WO2002015813A1

WO2002015813A1 - Fastening system and method for dental implant abutment

Info

Publication number: WO2002015813A1
Application number: PCT/CA2001/001192
Authority: WO
Inventors: Michel Poirier
Original assignee: Technique D'usinage Sinlab Inc.
Priority date: 2000-08-25
Filing date: 2001-08-21
Publication date: 2002-02-28
Also published as: AU2001287412A1

Abstract

A method and a system for securing a dental implant abutment (12) to an implant (14) inserted into a patient's jawbone. The system includes a fixation member (30) having a threaded shank (44) adapted to threadably engage the implant (14) in order to secure the abutment (12) to the implant (14). The fixation member (30) is provided with an elongated male hexagonal head (46) sized to extend outwardly of the abutment (12) to facilitate the screwing of the fixation member (30) and adapted to be subsequently cut to a selected length so that the male head (46) be slightly recessed in the abutment (12) once fully tightened. A cap (52) having a reference mark (58) defined thereon is adapted to be fitted over the male head (46) to close the fixation receiving bore (28) of the abutment (12) and provide a visual indication of eventual loosening of the fixation member (30).

Description

FASTENING SYSTEM AND METHOD FOR DENTAL IMPLANT ABUTMENT

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to dental implantology processes and, more particularly, to a new system and method for securely fastening a dental implant abutment to an implant inserted in a patient's j awbone .

2. Description of the Prior Art It is known to mount a dental prosthesis to a superstructure secured to a number of dental implants inserted into the upper or lower jawbone of a patient. The superstructure typically consists of a number of tubular abutment feet adapted to extend down to the top of the implants and having an upper bridge structure adapted to extend inside of the dental prosthesis to support the same. Biocompatible screws are typically inserted through the tubular abutment feet and screwed into the implants in order to secure the superstructure thereto. Such conventional screws are each provided with a head defining a recess configured to receive, in a complementary fashion, an associated male engaging portion of a driving tool used to tighten the screws. Sometimes, it becomes difficult to insert the male engaging portion of the tool into the tubular abutment feet because of the depth thereof and also because of the patient limited capacity to open his mouth, thereby rendering hazardous the installation of the superstructure onto the implants.

For instance, United States patent No. 5,733,122 issued on March 31, 1998 to Gordon discloses an attachment assembly wherein a screw having a head defining a polygonal recess extends downwardly from a bottom end of an elongated through bore of a dental prosthesis abutment for threadably engaging an implant in order to securely fasten the dental prosthesis thereto .

SUMMARY OF THE INVENTION It is therefore an aim of the present invention to provide a novel method for facilitating the attachment of a dental prosthesis abutment to an implant .

It is also an aim of the present invention to provide a new attachment assembly having indicators for providing a visual indication of eventual loosening of a fixation member forming part of the attachment assembly.

Therefore, in accordance with the present invention, there is provided a method of securing a dental prosthesis abutment to an implant inserted into a patient's jawbone, comprising the steps of: a) positioning the dental prosthesis abutment over the implant, b) inserting a threaded fastener having an elongated male head into a fastener receiving opening defined through the dental prosthesis abutment and then with a tool having a female engaging portion screwing the threaded fastener into the implant to a fully engaged position and c) cutting the elongated male head to a desired length.

In accordance with a further general aspect of the present invention, there is provided an attachment assembly for securing a dental prosthesis to an implant inserted in a patient's jawbone, comprising a dental prosthesis abutment for receiving a dental prosthesis, a fixation member having a threaded shank portion adapted to extend through a through bore defined in said dental prosthesis abutment for threadably engaging an implant in order to securely fasten said dental prosthesis abutment to the implant, said fixation member further including an elongated head having opposed proximal and distal ends, said distal end being displaceable between a first position wherein said distal end is located outwardly of said through bore at a distance from a top surface thereof even when said fixation member has been fully tightened, thereby facilitating screwing of said fixation member, and a second position wherein a selected length of said elongated head has been cut off so that said distal end be substantially flush with said top surface of said through bore. In accordance with a further general aspect of the present invention there is provided a fixation member in combination with a dental prosthesis abutment adapted to be secured to an implant inserted in a patient's jawbone for supporting a dental prosthesis, said fixation member comprising a threaded shank portion adapted to extend through a through bore defined in said dental prosthesis abutment for threadably engaging an implant in order to securely fasten said dental prosthesis abutment to the implant, and an elongated head having opposed proximal and distal ends, said distal end being displaceable between a first position wherein said distal end is located outwardly of said through bore at a distance from a top surface thereof even when said fixation member has been fully tightened, thereby facilitating screwing of said fixation member, and a second position wherein a selected length of said elongated head has been cut off so that said distal end be substantially flush with said top surface of said through bore .

