U.S. patent application number 14/474604 was filed with the patent office on 2015-03-26 for two-part implant with a hydroxylated soft tissue contact surface.
This patent application is currently assigned to STRAUMANN HOLDING AG. The applicant listed for this patent is Jurgen Becker, Michel Dard, Frank Schwarz, Marco Wieland. Invention is credited to Jurgen Becker, Michel Dard, Frank Schwarz, Marco Wieland.
Application Number | 20150086943 14/474604 |
Document ID | / |
Family ID | 36297382 |
Filed Date | 2015-03-26 |
United States Patent
Application |
20150086943 |
Kind Code |
A1 |
Schwarz; Frank ; et
al. |
March 26, 2015 |
TWO-PART IMPLANT WITH A HYDROXYLATED SOFT TISSUE CONTACT
SURFACE
Abstract
Two-part implant for attachment of artificial teeth comprising a
base body having a bone contact surface and a soft tissue contact
surface. The soft tissue contact surface is at least partially
hydroxylated or silanated which results in an improved soft tissue
integration.
Inventors: |
Schwarz; Frank; (Dusseldorf,
DE) ; Becker; Jurgen; (Dusseldorf, DE) ;
Wieland; Marco; (Basel, CH) ; Dard; Michel;
(Liestal, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schwarz; Frank
Becker; Jurgen
Wieland; Marco
Dard; Michel |
Dusseldorf
Dusseldorf
Basel
Liestal |
|
DE
DE
CH
CH |
|
|
Assignee: |
STRAUMANN HOLDING AG
Basel
CH
|
Family ID: |
36297382 |
Appl. No.: |
14/474604 |
Filed: |
September 2, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11680055 |
Feb 28, 2007 |
|
|
|
14474604 |
|
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|
Current U.S.
Class: |
433/174 ;
206/63.5; 216/53; 216/83 |
Current CPC
Class: |
A61C 8/0093 20130101;
A61L 27/50 20130101; A61K 6/30 20200101; A61C 2008/0046 20130101;
A61C 8/0013 20130101; A61L 2430/12 20130101; A61C 8/0012 20130101;
A61C 8/005 20130101; A61C 8/0009 20130101; A61L 2400/18 20130101;
A61C 8/0015 20130101; B65D 85/50 20130101 |
Class at
Publication: |
433/174 ; 216/83;
216/53; 206/63.5 |
International
Class: |
A61C 8/00 20060101
A61C008/00; B65D 85/50 20060101 B65D085/50; A61K 6/00 20060101
A61K006/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 28, 2006 |
EP |
06004063.1 |
Claims
1-19. (canceled)
20. Anchor part of a two-part implant system for attachment of
artificial teeth, the anchor part being made of ceramic and
comprising a base body having a bone contact surface and a soft
tissue contact surface, wherein the soft tissue contact surface is
at least partially hydroxylated.
21. Anchor part according to claim 20, wherein the soft tissue
contact surface is completely hydroxylated.
22. Anchor part according to claim 20, wherein the soft tissue
contact surface is roughened.
23. Anchor part according to claim 20, wherein the soft tissue
contact surface is smooth.
24. Anchor part according to claim 22, wherein the surface
roughness of the soft tissue contact surface increases towards the
bone contact surface continuously or stepwise.
25. Anchor part according to claim 20, wherein the soft tissue
contact surface is hydrophilic.
26. Anchor part according to claim 20, wherein the soft tissue
contact surface has the same macroscopic texture as the bone
contact surface.
27. Anchor part according to claim 20, wherein it is made of
ceramic comprising a zirconium oxide based material.
28. Method for producing an anchor part of a two-part implant
system in accordance with claim 20, wherein the soft tissue contact
surface is treated with a chemical etching procedure until a
hydroxylated surface has been produced.
29. Method according to claim 28, wherein the soft tissue contact
surface is shot-blasted, sandblasted and/or roughened using plasma
technology before treating with the chemical etching procedure.
