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BACKGROUND OF THE INVENTION
The invention is directed to a system for bracing dental implants or
natural tooth roots to secure artificial teeth and an implantation method
associated therewith.
A common implant system utilizes a bar which is secured to implant heads by
screw-retained sockets. Clips or riders carried by a denture snap-secure
the denture to the bar to allow the denture to be snapped in and out of a
patient's mouth. U.S. Pat. No. 4,516,937 in the name of Hans Bosker is
exemplary of this type of implant system.
U.S. Pat. No. 3,514,858 in the name of Ralph Silverman discloses another
implant system in which a plurality of implant screws have releasably
snap-secured thereto cap members which are bridged by a metal rod or bar.
Several teeth of the denture are hollowed to conform to and seat upon the
cap members thereby holding the denture in place in a patient's mouth.
U.S. Pat. No. 4,713,003 in the name of John M. Symington et al. discloses a
dental implant for connecting an artificial tooth or a dental bridge to a
person's jaw. The dental implant includes a tapered threaded implant body,
an abutment or head keyed nonrotatably thereto, a connecting screw for
coupling the implant body to the head and a retaining screw. A single
tooth or a plurality of teeth can be anchored in the jaw of a patient by
snapping recesses in the tooth or denture upon the implant abutment or
head. In the case of a plurality of artificial teeth forming the denture,
the complement of teeth are secured to each other in an integral fashion
through a metal framework which is then connected to the abutment or head
by a retaining screw which is inserted into the head through a bore of the
associated artificial tooth. The bore in each tooth so affixed to the rod
or metal framework is then filled with a plastic to provide a suitable
surface on the tooth.
Other typical dental implants and associated accessories are far too
numerous to describe in detail, but further typical examples can be found
in the following U.S. patents and the patents cited therein, namely,
Philippe Lonca (U.S. Pat. No. 4,722,688), David B. Rosen (U.S. Pat. No.
5,082,442), Stanley E. Ross (U.S. Pat. No. 4,738,619) and Leonard I.
Linkow (U.S. Pat. No. 4,531,917).
SUMMARY OF THE INVENTION
Pursuant to the present invention, a novel dental implant system is
provided which is less time consuming, less laborious, and less expensive
than conventional implant systems. Custom laboratory design/fabrication is
essentially eliminated because a novel implant head which is constructed
to precision mate with both the implant, implant member, or tooth root on
the one hand and a denture retention bar on the other which carries
conventional clips or riders. The implant heads are supplied in various
axial lengths, and each includes a slot having a bottom portion of a
convex curvature which assures precise location of the attachment bar
relative to a patient's gingiva/gum. The different axial lengths/heights
of the implant heads assures that the base or bottom portion of each slot
of each implant head is precisely located along the crest of the
gingiva/gum, irrespective of irregularities in the latter and, of course,
different depths of implant of the individual implant members. In this
fashion, the attachment bar or rod which is firmly seated in each slot of
each implant head and is appropriately contoured to the gum and/or jaw
line is located a precise minimal distance above the gingiva/gum
(preferably 1 mm), and this assures accurate location of the denture and
excellent underlying support therefor when the denture is subject to high
forces/stresses during mastication/chewing. Thus, by selecting implant
heads of precise heights and bending/contouring the attachment bar at
chairside, a dentist can effect implants, even nonparallel implants up to
25.degree., in a highly efficient and cost-effective manner.
With the above and other objects in view that will hereinafter appear, the
nature of the invention will be more clearly understood by reference to
the following detailed description, the appended claims and the several
views illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded view of a novel dental implant system of the present
invention, and illustrates a plurality of implants supporting an
attachment bar and a denture carrying clips or riders for removably
securing the denture to the attachment bar.
FIG. 2 is an enlarged perspective view of the system of FIG. 1, and
illustrates a portion of the attachment bar and one of the implants of
FIG. 1 which is defined by an implant member, an implant head, an implant
head fastener and an attachment bar fastener.
