 |
Claims  |
|
|
We claim:
1. A device for forming a dental prothesis comprising:
a cap defining an inner space;
a support for supporting the cap, the cap and the support having a common,
first axis; and
a screw for fastening the cap on the support,
wherein the support has an inner end for being inserted in a jawbone of a
dental prothesis user, and an outer part to be located outside of the
jawbone for supporting the cap, the outer part having a bearing surface
cooperating with a counter bearing surface of the cap in an assembled
condition of the device,
wherein the cap has a threaded hole for receiving the fastening screw and
opening into the inner space, the hole having a second axis extending at
an angle to the first axis, and
wherein the screw has a tapering end section extending, at least partially,
into the inner space and engaging a shoulder, which is provided on the
outer part and faces the inner part, for generating a pressure force for
pressing the counter bearing surface of the cap against the bearing
surface of the outer part.
2. A device according to claim 1, wherein the shoulder is annular and
extends along a circumference of the outer part.
3. A device according to claim 1, wherein the shoulder has an outer border
engageable by the screw end section.
4. A device according to claim 1, wherein the screw is formed of a material
which is harder than a material forming the shoulder.
5. A device according to claim 1, wherein the cap has a solid end section
remote from the support.
6. A device according to claim 1, wherein the second axis extends outwardly
of the support and forms with the first axis an angle between 30.degree.
and 90.degree..
7. A device according to claim 1, wherein the bearing surface of the
support and the counter bearing surface of the cap are conical and are
inclined outwardly toward the inner end of the support.
8. A device according to claim 1 wherein the support includes:
an elongate one-piece base having a first end defining the inner end of the
support, an outer end opposite the inner end, and a hole formed in the
outer end and having a section with an inner thread; and
a holder having a inner portion receivable in the base hole and provided
with an outer thread cooperating with the inner thread of the base hole,
and an outer portion for projecting from the base hole.
9. A device according to claim 8, wherein the base hole has a conical
section with an outwardly inclined conical surface extending between the
section with an inner thread and a mouth of the hole, and the holder has a
conical surface bearing against the conical surface of the base hole.
10. A device according to claim 9, wherein the holder comprises a first
one-piece part having a head defining the outer portion of the holder and
having circumferential surface sections which are non-rotationally
symmetrical relatively to the first axis.
11. A device according to claim 10, wherein the first part has an axial
threaded bore extending up to an end surface of the head, and wherein the
holder further comprises a second one-piece part having a threaded
portion, receivable in the axial threaded bore of the first part, and a
holding portion projecting out of the head of the first part and having an
annular groove defining the outer part shoulder.
12. A device according to claim 10, wherein the cap has inner surface
sections, which are non-rotationally symmetrical relative to the first
axis, for engaging the circumferential surface sections of the head.
13. A device according to claim 10, wherein the base has conical annular
surface surrounding a mouth of the base hole and inclined outwardly
relative to the first end;
wherein the holder comprises a second part having a conical annular surface
for bearing against the conical annular surface of the base, an annular
groove defining the outer part shoulder, and an axial hole; and wherein
the device further comprises a screw extendable through the axial bore of
the second part and receivable in the axial threaded bore of the first
part for connecting the second part with the first part.
14. A device according to claim 9, wherein the base has a conical annular
surface surrounding a mouth of the base hole and inclined outwardly
relative to the first end; wherein the holder includes a first, one-piece
part defining the inner and outer portions of the holder, the outer
portion having an annular groove defining the outer part shoulder, a
conical annular surface for bearing against the conical annular surface of
the base, and a conical outer surface tapering away from the inner portion
and forming a smaller angle with the first axis than the conical annular
surface thereof; and wherein the holder further includes a second part
formed as a sleeve having a conical surface defining the conical surface
of the holder bearing against the conical surface of the base hole, and an
axial hole having an internal thread, the outer thread of the inner
portion cooperating with the internal thread of the sleeve axial hole when
the inner portion is received in the base hole.
15. A device according to claim 14, wherein the second part has a conical
outer surface defining the bearing surface of the outer part.
16. A device according to claim 8, wherein the base has a conical annular
surface surrounding a mouth of the base hole, inclined outwardly relative
to the first end and defining the bearing surface of the outer part.