30. Method according to claim 28, wherein the chemical etching
procedure is carried out with an inorganic acid or a blend of
inorganic acids.
31. Method according to claim 30, wherein said inorganic acid is
selected from the group consisting of hydrofluoric acid,
hydrochloric acid, sulphuric acid and mixtures thereof.
32. Method according to claim 30, wherein said blend of inorganic
acids is hydrochloric acid (conc.), hydrogen peroxide and water in
a weight ratio of approximately 1:1:5.
33. Method according to claim 30, wherein said blend of inorganic
acids is a mixture of hydrochloric acid (conc.)/sulphuric acid
(conc.)/water: 2/1/1.
34. Method according to claim 28, wherein the surface is washed
with pure water, which can additionally comprise additives, in an
atmosphere that is inert in relation to the surface, and the
surface, without subjection to a further treatment, is stored in an
atmosphere that is inert in relation to the anchor part surface,
and/or constantly in the presence of pure water, which can comprise
additional additives.
35. Gas-tight and liquid-tight covering containing the anchor part
according to claim 20.
36. Method according to claim 34, wherein the surface is stored in
a covering which is impermeable for gases and liquids.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of and claims priority
under 35 U.S.C. .sctn.120 to U.S. Ser. No. 11/680,055, filed Feb.
28, 2007, which claims priority to European Application No.
06004063.1, filed Feb. 28, 2006, the disclosures of which are
incorporated herein in their entirety by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a two-stage implant
comprising a base body having a bone contact surface and a tissue
contact surface and to a method for preparing such an implant.
BACKGROUND
[0003] Implants which are used for insertion into bone, for example
for attachment of artificial teeth, are known per se. Different
types of implant systems are known, for example two-part implant
systems. Said two-part implant systems comprise first an anchoring
part for anchoring within the bone and second a mounting part. Onto
the mounting part prosthesis elements, such as bridges or crowns,
are screwed or cemented usually using intermediate so-called
abutments.
[0004] A central property of said implants is their
osteointegration time, that is to say the time that passes before
the bone substance has become connected with sufficient strength
and permanently to the bone contact surface, that is to say it has
become integrated with it.
[0005] Therefore, much effort has been made in order to improve the
osteointegration of said implants, such as described in EP 1 150
620. It was shown that the osteointegration time was significantly
shorter if the bone contact surface of the implant is roughened,
hydroxylated and hydrophilic.
[0006] US 2004/0049287 discloses an endosseous implant, said
implant having a surface made from metal or ceramic. The surface
has a smooth or rough texture and has been treated with at least
one pharmaceutically acceptable organic compound carrying at least
one phosphonic acid group. Said implants showed an improved bone
bonding strength.
[0007] U.S. Pat. No. 5,397,362 discloses an implant prosthesis
comprising a substrate of a ceramic material, a glass layer coated
over the adhering interface of the substrate and a thermally
sprayed layer of calcium phosphate based material formed over the
glass layer.
[0008] WO 2005/120386 discloses a dental implant comprising an
anchoring element for anchoring the dental implant in the bone and
an abutment for fastening a crown or the like suprastructure. The
anchoring element and the abutment are produced from zirconium
oxide.
[0009] However, there is considerable evidence supporting the view
that the supracrestal connective tissue plays a fundamental role in
establishing an effective seal between the oral environment and the
endosseous part of a dental implant. Indeed, the presence of
bacteria on the implant surface may lead to an inflammation of the
peri-implant mucosa, and, if left untreated, the inflammation
spreads apically and results in bone resorption. As a consequence
of the fact that rough surfaces accumulate and retain more plaque
than smooth surfaces, nowadays, the soft tissue contact surface of
the implants is highly polished (see Oral Implantology, Thieme
Verlag, 1996, page 438).