FIG. 3 is a fragmentary cross-sectional view of a jawbone and gingiva, and
in side elevation illustrates one of the implants and the attachment bar
supported thereby slightly above a ridge or crest of the gum.
FIG. 4 is a slightly enlarged axially cross-sectional view taken generally
along line 4--4 of FIG. 3, and illustrates components of the dental
implant system in relative assembled relationship.
FIG. 5 is a cross-sectional view taken generally along line 5--5 of FIG. 2,
and illustrates a convex bottom of a upwardly opening slot of the implant
head upon which rests a portion of the attachment bar.
FIG. 6 is an enlarged fragmentary cross-sectional view through the denture
and dental implant system of FIG. 1 after the two have been secured
together, and illustrates the manner in which each of the clips or riders
is snap secured to a portion of the attachment bar.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A novel dental implant system is fully illustrated in FIG. 1 of the
drawings and is generally designated by the reference numeral 10. The
dental implant system 10 includes a plurality of implants 11 between which
and to which is secured an attachment bar or rod 12 and a denture 13
defined by a base support 14 carrying a plurality of teeth 15. The base
support 14 has a concave undersurface 16 (FIG. 6) into which projects a
plurality of resilient bifurcated generally C-shaped clips or riders 17.
In FIG. 1 the dental implant system 10 is shown associated with a lower
mouth M of a patient or denture wearer and, as shown in both FIGS. 1 and
2, the mouth M includes a gingiva or gum G having an uppermost surface,
crest or ridge C and an underlying jawbone J which, though not
illustrated, includes an outermost hard bone layer and an inboard mesh
bone layer. The base support 14 of the denture 13 essentially embraces the
gingiva/gum G in the manner schematically illustrated in FIG. 6.
Reference is made specifically to FIGS. 2 through 5 of the drawings in
which each of the implants 11 is shown defined by an implant member 20,
and implant head 30, an implant head fastener 40, and attachment bar
fastener 50, and an optional attachment bar gripping plug 60 (FIG. 4). The
implant member 20, the implant head 30, the implant head fastener 40 and
the attachment bar fastener 50 are all constructed from metallic material,
such as a titanium alloy, a gold/platinum alloy or the like while the
attachment bar gripping plug 60 is a generally cylindrical piece of
polyethylene or similar inert polymeric/copolymeric material.
The implant member or endodontic post 20 is essentially a cylindrical
elongated post or stem having an external thread 21 along its length,
including a conical tip portion or tip 22 thereof which includes a short
channel 23 and a through opening 24. An upper end portion 25 (FIG. 4) of
the implant member 20 is defined by a frusto-conical outer surface 26, a
cylindrical surface 27, an annular shoulder 28 disposed normal to the
central or longitudinal axis (unnumbered) of the implant member 20, and a
hexagonal portion 70 projecting axially upwardly from the annular shoulder
28 and being defined by a plurality of flats 71 (FIG. 2). The hexagonal
portion 70 includes an end face 72 through which opens a threaded bore 73
having a blind end 74. The external thread or threaded portion 21 of the
implant member 20 is conventionally fastened/secured by the threads or
serration within a bore B (FIGS. 3 and 4) formed in the jawbone J of a
predetermined diameter and depth. An appropriate tool (not shown) is
positioned upon the flats 71 of the hexagonal portions 70 of the implant
member 20 to seat the same appropriately in the bore B. The depth of the
implant member 20 is such as to maintain the distance from the annular
shoulder 28 to the crest C of the gum G at an absolute minimum with this
distance being designated by the reference character C/S in FIGS. 3 and 4.
By maintaining the distance C/S at a minimum, the axial height of the head
30 associated therewith can also be held to a minimum which in turn
assures that the denture 13 is positioned as intimately close to the crest
C of the gum G (FIG. 6) as is possible when the clips 17 are secured to
the attachment bar or rod 12, as will be described further hereinafter.