17. A device according to claim 1, wherein the cap is formed of titanium.
18. A device according to claim 17, further comprising a titanium member
for supporting an artificial tooth and laser-weldable to the cap.
19. A device according to claim 1, comprising a sleeve formed of burnable
material and fastened on the cap, and a metal bushing supported in the cap
and forming the threaded hole of the cap.
20. A method of manufacturing a device for forming a dental prothesis,
comprising the steps of:
providing a cap defining an inner space;
providing a support for supporting the cap; and
providing a screw for fastening the cap on the support,
wherein the support providing step includes providing a support having an
inner end for being inserted in a jawbone of a dental prothesis user, and
an outer part to be located outside of the jawbone for supporting the cap
and having a bearing surface for cooperating with a counter bearing
surface of the cap in an assembled condition of the device,
wherein the cap providing step includes providing a cap having a threaded
hole for receiving the fastening screw and opening into the inner space
and defining a second axis extending at an angle to a first, common axis
of the support and the cap; and
wherein the screw providing step includes providing a screw having a
tapering end section for extending, at least partially, into the inner
space and for engaging a shoulder, which is provided on the outer part and
faces the inner part, for generating a pressure force for pressing the
counter bearing surface of the cap against the bearing surface of the
outer part.
21. A method according to claim 20, wherein the cap providing step include
manufacturing the cap from titanium.
22. A method according to claim 21, wherein the cap providing step further
includes laser welding of a titanium element for supporting an artificial
tooth to the cap.
23. A method according to claim 20, wherein the cap providing step includes
the steps of:
forming a sleeve of a burnable material;
providing a metal bushing having an axial threaded bore and fastening the
bushing on the sleeve to form a cap, with the threaded bore forming the
threaded hole of the cap;
applying a burnable modelling material on the outside of the cap;
forming a casting mold surrounding the cap and filling an inner space of
the sleeve;
burning the sleeve and the burnable material applied on the outside of the
cap, whereby a hollow inner space is formed in the mold; and
filling the hollow inner space of the mold with a casting material for
producing a cast cap, with the bushing being mounted in the cap. |
|
 |
|
 |
Claims |
|
|
|
Description |
|
|
BACKGROUND OF THE INVENTION
The invention relates to a device for forming a dental prosthesis.
The dental prosthesis can have only one single artificial tooth or only one
artificial dental crown or two or more artificial teeth or dental crowns.
Devices for forming a dental prosthesis known under the ITI mark on the
market have a support and a cap which can be fastened thereon and serves
to form an artificial dental crown. The support has a base or primary part
and a secondary part which can be detachably connected thereto. The base
has a first end, which sits in a hole of a jawbone during the use of the
device, a second end projecting from the jawbone, an axial hole which
opens into this end and has a section with an internal thread. The base
has a conical annular surface which surrounds the mouth of the hole and
which serves as a bearing surface for the cap. The secondary part serves
as a holder for holding the cap and has an inner part which is screwed
into the hole of the base, an octagonal head situated outside the base,
and an axial threaded hole opening into the end face of the head. The cap
consists of a gold alloy and has a conical countersurface which rests on
the conical bearing surface of the base and a hole which is coaxial with
the axis of the support and the countersurface of the cap. The cap is
fastened on the secondary part with a screw which penetrates the hole and
is screwed into the threaded bore of the secondary part. During use of the
device, additional materials are also applied to the originally
approximately frustoconical cap so that, together with the materials
applied, an artificial dental crown having the desired shape is formed.
In these known devices, the hole of the cap opens in the apical end of the
cap facing away from the jawbone. The head of the screw accordingly lies,
in an artificial molar, in or below the masticating surface of the crown
which is in part formed by the cap. In an artificial incisor or canine,
the screw head is situated, for example, below or close next to the
cutting part of the dental crown. The hole of the cap and the screw
therefore hinder optimum formation of the dental crown. This is the case
in particular in incisors. In addition, the screw head is aesthetically
disturbing.