In accordance with a further general aspect of the present invention there is provided a threaded fastener in combination with a dental prosthesis abutment adapted to be secured to an implant mounted in a patient's jawbone, said threaded fastener comprising a threaded shank portion adapted to extend through a through bore of said dental prosthesis abutment for threadably engaging the implant, and an elongated head engageable by a driving tool for allowing said threaded fastener to be screwed into the implant, said elongated head having a distal end portion of substantially uniform cross-section sized to extend outwardly of said through bore to facilitate screwing of said threaded fastener into the implant and adapted to be subsequently transversally cut at a desired location therealong after the threaded fastener has been fully tightened so that said distal end portion be recessed in the fastener receiving opening of the dental prosthesis abutment

BRIEF DESCRIPTION OF THE DRAWINGS Having thus generally described the nature of the invention, reference will now be made to the accompanying drawings, showing by way of illustration a preferred embodiment thereof, and in which:

Fig. 1 is a perspective exploded view of an attachment assembly used for attaching a dental prosthesis superstructure to a number of implants inserted in a patient's jawbone in accordance with a preferred embodiment of the present invention;

Fig. 2 is a schematic perspective view of an abutment foot of a dental implant superstructure securely fastened to an implant by means of a male fixation member in accordance with a preferred embodiment of the present invention;

Fig. 3 is a longitudinal cross-sectional view of the abutment foot illustrated in Fig. 2;

Fig. 4 is a perspective view of the male fixation member illustrated in Fig. 2;

Fig. 5 is a longitudinal cross-sectional view of a cap adapted to be fitted over an elongated head of the male fixation member; and

Fig. 6 is a longitudinal cross-sectional view of a second embodiment of a cap adapted to be fitted over an elongated head of the male fixation member .

DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 1 illustrates an attachment assembly 10 used for securely fastening a dental prosthesis abutment, such as a superstructure 12, to a number of implants 14 previously implanted into a patient's j awbone B . Each implant 14 has a threaded shank portion

16 and a hexagonal head portion 18 adapted to be engaged by a female driving tool (not ^■ shown) for screwing the implant 14 into the jawbone B. Each implant 14 defines a longitudinal central bore 20. A circular rim 22 is formed at a proximal end of the hexagonal portion 18 of each implant 14 for providing a uniform bearing surface for the superstructure 12.

The superstructure 12 generally comprises a number of cylindrical abutment feet 24 distributed along an arcuate bridge 26 adapted to extend within the lower portion of a denture structure 27 to support the same on the implants 14. As seen in Figs. 2 and 3, each abutment foot 24 defines a central through bore 28 adapted to receive a male fixation member 30 for securing the superstructure 12 to the implants 14. As seen in Fig. 3, the central through bore 28 has a bottom enlarged section 32 for accommodating the hexagonal head portion 18 of an associated implant 14 when the abutment foot 24 is seated on the top surface of the rim 22. An annular shoulder 34 is defined at a junction of a reduced intermediate section 36 and an enlarged intermediate section 38 of each through bore 28. Finally, each through bore 28 is provided with an enlarged top section 40. As seen in Figs. 1, 2 and 4, the fixation members 30 used to secure the abutment feet 24 of the superstructure 12 to the implants 14 each has a uniform threaded shank portion 44 and an elongated hexagonal head 46. Each fixation member 30 is adapted to be inserted into a corresponding through bore 28 with the threaded shank portion 44 of the fixation member 30 depending downwardly from the bottom enlarged section 32 of the through bore 28 for threadably engaging the longitudinally extending central bore 20 defined in the underlying implant 14. As seen in Fig. 1, the length of the elongated hexagonal head 46 of each fixation member 30 is such as to ensure that a distal end 48 thereof be at a distance from a top surface of the through bore 28 in which the fixation member 30 is placed, ' thereby facilitating the screwing of the latter into the implant 14 with a driving tool (not shown) having a hexagonal female portion adapted to receive a portion of the elongated head 46 to transmit a torque to the fixation member 30.