[0010] Various experiments have been carried out to investigate the
difference of early inflammatory response to mucosa-penetrating
implants prepared with varying surface roughness. Despite the fact
that a rough surface may accumulate greater amounts of plaque than
a smooth surface, no relation was found between inflammatory
response and implant surface roughness (Wennerberg et al, J. Clin.
Periodontol 2003: 30: 88-94; Quirynen et al, The International
Journal of Oral and Maxillofacial Implants, 11, No. 2, 1996).
[0011] It is the problem of the present invention to provide an
implant with improved soft tissue integration.
SUMMARY OF THE INVENTION
[0012] An implant according to the invention comprises a base body
having a bone contact surface and a soft tissue contact surface,
wherein the soft tissue contact surface is at least partially
hydroxylated or silanated. Said soft tissue contact surface has the
potential to promote formation of soft tissue attachment. In
contrast to conventional implants having a roughened, in same cases
also hydroxylated bone contact surface and a smooth unhydroxylated
tissue contact surface, the implant according to the present
invention leads to the formation of new connective tissue adjacent
to the soft tissue contact surface of the implant and the new
connective tissue tends to be in close contact with the soft tissue
contact surface of the implant. The loose connective tissue seems
to become organized and replaced be newly formed collagen fibers,
originating from its outer zone. These fibers tend to be organized
in a perpendicular way towards the soft tissue contact surface,
similarly to the naturally occurring fibers most responsible for
compensation forces on the tooth.
[0013] An implant in terms of the present invention is intended to
mean the anchor part of a two-part implant system, that is that
part which becomes integrated with the bone. The anchoring part of
said two-part implant system may be inserted in a one-stage or a
two-stage procedure. Said anchoring part is sunk in up to about
1.5-3 mm above the bone ridge at mucosal level. Said anchor part
has a bone contact surface meaning the part which is in contact
with the bone. The top of the anchoring part which is in contact
with the soft tissue is defined as the soft tissue contact surface.
After implantation the wound edges can be directly adapted to the
soft tissue contact surface thereby effecting a primary soft tissue
closure to the implant.
[0014] "Hydroxylated" in terms of the present invention means
hydroxyl groups which are present in the outermost atomic layer of
the implant surface. If the implant comprises titanium, zirconium,
tantalum, niobium, hafnium or alloys thereof as well as chemically
similarly reacting alloys, it is assumed that the surface of metal
oxidizes spontaneously in air and water and that a reaction then
takes place with water on the surface to form hydroxyl groups. This
surface containing hydroxyl groups is referred to in the literature
as a "hydroxylated" surface; cf. H. P. Boehm, Acidic and Basic
Properties of Hydroxylated Metal Oxide Surfaces, Discussions
Faraday Society, vol. 52, 1971, pp. 264-275. The same applies to
ceramic surfaces (either on a ceramic implant or a metallic implant
with a ceramic coating). A metal surface whose hydroxyl groups are
covalently blocked, e.g. because of chemical modification, is not a
"hydroxylated" surface in terms of the present invention.
[0015] Silanated in terms of the present invention means that the
implant surface is covered by a silanole or by an organo silane
compound which has at least one free hydroxyl group. Examples of
such organo silane compounds are X.sub.nSiR.sub.4-n, wherein X is
selected from the group consisting of Cl, Br, I, F or OR, and R is
selected from the group of lower alkyl groups, such as methyl,
ethyl, propyl etc. Implants made of metal are preferably covered by
a silanole, whereas implants made of ceramic are preferably covered
by an organo silane compound. Implants made of metal can also be
covered by an organo silan compound, and implants made of ceramic
can also be covered by silanole.