The devices known under the mark ITI are used not only for replacing
individual teeth but also for fastening and/or forming bridges replacing a
number of teeth and in this case have two or more supports, on which a cap
is fastened in each case. A connection element forming at least one
artificial tooth is arranged between these and connected by cast or
soldered connections to the caps which consist of a gold alloy. In order
that the caps can be mounted on the octagonal heads of the supports, the
axes of the two supports must be reasonably accurately parallel with one
another. Accordingly, the holes drilled in the jawbone for receiving the
bases must be reasonably accurately parallel with one another so that
great accuracy is necessary when drilling these holes.
The aim of the invention is to produce a device having at least one support
and at least one cap, which makes it possible to eliminate disadvantages
of the known devices, and in particular to avoid the hole of the cap
having to be coaxial with the axis of the support and the screw serving
for fastening the cap having to have a head lying at the apical end of the
cap.
SUMMARY OF THE INVENTION
The aim of the invention is achieved by providing a device for forming a
dental prothesis in which the secondary part has a shoulder which faces
the end of the support at least when the device has been assembled, the
hole of the cap has an internal thread, the screw axis forms an angle with
the axis of the device, and the screw has an end section tapering away
from its thread and, when the cap is arranged on the secondary part, can
be screwed into the internal thread of the cap in such a manner that the
end section of the screw engages on the shoulder, and thus generates a
force pressing the countersurface of the cap against the bearing surface
of the support.
BRIEF DESCRIPTION OF THE DRAWINGS
The subject of the invention is explained below with reference to exemplary
embodiments illustrated in the drawing, in which
FIG. 1 shows an exploded illustration of parts of a device for fastening
and forming a dental prosthesis with a single artificial tooth,
FIG. 2 shows a view of the cap of the device visible in FIG. 1 from below,
FIG. 3 shows a section through a jawbone and parts of the device visible in
FIG. 1,
FIG. 4 shows a section through the jawbone and, fastened thereon, the
device with a finished, artificial dental crown,
FIG. 5 shows a section through a jawbone and another device fastened
thereon,
FIG. 6 shows a section through a jaw model of one and parts of another
device, the cap of which has a sleeve made of plastic,
FIG. 7 shows a section through a casting mould which surrounds the cap
visible in FIG. 6,
FIG. 8 shows a section through a jawbone and, fastened thereon, a device
with a cast cap,
FIG. 9 shows a section transversely through a jawbone and through the axis
of a support of, fastened thereon, a device with a bridge,
FIG. 10 shows a longitudinal section through a piece of the jawbone visible
in FIG. 9 and through the bridge fastened thereon,
FIG. 11 shows a section through a jaw model of one and through parts of
another device which is fastened thereon and serves for forming a bridge,
FIG. 12 shows a section through a device manufactured with the aid of the
parts illustrated in FIG. 11, and
FIG. 13 shows a section through a jawbone and yet another device fastened
thereon.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The device which is shown in FIG. 1 in dismantled state and in FIG. 4 in
the assembled end state and is designated as a whole by 1 serves for
fastening and forming a dental prosthesis, namely a single artificial
tooth. The device 1 has a support 3 with a base 4, frequently also
designated as primary part or implant, and a holder 5 which consists of a
secondary part 6 and a tertiary part 7. The device 1 also has a cap 8
which, with the aid of a screw 9, can be connected rigidly and detachably
to the support 3. The three parts 4, 6, 7 of the support 3 and the cap 8
define in the assembled state a common, first axis 10.
Some parts of the device 1 are also visible in FIGS. 2 and 3. Furthermore,
in FIGS. 3 and 4, a jawbone 13--namely a lower jawbone--and the gingiva 14
--i.e. the gum--covering the jawbone of a patient are also drawn. The
support 3 has an inner part 3a which in the end state of the device 1 is
situated inside the jawbone 13 and an outer part 3b situated outside the
jawbone 13.