The implant head 30 is generally of a tubular configuration and includes a
lower annular end face 31 defining an end of a relatively large lower
cylindrical portion 32 and adjacent thereto an upper cylindrical end
portion 33 having an upper annular end face 34. The upper cylindrical end
portion 33 has an external thread 35. A central bore 36 extends between
the end faces 31, 34 and is interrupted at the larger lower cylindrical
end portion 32 by a radially inwardly directed annular shelf or rib 37.
Recess means in the form of a generally upwardly opening U-shaped slot 38
is formed in the entirety of the upper cylindrical end portion 33 and
partially in the larger lower cylindrical end portion 32 with a bottom
portion or blind bottom end 39 (FIG. 5) of the slot 38 being of a
generally upwardly convex configuration and setting-off an angle A of
approximately 15.degree. relative to the axis (unnumbered) of the
attachment bar 12 seated thereupon. Diametrically opposite bores 76 (FIGS.
4 and 5) are formed in the larger cylindrical portion 32 for the receipt
of a tool for holding the implant head 30 in any desired position incident
to fixing such a position relative to the implant member 20 by tightening
the implant head fastener 40, as will be described further hereinafter.
The implant head fastener 40 includes a threaded stem 41 which is
complementary to the threaded bore 73 of the implant member 20 and has a
cylindrical head 42 whose exterior diameter is slightly less than the
diameter of the cylindrical bore 36 of the implant head 30. A polygonal
blind recess or slot 43 is formed in the head 42 into which a tool, such
as an Allan wrench or screwdriver, can be inserted for tightening or
loosening the implant head fastener 40.
As is best illustrated in FIG. 4, the axial height of the implant head 30
is so selected that an apex or highest point of the convex bottom 39 (FIG.
5) is in a plane P (FIGS. 3 and 4) which is only very slightly above (1
mm) the crest C of the gum G. In other words, the distance C/S between the
shoulder 28 and the crest C at the gum G is established by selecting an
implant head 30 with an axial distance between its lower annular end face
31 and a crest 90 of the convex bottom 39 of the U-shaped slot 38 such as
will position the lowest surface of the attachment bar 12 1 mm above the
gum crest C, as is illustrated in FIGS. 3 and 4 of the drawings. This
assures the intimate attachment of the denture 13 to the attachment bar
12, as earlier described and shown in FIG. 6.
As is most apparent from FIG. 1, since each patient's jaw J is distinctive,
each of the implants 11 are positioned at different points along the jaw
but because of the ability of selecting implant heads 30 of different
heights, the attachment bar 12 will be located generally a constant 1 mm
from the crest C at the gum G anywhere along the length of the gum G.
Obviously, the implant heads 30 are necessarily first rotated relative to
the implant members 20 and then locked in the desired positions by the
implant head fasteners 40 to secure the attachment bar 12 to the jaw J.
Also, the attachment bar 12 can be, of course, suitably bent, as shown in
FIG. 1, so that portions thereof are readily positioned within each of the
U-shaped slots 38.
After the attachment bar or rod 12 has been bent/conformed as need be to
seat properly in the slots 38 of the implant head 30, the relatively
stiff, though somewhat resilient attachment bar gripping plug 60 (FIG. 4),
is inserted into the cylindrical bore 36. The plug 60 is of an exterior
cylindrical diameter corresponding generally to that of the bore 36 and
the axial height of the plug 60 is slightly (1/10,000") greater than the
distance between the uppermost surface of the attachment bar 12 when
seated in the slot 38 in intimate engagement with the crest 90 of the
bottom convex surface 39 and the upper end face 34 of the implant head 30.
Stated otherwise, when the plug 60 is inserted in the bore 36, an upper
edge portion thereof (unnumbered) projects axially upwardly above the
upper annular end face 34 of the implant head 30 approximately 1/10,000".
Thus, when a force is applied in the downward direction, as viewed in FIG.
4, by the securement of the attachment bar fastener 50 to the implant head
30, each portion of the attachment bar 12 within its associated U-shaped
slot 38 will be brought into intimate bearing engagement with the crest 90
of the bottom convex surface 39 of the slot 38.