[0016] In a preferred embodiment of the present invention the soft
tissue contact surface is completely hydroxylated. Such an implant
showed good results in vivo and said implants are economically
interesting and can be produced in a controlled process. In
addition it has been shown that with the implants according to the
present invention the healing process is improved, that is a good
osteointegration as well as an excellent soft tissue integration is
achieved. Therefore, the implants comprise a reduced risk of
periimplantitis and as a consequence fewer implants will have to be
replaced. Due to their purity, meaning that the soft tissue contact
surface is free of organic compounds, the surface charge is better
available. Therefore, the surface is hydrophilic, which results in
an improved soft tissue integration. Therefore, they do not bear
the risk of autoimmune reactions and other unwanted side
effects.
[0017] In a further embodiment of the present invention the soft
tissue contact surface is roughened and hydroxylated. A roughened
surface in terms of the present invention means a macroscopic
texture of the surface which is obtained for example by
sandblasting the soft tissue contact surface. It has been found
that if the soft tissue contact surface is roughened and
hydroxylated the blood coagulum is stabilized which accelerates the
healing procedure.
[0018] In a further embodiment of the present invention the soft
tissue contact surface is smooth but hydroxylated. A smooth surface
in terms of the present invention means a macroscopic texture of
the surface which is obtained for example by machining or
additional polishing, preferably by electropolishing the soft
tissue contact surface. With a smooth surface the accumulation of
plaque can be prevented or at least minimized, and such a soft
tissue contact surface has outstanding wettability properties which
is highly preferred.
[0019] In a further embodiment of the present invention the bone
contact surface and the soft tissue surface of the implant are both
roughened, hydroxylated and hydrophilic or alternatively both
smooth, hydroxylated and hydrophilic. Such implants are
particularly easy to produce since the entire implant can be
treated in the same way. This is a very big advantage and is based
on the surprising finding that a hydroxylated, hydrophilic and
roughened soft tissue surface of the implant shows improved soft
tissue integration.
[0020] In a further preferred embodiment of the present invention
the soft tissue contact surface is hydrophilic. In terms of the
present invention, the soft tissue contact surface is referred to
as "hydrophilic" if it is freely accessible to the body fluid and
not covered with foreign substances, for example substances with a
hydrophobic action. Various volatile hydrocarbons are
conventionally present in non-purified air. These are rapidly
adsorbed in a thin layer by hydroxylated and hydrophilic surfaces,
whereby such surfaces are no longer hydrophilic. Likewise, such a
hydroxylated and hydrophilic surface can become hydrophobic if the
hydroxyl groups present on the surface associate or react
chemically e.g. with carbon dioxide present in the air or with
organic solvents, such as methanol or acetone, introduced via the
cleaning process. The hydrophilic properties of the soft tissue
contact surface may result in a higher wettability when compared to
an untreated soft tissue contact surface, which promotes formation
of the soft tissue. Further, the charge on the surface is better
available which may accelerate the formation of soft tissue
attachment as well.
[0021] The implants according to the invention preferably comprise
mainly a metal selected from the group consisting of titanium,
zirconium, niobium, hafnium or tantalum, preferably titanium or
zirconium. Alternatively the implants comprise an alloy of metals
selected from the group consisting of titanium, zirconium, niobium,
hafnium or tantalum, preferably a binary titanium/zirconium alloy.
Such implants, their nature and the metal materials used to produce
them are known per se and are described for example in J. Black, G.
Hastings, Handbook of Biomaterials Properties, pages 135-200,
published by Chapman & Hall, London, 1998. From an aesthetic
point of view, in particular in the front visible region, the soft
tissue contact surface is preferably covered with a ceramic
coating. This is for example obtainable by thermally spraying a
ceramic material on the surface of a metallic core material such as
described in U.S. Pat. No. 4,746,532. Also EP 1 566 152 describes
the coating of a dental implant with zirconia. Alternatively the
implants may comprise a ceramic ring element, in particular in the
soft tissue contact surface. Such ceramic coatings and ring
elements comprise typically zirconia, aluminia, silica or mixtures
thereof with possible further constituents, preferably they are
made of zirconia. Alternatively the implant according to the
present invention may be made of ceramic.