The elongate, one-piece base 4 has a first end 4a which is situated at the
bottom in FIG. 1, and, facing away from this, a second end 4b. The shell
surface of the base has a generally cylindrical main section 4c with an
external thread 4d and an end section 4e which widens in a trumpet-shaped
manner towards the second end 4b. The base has two axial blind holes,
namely one hole 4f opening into its first end 4a and one hole 4g opening
into its second end 4b. The hole 4g has a cylindrical section 4h with an
internal thread 4i and, widening from this towards the second end 4b of
the base 4, a section 4k with a cone surface 4m. This forms with the axis
10 an angle amounting to 5.degree. to 15.degree. and for example
approximately 8.degree.. The base has at its second end 4b a conical
annular surface 4n which surrounds the mouth of the hole 4g and the axis
10 completely and continuously, is rotationally symmetrical in relation to
the axis 10, is inclined outwards towards the first end 4a of the base and
forms with the axis 10 an angle of approximately or exactly 45.degree.. As
will be explained in greater detail, the conical annular surface 4n also
serves, in the variant embodiment of the device drawn in FIG. 1, as a
bearing surface 4n for the cap 8. Furthermore, the base also has some
radial holes 4p which open into the axial hole 4f.
The one-piece secondary part 6 has an inner part 6a which has an external
thread 6b and also, widening away from this, a cone surface 6c which forms
the same angle with the axis 10 as the cone surface 4m. When, according to
FIG. 4, the secondary part 6 is connected to the base 4, the inner part 6a
of the secondary part 6 is situated in the hole 4g of the base 4, the
external thread 6b being screwed into the internal thread 4i and the cone
surfaces 4m and 6c bearing firmly against one another. The secondary part
6 has a head 6d which is situated outside the base 4 when the device 1 has
been assembled. This head has a section 6e with a polygonal
circumferential surface 6f which is non-rotationally symmetrical in
relation to the axis 10 and for example forms in cross-section a regular
octagon. This surface accordingly has several, namely eight, plane,
circumferential surface sections which are non-rotationally symmetrical in
relation to the axis 10 and eight edges parallel to the axis 10. The head
6d also has a conical chamfer 6g which tapers from the circumferential
surface 6f towards the end side 6h of the head. The end side 6h of the
head 6d forms the outer end of the secondary part, which faces away from
the inner part 6a of the secondary part 6. The secondary part 6 is
provided with an axial threaded bore 6i which opens into the end face 6h.
The one-piece tertiary part 7 has a bolt-shaped threaded part 7a which is
provided with an external thread and is screwed into the threaded bore 6i
of the secondary part 6 when the device 1 has been assembled. The tertiary
part 7 also has a holding section 7b, which is situated outside the
secondary part 6 when the device has been assembled, with a collar which
bears with a plane, radial annular surface on a radial, plane annular
surface present on the end side 6h of the head 6d. The holding section 7b
also has a neck projecting away upwards from the collar and a head 7c. The
collar, neck and head 7c together delimit an annular groove 7d surrounding
the axis 10. The head 7c has a radial, plane surface adjoining the annular
groove 7d and forming the upper flank thereof, a cylindrical
circumferential surface and a transition surface which connects the
radial, plane surface to the cylindrical circumferential surface and is
convexly curved in axial section. The side of the head 7c adjoining the
annular groove 7d forms an annular shoulder 7e which runs along the
circumference of the support outer part 3b and the outer border 7f of
which is formed by the transition surface which is curved in axial
section. The shoulder 7e faces the base 4 and its second end 4b when the
device 1 has been assembled. The transition surface forming the outer
border 7f of the shoulder 7e has in axial section a radius of curvature
which amounts to 0.5 mm at most, preferably 0.3 mm at most and for example
approximately 0.2 mm. It is to be noted that, instead of the curved
transition surface or if appropriate in addition to this, the outer border
7f of the shoulder 7e could have an edge. The head of the tertiary part 7
has a polygonal and/or star-shaped hole 7g opening into its end side.
