a tail 32 surmounted by a collar 33 which is provided with a tapped hole 34 for the purpose of installing a cap composed of a head 35 and a short threaded rod 36; the head 35 is provided with an imprint 35a.
• the tail 32 of the protective element is identical to the tail 9 of the suprastructure. However, its maintenance is carried out by simple clipping in the root implant and it is not equipped with internal operating means and pressure member; the hollow core of said tail opens only at its lower free end.
• This protective element is put in place without an instrument by simply pressing in and clipping into the implant root. It can be removed by exerting an axial pull on the head 35.
• the head 35 facilitates handling and serves as a gauge for defining the gingival height. An assortment of several caps with heads of different heights can be provided to suit all practical cases.

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• Health & Medical Sciences (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Dentistry (AREA)
• Epidemiology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Dental Prosthetics (AREA)

Applications Claiming Priority (3)

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• 1992
  • 1992-04-21 FR FR9205122A patent/FR2690069A1/fr active Granted
• 1993
  • 1993-03-18 EP EP93922321A patent/EP0637228A1/fr not_active Withdrawn
  • 1993-03-18 CA CA002118408A patent/CA2118408A1/fr not_active Abandoned
  • 1993-03-18 WO PCT/FR1993/000275 patent/WO1993020773A1/fr not_active Application Discontinuation

Non-Patent Citations (1)

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