Once the fixation member 30 has been properly tightened (i.e. approximately 20 Newton/cm) with the undersurface of ^* the proximal end 50 thereof uniformly pressed against the internal annular shoulder 34 of the associated abutment foot 24, a cutting line 47 (see Fig. 4) is defined on the elongated head 46 at a location which is slightly recessed in the through bore 28. Once the cutting line 47 has been defined, the fixation member 30 is unscrewed, removed from the through bore 28 and then transversally cut along the cutting line 47. Thereafter, the fixation member 30 is screwed back into the implant 14 to a fully screwed position where the new distal end 48 of the elongated head 46 is slightly recessed in the through bore 28. The elongated head 46 is of uniform , cross-section all along the length thereof and can thus be transversally cut off at any selected location between the distal and proximal ends 48 and 50 thereof so as to ensure that all the fixation members 30 be equally recessed in the abutment feet 24.

The top enlarged section 40 of each through bore 28 is sized to accommodate the female hexagonal portion of the driving tool used to tighten the fixation members 30.

As seen in Fig. 2, a cap 52, preferably made of Teflon or Nylon, can be fitted over the elongated hexagonal head 46 of each fixation member 30 to close the associated through bore 28 once the fixation member 30 has been properly installed therein, thereby preventing food particles or the like from entering and remaining trap in the through bore 28. As seen in Fig. 5, each cap 52 has a cylindrical outer surface 54 having a cross-section generally corresponding to the cross-section of the top enlarged section 40 of each through bore 28 and an undersurface defining a hexagonal recess 56 for receiving in a complementary fashion a portion of the elongated head 46 of an associated fixation member 30. The hexagonal cross- section of the recess 56 of the cap 52 and the elongated head 46 prevent any relative rotational movement between the cap 52 and the fixation member 30 on which the cap 52 is mounted. The cap 52 could be dimensioned in a lengthwise direction so as to extend beyond the top surface of the through bore 28 and to facilitate the installation thereof. The portion of the cap 52 which extends outwardly of the through bore 28 could be subsequently cut so as to be flush with the top surface of the through bore 28.

As seen in Fig. 2, a reference mark 58 can be defined on each cap 52 once the same has been installed on a fully inserted fixation member 30 to cooperate with a second reference mark 60 defined on the superstructure 12 at a location adjacent the top surface of each through bore 28 thereof. The reference mark 58 is defined so as to be in alignment with the second reference mark 60 to provide visual indication of any eventual loosening of the fixation member 30 on which the cap 52 is installed. If the reference lines 58 and 60 become offset, the surgeon has only to remove the cap 52 and retighten the fixation member 30. Thereafter, a new cap 52 can be placed back on the fixation member 30 and a new reference line 58 be defined thereon so as to be aligned with reference line 60. Fig. 6 illustrates another embodiment of the cap 52 of Fig. 5. For simplicity and brevity, like features are given the same reference numerals, and a description of these features is omitted. Essentially, the cap 52' of Fig. 6 only differs from the cap 52 of Fig. 5 in that it is provided at a top end portion thereof with a continuous annular seal 62' adapted to sealingly engage the wall 64 (see Fig. 3) circumscribing the top enlarged section 40 of the through bore 28 in which the cap 52' is inserted so as to prevent food particles or the like from entering into the through bore 28.

Although the present invention has been described in the context of a superstructure adapted, to be mounted to a number of implants, it is understood that the present invention could be applied as well to other dental prosthesis abutment structures, such as crowns or the like.

Claims

CLAIMS :

1. A method of securing a dental prosthesis abutment to an implant inserted into a patient's jawbone, comprising the steps of: a) positioning the dental prosthesis abutment over the implant, b) inserting a threaded fastener having an elongated male head into a fastener receiving opening defined through the dental prosthesis abutment and then with a tool having a female engaging portion screwing the threaded fastener into the implant to a fully engaged position and c) cutting the elongated male head to a desired length.

2. A method as defined in claim 1, wherein step c) consists of removing a portion of the elongated male head which extends outwardly of the fastener receiving opening.

3. A method as defined in claim 2, wherein said elongated male head is cut so as to be slightly recessed within the fastener receiving opening of the dental prosthesis abutment.

4. A method as defined in claim 3, further including the step of closing said fastener receiving opening by installing a cap on said elongated male head after step c) .

5. A method as defined in claim 4, further comprising the step of providing corresponding reference marks on said cap and said dental prosthesis abutment to provide visual indication of eventual loosening of the threaded fastener.