The one-piece cap 8, which is also shown separately in FIG. 2, has a shell
8a and a compact, apical end section 8b which is hole-free in particular
in the region of the axis 10 and faces away from the base 4 when the
device 1 has been assembled. The cap 8 is generally rotationally
symmetrical in relation to the axis 10 but has a nose 8c which projects to
the right in FIGS. 1, 2 and 4. The cap 8 has an inner surface 8d which
delimits an inner space 8e which is generally rotationally symmetrical in
relation to the axis 10 and open towards the base 4. The section of the
inner surface 8d adjoining the mouth of the inner space 8e forms a conical
countersurface 8f which is inclined away from the mouth towards the axis
10, surrounds the axis 10 completely and continuously, forms with this the
same angle as the annular and/or bearing surface 4n of the base 4 and
bears against the conical annular and/or bearing surface 4n when the
device has been assembled. The two conical surfaces 4n and 8f have
external diameters of the same size so that the outer and/or shell
surfaces of the base 4 and of the cap 8 abut at the outer borders of the
conical surfaces 4n and 8f when the device 1 has been assembled. The inner
surface 8d has, on the side of the countersurface 8f facing away from the
mouth of the inner space 8e, a polygonal inner surface region 8g which is
non-rotationally symmetrical in relation to the axis 10 and for example
24-cornered in cross-section. This region therefore has several, namely
24, plane, non-rotationally symmetrical surface sections parallel to the
axis 10 and 24 corners or edges parallel to the axis 10. In FIG. 2, the
outline of the head 6d is also indicated in dot-dash lines. This is
designed in such a manner that the corners of its octagonal section 6e
engage snugly or with at most small radial play in corners of the
24-cornered inner surface region 8g. The inner surface 8d has, above the
24-cornered inner surface region 8g, a cylindrical inner surface section
8h, which is adjoined by a likewise cylindrical, slightly narrower inner
surface section 8i. The diameter of the latter is at most slightly greater
than the diameter of the head 7c of the tertiary part 7. When the cap 8 is
pushed onto the support 3 parallel to the axis 10 during assembly of the
device 1, it is guided axially displaceably and radially at least
approximately without play by the heads 6d and 7c of the secondary part 6
and tertiary part 7 respectively. The surface sections and the edges of
the circumferential surface 6f which is non-rotationally symmetrical in
relation to the axis 10 and of the inner surface region 8g form in
addition securing means which secure the cap 8 against rotations with
regard to the secondary part 6 of the support 3 when the device has been
assembled. When the device 1 has been assembled, according to FIG. 4, an
interspace is present between the end surface of the head 7c of the
tertiary part 7 and the inner surface section of the cap 8 delimiting the
upper end of the inner space 8e. The cap 8 has a hole 8k which extends
through the nose 8c into the inner space 8e and the outer mouth of which
lies in a surface of the nose 8c which is inclined in relation to the axis
10 and the inner mouth of which lies mainly in the region of the
cylindrical inner surface section 8h of the cap. The hole 8k is provided
with an internal thread 8m. The hole 8k surrounds and defines a second
axis 11. The hole 8k and the section of the axis 11 situated in it are
inclined away upwards from the axis 10 and thus away from the base 4. The
second axis 11 forms with the first axis 10 an angle which amounts to at
least 30.degree., preferably at least 45.degree., less than 90.degree.,
for example 55.degree. to 85.degree. and namely according to FIGS. 1, 4
approximately 65.degree.. The hole 8k and the screw 9 screwed into it when
the device 1 has been assembled are thus to a greater or lesser extent
transverse to the axis 10.
The screw 9 has a thread 9a and, tapering away from this, a for example
approximately frustoconical end section 9b. The conical surface of the
latter forms with the screw axis, which coincides with the axis 11 of the
hole 8i when the device 1 has been assembled, an angle which amounts to at
most 60.degree., preferably at most 45.degree. and for example
approximately 30.degree.. The screw 9 is designed as a headless screw and
thus has no head so that the nominal or external diameter of its thread 9a
forms the maximum diameter of the screw 9. This has, at its end facing
away from the end section 9b, a hole 9c which has a polygonal, for example
hexagonal, section, the surfaces and edges of which form driving means for
a screwing-in tool. The nominal or external diameter of the thread 9a
amounts preferably to at least 1.5 mm and for example approximately or
exactly 2 mm. The overall length of the screw 9 is at most three times and
for example approximately twice the size of the nominal or external
diameter of the thread 9a.