The attachment bar fastener 50 is simply a cap nut having an end wall
(unnumbered) and a peripheral skirt 52 having exterior flats 53 and
interior threads 54 which can be threaded upon the threads 35 of the
implant head 30 in the manner clearly illustrated in FIG. 4.
The gripping plug 60 is optional and need not be necessarily utilized with
any one or all of the implants 11 and, if eliminated, a lowermost annular
face 55 of the peripheral skirt 52 will bear against an uppermost surface
(unnumbered) of the attachment bar 12 to thereby force the same into
clamping contact against and in association with the crest 90 of the
bottom convex surface 39 of the U-shaped slot 38 of each of the implant
heads 30, as is readily apparent from FIGS. 3 and 4 of the drawings.
Once the attachment bar 12 is rigidly secured to each of the implants 11,
as shown in FIG. 1, the denture 13 is simply snap-secured to the
attachment bar 12 by the clips/riders 17, in the manner clearly
illustrated in FIG. 6, and removal of the denture 13 is, obviously,
equally readily effected by an upward lifting force applied thereto.
While the dental implant system 10 has been described with respect to the
implants 11 being secured in the jawbone J of a patient, obviously, the
implants 11 can be implanted in tooth roots by simply reducing the crown
of the tooth to the gum line, utilizing a pilot drill and a counterbore
drill to size the tooth roots to accept an implant member 20 of a
particular length/height, post diameter and head diameter. Furthermore,
since tooth roots vary in their angularity relative to the jawbone, it is
within the scope of the present invention to provide implants in which the
axis of the endodontic post 21 is other than coincident to the axis of the
upper end portion 25 or the threaded bore 73 and can, for example, vary at
angles ranging upwardly from 0.degree. to and beyond 25.degree.. Thus, if
a particular tooth root and the pilot bore formed therein was disposed at
15.degree. to the nominal horizontal plane of the gum crest C, an implant
11 would be selected in which the post 21 was offset by a like number of
degrees (15.degree.) from the upper end portion 25, and once implanted,
the axis of the upper portion 25 and the implant head 30 secured thereto
would be disposed generally normal to a horizontal plane through the
nominal crest C of the gum G. Thus, by varying the angles of the upper end
portions 25 of various implants 11 relative to the posts 21 thereof, all
of the U-shaped slots 38 would open generally in a nominal vertical plane
which would further assure accurate location of the attachment bar 12 and
precision unification of the denture 13 relative thereto.
The implant member 20 is a preferred embodiment of the invention, but it is
to be understood that the implant member is only one of a variety of
different designs capable of being used with the implant head 30. There
are a variety of different implant members 20 presently on the market and
might, for example, be longer or shorter than that illustrated, can have a
threaded exterior surface, etc. Furthermore, the implant member 20 and the
implant head 30 can be of an integral one-piece construction in which case
the implant head fastener 40 is, obviously, not required in those
constructions in which the implant member 20 and the implant head 30 are
of an integral one-piece construction, the implant member 20 and
specifically the post 21 thereof is of a relatively small diameter so that
the post 21 can be inserted into a tooth root. Furthermore, where the
implant member 20 and the implant head 30 are of a one-piece integral
construction, the axis of each can be coincident or can vary from
0.degree. to and beyond 25.degree. with the specific angle being selected
such that the axis of the implant head 30 would be disposed generally
normal to a horizontal plane through the nominal crest C of the gum G. As
in the earlier example, if the tooth root and the pilot bore formed
therein was disposed at 15.degree. to the nominal horizontal plane of the
gum crest C, the post 21 would be offset by 15.degree. relative to the
axis of its integral implant head 30. In addition, though the length of
the post 21 can vary, be it separately connectable to or integral with the
implant head 30, the post can be appropriately cut to length for insertion
into a jaw or bored tooth root.
Although a preferred embodiment of the invention has been specifically
illustrated and described herein, it is to be understood that minor
variations may be made in the apparatus without departing from the spirit
and scope of the invention, as defined in the appended claims.
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