[0022] In a most preferred embodiment the implant according to the
present invention is made of ceramic comprising a zirconium oxide
based material. The cubic structure of zirconium oxide (zirconia)
may be stabilized by metallic oxides at room temperature. Preferred
metallic oxides are magnesium oxide, calcium oxide, oxides of the
lanthanide group, preferably yttrium oxide. Depending on the
content of said metallic oxides the cubic high temperature phase of
zirconia can be stabilized fully or partly at room temperature
(cubic stabilized zirconium oxide). Preferably zirconia is
stabilized by yttrium oxide.
[0023] The present invention also relates to the process for
preparing the above disclosed implant.
[0024] To obtain the hydroxylated surface, the soft tissue contact
surface of the implant is preferably etched with an inorganic acid,
an inorganic base, a mixture of inorganic bases or a mixture of
inorganic acids. Particularly preferred are inorganic acids such as
hydrofluoric acid, hydrochloric acid, sulfuric acid, nitric acid or
a mixture of such acids. Preferably the implant is etched with a
mixture of hydrochloric acid (conc.), sulphuric acid (conc.) and
water in a weight ration of about 2:1:1. Alternatively the surface
is activated with hydrochloric acid (conc.), hydrogen peroxide
(conc.) and water in a weight ratio of about 1:1:5. The soft tissue
contact surface is then washed with pure water in an inert
atmosphere.
[0025] A roughened soft tissue contact surface can be obtained by
sandblasting said surface and keeping the surface in the resulting
state if it is already hydroxylated and hydrophilic or converting
the sandblasted surface to a hydroxylated and hydrophilic state in
a separate process step.
[0026] In particular, the roughened soft tissue contact surface can
be produced by shot peening or sandblasting said surface and/or
roughening it by using plasma technology, and then treating the
mechanically roughened surface by an electrolytic or chemical
process until a hydroxylated and hydrophilic surface is formed.
[0027] The preferred procedure is to [0028] shot-peen the soft
tissue contact surface of the implant and then etch it with diluted
hydrofluoric acid at room temperature; or [0029] sandblast the soft
tissue contact surface of the implant, e.g. with aluminium oxide
particles having a mean size of 0.1-0.25 mm or 0.25-0.5 mm, and
then treat it at elevated temperature with a hydrochloric
acid/sulfuric acid mixture and wash it with pure distilled and
carbon-free (CO.sub.2 and other carbons) water; or [0030] sandblast
the soft tissue contact surface of the implant with coarse
particles, e.g. with a mixture of particles as defined above, and
then treat it with a hydrochloric acid/nitric acid mixture and wash
it with pure distilled and carbon-free (CO.sub.2 and other carbons)
water; or [0031] treat the soft tissue contact surface of the
implant with a mixture of hydrochloric acid (conc.), hydrogen
peroxide (conc.) and water in a weight ratio of about 1:1:5 and
wash it with pure distilled and carbon-free (CO.sub.2 and other
carbons) water; or [0032] roughen the soft tissue contact surface
by using plasma technology and then hydroxylate it in a mixture of
hydrochloric acid (conc.), hydrogen peroxide (conc.) and water in a
weight ratio of about 1:1:5 and wash it with pure distilled and
carbon-free (CO.sub.2 and other carbons) water; or [0033] treat the
soft tissue contact surface by an electrolytic process, optionally
after mechanical roughening of the surface, and then wash it with
pure distilled and carbon-free (CO.sub.2 and other carbons) water;
or [0034] treat the soft tissue contact surface of the implant by
plasma cleaning or UV-treatment.
[0035] These methods are known to those skilled in the art and are
described for example in U.S. Pat. No. 5,071,351, The hydroxylated
soft tissue contact surface of the implant is after such a
treatment free of organic debris and has increased wettability. As
a result, the implant becomes more intimately involved with the
surrounding bone and tissue structure.