When the device 1 has been assembled, the screw 9 is according to FIG. 4
screwed into the hole 8k of the cap 8 in such a manner that the conical
surface of the end section 9b of the screw 9 engages on the outer border
7f of the shoulder 7e of the tertiary part 7. At its point touching the
shoulder 7e, the conical surface of the screw 9 forms with the axis 10 an
angle which amounts to preferably at least 30.degree., preferably at most
60.degree. and for example according to FIG. 4 approximately 35.degree..
When the screw 9 has been screwed in firmly, the shoulder 7e of the
tertiary part 7 exerts a force on the screw and via this on the cap 8.
This force has a component which is parallel to the axis 10 and which
presses the countersurface 8f of the cap 8 against the bearing surface 4n
of the base 4 and clamps the cap 8 firmly on the support 3. The screw 9 is
situated completely inside the cap 8 when the device 1 has been assembled
and finished.
The base 4, secondary part 6, tertiary part 7, the cap 8 and the screw 9
consist of biocompatible metal materials. The base 4, the secondary part 6
and the tertiary part 7 and the cap 8 consist for example of pure
titanium. The outer surface of the cylindrical main section 4c of the base
4 can be formed by a porous coating likewise consisting of titanium which
is applied by plasma spraying. The screw 9 is formed for example from an
alloy consisting mainly of titanium and is harder than the cap 8. When the
screw 9 is tightened during assembly of the device 1, the screw 9 can
produce an indentation in the outer border 7f of the shoulder 7e. This
indentation secures the cap 8 in addition to the polygonal circumferential
surface 6f of the secondary part 6, which engages on the polygonal inner
surface region 8g, against rotations with regard to the support 3.
The manufacture, use and also the assembly of the device 1 in the fastening
and formation of an artificial dental prosthesis are now also to be
explained. First, the parts of the device 1 drawn in FIG. 1 are
manufactured in a manufacturing factory and supplied, for example in
demounted state, to a dentist and/or dental technician.
If the dentist wishes to use the device 1 in the treatment of a patient,
the dentist can cut open the gingiva 14 of the patient, drill and/or mill
a hole 13a into the jawbone 13, screw the base 4 into this and close the
upper axial hole 4g of the latter with a closure screw (not shown) screwed
into it. The base 4 can then remain in the jawbone 13 for a taking period
until the jawbone has healed. The bone can subsequently fill the lower
axial hole 4f and also penetrate the radial holes 4p so that the base is
anchored vary stably in the jawbone 13.
After the taking period, the dentist can unscrew the closure screw from the
base 4, screw the secondary part 6 into the latter and fasten an
impression cap 15, indicated in dot-dash lines in FIG. 3, on the secondary
part 6. The dentist can then make an impression with a plastically
deformable material which is pressed onto the jaw, onto the impression cap
15 and onto the teeth adjacent to the latter with a so-called tray.
A dental technician can then produce a model of a jawbone from plaster or
the like and provide it with a handling support which is of the same
design as the handling support 43 drawn in FIG. 6 which serves for forming
another device and is described in greater detail. The dental technician
can fasten the cap 8 on the handling support and bring the cap 8 into a
desired shape on the basis of the impression by material-removing
finishing--i.e. by milling and/or grinding. The original outline shape and
the outline shape of the cap 8 existing after finishing are shown in FIG.
4 with dot-dash and solid lines respectively. It is to be noted that the
section of the nose 8c delimiting the outer mouth of the hole 8k is drawn
in FIG. 4 with the original shape but if necessary can also be further
worked, it being possible to mill off and/or grind off a section of the
screw 9 as well. The dental technician can also provide the outer surface
of the cap 8 partially with a veneer 16 which can be seen in FIG. 4 and
consists for example of ceramic (porcelain) or plastic. The cap 8 then
forms together with the veneer 16 a supraconstruction 17, namely an
artificial dental crown.
The secondary part 6, which is connected to the jawbone 13 of the patient
by the implant 4, can be closed for example with a closure element during
the working of the cap 8 to form a supraconstruction 17 or artificial
crown. When the crown is finished, the dentist can first screw the
tertiary part 7 into the secondary part 6.