6. A method as defined in claim 5, wherein the step of providing corresponding reference marks on said cap and said dental prosthesis abutment is effected by providing one of the dental prosthesis abutment and the cap with a pre-formed reference mark, and by making a corresponding reference mark on the other one of the cap and the dental prosthesis abutment so that the pre-formed reference mark and the corresponding reference mark be in alignment once the threaded fastener has been screwed and the cap installed thereon.

7. A method as defined in claim 6, wherein the step of closing said fastener receiving opening by installing a cap on said elongated male head is effected by slidably fitting the cap in complementary fashion over a terminal polygonal cross-sectional portion of the elongated male head of the threaded fastener, thereby preventing relative rotational movement between the cap and the threaded fastener.

8. A method as defined in claim 1, wherein step c) includes the steps of: first defining a cutting line on the elongated male head, unscrewing the threaded fastener from the implant, removing the threaded fastener from the fastener receiving opening, cutting the threaded fastener along the cutting mark appearing thereon, and screwing the threaded fastener back into the implant .

9. An attachment assembly for securing a dental prosthesis to an implant inserted in a patient's jawbone, comprising a dental prosthesis abutment for receiving a dental prosthesis, a fixation member having a threaded shank portion adapted to extend through a through bore defined in said dental prosthesis abutment for threadably engaging an implant in order to securely fasten said dental prosthesis abutment to the implant, said fixation member further including an elongated head having opposed proximal and distal ends, said distal end being displaceable between a first position wherein said distal end is located outwardly of said through bore at a distance from a top surface thereof even when said fixation member has been fully tightened, thereby facilitating screwing of said fixation member, and a second position wherein a selected length of said elongated head has been cut off so that said distal end be substantially flush with said top surface of said through bore.

10. An attachment assembly as defined in claim

9, wherein said distal end is slightly recessed in said through bore when assuming said second position, and wherein said attachment assembly further includes a cap adapted to be mounted on said elongated head to close said through bore.

11. An attachment assembly as defined in claim

10, wherein said cap is adapted to be slidably fitted over said elongated head to close an enlarged terminal section of said through bore, said enlarged terminal section defining a free space about said elongated head for accommodating a female engaging portion of a driving tool used to tighten said fixation member into the implant.

12. An attachment assembly as defined in claim 10, wherein said cap is mounted to said elongated head of said fixation member so as to prevent relative rotational movement therebetween, and wherein said cap and said dental prosthesis abutment are provided with cooperating reference marks for providing a visual indication of eventual loosening of said fixation member.

13. An attachment assembly as defined in claim

12, wherein said cap defines a recess having a polygonal cross-section for receiving a portion of said elongated head in a complementary fashion.

14. An attachment assembly as defined in claim

13, wherein said elongated head has a substantially uniform cross-section.

15. An attachment assembly as defined in claim 10, wherein said through bore is circumscribed by a wall, and wherein said cap is provided with a peripheral seal adapted to sealingly engage said wall .

16. An attachment assembly as defined in claim 9, further including loosening indication means for providing visual indication of eventual loosening of said fixation member.

17. An attachment assembly as defined in claim in claim 16, wherein said loosening indication means include first and second reference marks respectively provided on said dental implant .abutment adjacent said through bore thereof and a cap non-rotatably mounted on said elongated head to close said through bore .

18. A fixation member in combination with a dental prosthesis abutment adapted to be secured to an implant inserted in a patient's jawbone for supporting a dental prosthesis, said fixation member comprising a threaded shank portion adapted to extend through a through bore defined in said dental prosthesis abutment for threadably engaging an implant in order to securely fasten said dental prosthesis abutment to the implant, and an elongated head having opposed proximal and distal ends, said distal end being displaceable between a first position wherein said distal end is located outwardly of said through bore at a distance from a top surface thereof even when said fixation member has been fully tightened, thereby facilitating screwing of said fixation member, and a second position wherein a selected length of said elongated head has been cut off so that said distal end be substantially flush with said top surface of said through bore.

19. A threaded fastener in combination with a dental prosthesis abutment adapted to be secured to an implant mounted in a patient's jawbone, said threaded fastener comprising a threaded shank portion adapted to extend through a through bore of said dental prosthesis abutment for threadably engaging the implant, and an elongated head engageable by a driving tool for allowing said threaded fastener to be screwed into the implant, said elongated head having a distal end portion of substantially uniform cross-section sized to extend outwardly of said through bore to facilitate screwing of said threaded fastener into the implant and adapted to be subsequently transversally cut at a desired location therealong after the threaded fastener has been fully tightened so that said distal end portion be recessed in the fastener receiving opening of the dental prosthesis abutment.