[0036] Whatever the case may be, according to the invention the
implant is not subjected to further aftertreatment, i.e. it is not
treated with alcohol, acetone or any other organic solvent. In
particular, said pure water contains neither carbon dioxide nor
hydrocarbon vapours and especially no acetone and no alcohols like
methanol or ethanol. However, it can contain special additives as
described below. The "pure" water used for washing has preferably
been distilled several times or prepared by reverse osmosis; the
water has preferably been prepared in an inert atmosphere, i.e.
under reduced pressure in a nitrogen or noble gas atmosphere, for
example.
[0037] Following these procedures, the implant 1 obtained is left
in pure water and stored in a closed vessel or a covering 2, as
shown in FIG. 2. In addition to water, the interior of the covering
can contain inert gases 3, for example nitrogen, oxygen or a noble
gas such as argon. The implant obtained is preferably stored in
pure water optionally containing selective additives, and in a
covering which is practically impermeable to gases and liquids,
especially to carbon oxides, the interior of the covering being
devoid of any compounds capable of impairing the activity of the
implant surface.
[0038] Alternatively, the implant could be placed in an inert gas
atmosphere.
[0039] The implant according to the invention, or at least its
hydroxylated and hydrophilic surface, is preferably sealed in a
gas-tight and liquid-tight covering, the interior of the covering
being devoid of any compounds capable of impairing the biological
activity of the implant surface. In this way it is avoided that the
surface loses its activation fully or partially by means of air
constituents, before the dental implant is applied. In a preferred
embodiment there is a reducing atmosphere in the interior of the
covering. This gas-tight and liquid-tight covering is preferably a
heat-sealed ampoule made of glass, metal, a synthetic polymer or
some other gas-tight and liquid-tight material, or a combination of
these materials. The metal preferably takes the form of a thin
sheet, it being possible for polymeric materials and metal sheets,
as well as glass, to be combined together to form a suitable
packaging in a manner known per se.
[0040] Examples of suitable additives which can be incorporated in
the pure water are cations and anions which already occur in the
body fluid. In order to stabilize the positive charge the implant
according to the present invention is preferably stored at a pH
ranging from pH 3 to 7, preferably 4 to 6. Alternatively it is also
possible to store the implant at a pH ranging from pH 7 to 10 in
order to stabilize the negative charge. Preferred cations are
Na.sup.+, K.sup.+, Mg.sup.2+ and Ca.sup.2+. The preferred anion is
Cl.sup.-. The total amount of said cations or anions ranges
preferably from about 50 mM to 250 mM, particularly preferably from
about 100 mM to 200 mM, and is preferably about 150 mM. If the
covering contains divalent cations, especially Mg.sup.2+,
Ca.sup.2+, Sr.sup.2+ and/or Mn.sup.2+, on their own or in
combination with the above-mentioned monovalent cations, the total
amount of divalent cations present preferably ranges from 1 mM to
20 mM.
[0041] The invention is explained below on the basis of figures and
illustrative embodiments, without in any way limiting the invention
to the embodiments shown.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 shows the different areas of an embodiment of an
implant according to the invention that is the anchoring part of a
two-part implant system.
[0043] FIG. 2 shows an implant system according to the
invention.