The cylindrical main section 4c of the base 4 and the lower end section of
the secondary part 6 then form the inner part 3a of the support 3 situated
in the jawbone 13. The first end 4a of the base 4 forms in this connection
the end of the support 3 situated on the jawbone. Furthermore, the second
end 4b of the base 4, the upper section of the secondary part 6 and the
tertiary part 7 together form the outer part 3b of the support 3 situated
outside the jawbone 13. The end of the support 3 situated outside the
jawbone is formed by the head 7c of the tertiary part 7. The secondary and
the tertiary part together form the holder 5 of the support 3, which
serves for holding the supraconstruction 17 or dental crown.
The dentist can then also mount the supraconstruction 17 or dental crown
formed from the finished cap 8 and the veneer 16, together with the screw
9 which has already been screwed a little into the cap 8, on the outer
part 3b of the support 3, screw the screw 9 firmly with a screwing-in tool
and thus fasten the cap 8 forming the majority of the supraconstruction 17
on the support 3. The dental crown shaped according to FIG. 4 can for
example form together with the remaining parts of the device 1 an
artificial incisor or canine. The finished end section 8b of the cap 8
facing away from the base 4 and the jawbone 13 and the veneer 16 applied
to the end section 8b together form the apical end and the cutting part of
the artificial dental crown. The cutting edge of the cutting part is
situated on the side of the axis 10 facing away from the nose 8c of the
cap 8. Furthermore, the nose 8c, the mouth of the hole 8k lying in this
and thus essentially the entire hole 8k and also the screw 9 are
situated--in relation to the mouth of the patient--on the rear side of the
cap 8 so that the hole 8k and the screw 9 are not visible from the outside
of the mouth. As the hole 8k and the greater are to a greater or lesser
extent transverse to the axis 10, the shape of the apical end, facing away
from the jawbone 13, of the supraconstruction 17 or artificial dental
crown can be favourably established and extensively adapted to the shape
of a natural tooth.
The octagonal circumferential surface region 6f of the secondary part 6 and
the 24-cornered inner surface region 8g of the cap 8 make it possible to
mount the latter optionally in 24 different rotary positions on the
support 3 and to connect it unrotatably thereto. The relatively great
number of selectable rotary positions of the cap 8 makes it possible to
insert it into the mouth of the patient in such a manner that the nose 8c
and the hole 8k are situated in a position which is expedient for screwing
firm the screw 9. As the hole 8k is inclined away from the jawbone in the
direction running away from the axis 10, the dentist can screw the screw 9
firm relatively well although the hole 8k is arranged on the rear side of
the cap 8.
When the device 1 has been assembled according to FIG. 4 and is fastened in
the jawbone 13, the various parts of the support 3, i.e. the base 4, the
secondary part 6 and the tertiary part 7 are stably interconnected. The
support 3 has great strength. The outer part 3b of the support 3 centres
the cap 8 or--more precisely--its inner space 8e in relation to the
support 3 and secures the cap 8 against rotations about the axis 10 also.
The conical countersurface 8f of the cap bearing on the conical bearing
surface 4n of the base 4 likewise has the effect of centring the cap in
relation to the base 4. The cap 8 is connected very stably to the support
3 and can therefore transmit to the support both great forces parallel to
the axis 10 and great forces forming an angle with the axis 10. Because
the screw 9 has a relatively great diameter, is quite short in comparison
with this and engages at a point on the shoulder 7e of the tertiary part 7
situated close to the hole 8k of the cap 8 holding the screw 9, the risk
of the screw 9 breaking is also very low.
As a result of the conical surfaces 4n and 8f which bear on one another and
the shell surfaces of the base 4 and of the cap 8 which abut without a gap
at the outer borders of the conical surfaces, it is additionally
practically completely prevented that cultures of microorganisms develop
between the base 4 and the cap 8. Furthermore, the very good
biocompatibility of titanium is also advantageous.
The device 1 has only relatively few separate parts and can be economically
manufactured and also relatively easily inserted into the mouth of a
patient and assembled. Furthermore, a dental technician can, from the cap
8 consisting of titanium which can be seen in FIG. 1 and is supplied from
the manufacturing factory, manufacture an artificial dental crown adapted
to the individual requirements of a patient with relatively low labour and
material expenditure.
In FIG. 5, a jawbone and a gingiva can be seen, which are again designated
with 13 and 14 respectively. Furthermore, in FIG. 5, an assembled device
21 can be seen, which is fastened on the jawbone 13, situated in its end
state and forms a dental prosthesis serving as an artificial molar. The
device 21 has a support 3 which is of identical design to the support 3 of
the device 1. The support 3 has in particular a base 4, fastened in a hole
13a of the jawbone 13, with a conical annular and bearing surface 4n, and
a holder 5 with a secondary part 6 and a tertiary part 7. The device 21
also has a cap 28 which has a common first axis 10 together with the
support 3 when the device has been assembled. The cap 28 has, like the cap
8, a shell 28a, an end section 28b facing away from the base 4, and a nose
28c projecting away from the shell 28a at a circumferential point thereof.
The cap 28 differs from the cap 8, however, in that its shell 28a is
generally--i.e. apart from the nose 28c--not cylindrical but conical and
tapers away from the base 4. Furthermore, the dimension of the end section
28b of the cap 28 measured parallel to the axis 10 is smaller than in the
cap 8. Furthermore, the cap 28 does not consist of titanium but of a
non-oxidizing metal material which can be cast on, for example a gold
alloy available under the trade name CERAMICOR. The inner surface 28d and
the inner space 28e of the cap 28 delimited by this surface are for
example of the same design as in the cap 8. The inner surface 28d has in
particular at the mouth of the inner space a section which forms a conical
countersurface 28f which bears on the conical bearing surface 4n of the
base when the device 21 has been assembled. The cap 28 also has a hole 28k
which opens into the inner space 28e similarly to the hole 8k, has an
internal thread 28m and defines a second axis 11. Screwed into the hole
28k is a screw 9 which is of the same design as in the device 1 and,
similarly to this case, engages on the outer border 7f of the shoulder 7e
of the tertiary part 7.
The cap 28 is supplied to a dentist and/or dental technician from the
manufacturing factory with the shape drawn in FIG. 5. In the use of the
device 21, a dental technician can apply a carrier layer 35 to regions of
the outer surface of the cap 28. The carrier layer 35, which forms a
so-called supporting structure, can for example consist of a gold alloy
which is cast onto the cap 28 and oxidizes in the presence of oxygen and
onto which a veneer 36 consisting of ceramic or plastic is applied. The
cap 28 then forms together with the carrier layer 35 and the veneer 36 a
supraconstruction 37, namely an artificial dental crown, the apical end of
which, which faces away from the jawbone 13 and base 4, can form for
example the masticating surface of a molar.
The device 21 is--provided nothing else has been indicated previously--of
similar design to the device 1 and also to a great extent has similar
properties to it.
Next, with reference to FIGS. 6, 7 and 8, the manufacture and design of a
device 41 forming an artificial single tooth, which can be seen in the
finished state in FIG. 8, will be described. In FIG. 6, a jaw model 42
consisting for example of plaster can be seen, the upper part of which for
example has approximately the same outline shape as the jawbone, covered
by the gingiva, of a patient. Also drawn in FIG. 6 is a handling support
43 with an inner part 43a situated inside the jaw model 42 and an outer
part 43b situated outside the jaw model. This has a one-piece handling
implant 44 with a base 44a which is fastened in the jaw model 43 and the
upper region of which has the same shape as the upper end section of a
base 4. The lower region of the base of the handling implant 44, which
cannot be seen in FIG. 6, can on the other hand have a different shape
from the corresponding section of the base 4, as is indicated in the
handling implant 44 drawn in FIG. 11 which serves for forming another
device. The handling implant 44 also has a head 44b which is situated
outside the jaw model 43 and has the same shape as the head 6d of a
secondary part 6. The handling implant 44 is additionally provided with a
threaded bore 44c corresponding to the threaded bore 6i of a secondary
part 6. The handling implant has a conical annular and/or bearing surface
44n which is of similar design to the annular and/or bearing surface 4n of
a base 4. The handling support 43 also has a tertiary part 7 screwed
detachably into the threaded bore 44c of the handling implant 44.
In FIG. 8, a jawbone 13 with a hole 13a and the gingiva 14 of a patien | | |