DETAILED DESCRIPTION
[0044] In accordance with one embodiment of the invention, FIG. 1
shows an implant 1 which is preferably made of a tissue compatible
metal or of an alloy of such a metal, in particular of titanium or
of a titanium alloy. Alternatively the implant is made of ceramic,
preferably of zirconia. Further it is possible that parts of the
implant are made of metal and parts of the implant are made of
ceramic, for example if the inner part is made of titanium and the
outer part of the implant is made of ceramic. The implant 1 has a
threaded section 10 and a rounded lower end 15. At its upper end it
has a slightly enlarged conical section 20. Said implant 1 is
subdivided into a bone contact surface B and a soft tissue contact
surface S. In the boundary area of these surfaces, there is a
transition area B/S from bone contact surface B to soft tissue
contact surface S, which transition area is assigned to both
aforementioned areas. The question of whether this area, in the
implanted state, is located in the bone or in the soft tissue
depends on a large number of factors, for example the depth to
which the implant is screwed, the tissue reaction, etc. The
transition area has to be treated in the same way as the bone
contact surface, in order to make sure, that in any case an optimal
osteointegration is ensured. In the case of implants 1 made of
titanium, the bone contact surface is preferably roughened, and
even more preferred hydroxylated and hydrophilic as well. The soft
tissue contact surface S is at least partially, preferably
completely hydroxylated. In a preferred embodiment it is also
roughened and/or hydrophilic. The soft tissue contact surface of an
implant according to the present invention may be made of titanium,
zirconium, tantalum, niobium, hafnium or alloys thereof as well as
chemically similarly reacting alloys, but it is also possible that
the implant has a ceramic coating which is hydroxylated.
[0045] The Examples which follow illustrate the invention.
Example 1
Implant with a Roughened Hydroxylated Soft Tissue Contact
Surface
[0046] A common shape of dental implant in the form of a screw of
diameter 4 mm and length 10 mm was produced. The crude shape was
obtained in a manner known per se by removing material from the
cylindrical blank by turning on a lathe and milling. The bone
contact surface as well as the soft tissue surface were then
sandblasted with particles having a mean size of 0.25-0.5 mm as
described in EP 0 388 575. The roughened surface was then treated
for about five minutes at a temperature above 80.degree. C. with an
aqueous hydrochloric acid (conc.)/sulfuric acid (conc.) mixture
having an HCl:H.sub.2SO.sub.4:H.sub.2O ratio of 2:1:1. The implant
formed in this way was washed with pure water and then heat-sealed
directly in a glass ampoule filled with pure water containing 150
mM Na.sup.+ ions, and the corresponding amount of Cl.sup.-
anions.
[0047] To test the soft tissue integration, the above implants were
placed in four female fox hounds. Each animal received 6 implants
bilaterally in the upper jaw and 10 implants bilaterally in the
lower jaw. The implants with a roughened hydroxylated soft tissue
contact surface showed unexpectedly a much better soft tissue
integration than comparable implants with an unhydroxylated
surface. Soft tissue adhesion was seen already after a few days,
the soft tissue integration was apparent within two weeks.
Example 2
Implant with a Smooth Hydroxylated Soft Tissue Contact Surface
[0048] A common shape of dental implant in the form of a screw of
diameter 4 mm and length 10 mm was produced. The crude shape was
obtained in a manner known per se by removing material from the
cylindrical blank by turning on a lathe and milling. The bone
contact surface was then sandblasted with particles having a mean
size of 0.25-0.5 mm, whereas the soft tissue contact surface has
been electropolished. The sandblasted bone contact surface as well
as the electropolished soft tissue contact surface were then
treated for about five minutes at a temperature above 80.degree. C.
with an aqueous hydrochloric acid (conc.)/sulfuric acid (conc.)
mixture having an HCl:H.sub.2SO.sub.4:H.sub.2O ratio of 2:1:1. The
implant formed in this way was washed with pure water and then
heat-sealed directly in a glass ampoule filled with pure water
containing 150 mM Na.sup.+ ions, and the corresponding amount of
Cl.sup.- anions.
[0049] To test the soft tissue integration, the above implants were
placed in four female fox hounds. Each animal received 6 implants
bilaterally in the upper jaw and 10 implants bilaterally in the
lower jaw. The implants with a smooth hydroxylated soft tissue
contact surface showed unexpectedly a much better soft tissue
integration than comparable implants with an unhydroxylated
surface. Soft tissue adhesion was seen already after a few days,
the soft tissue integration was apparent within two weeks.
* * * * *