U.S. patent application number 10/976734 was filed with the patent office on 2005-03-17 for method for producing tooth replacements and auxiliary dental parts.
Invention is credited to Dolabdjian, Haig, Strietzel, Roland.
Application Number | 20050056350 10/976734 |
Document ID | / |
Family ID | 34279311 |
Filed Date | 2005-03-17 |
United States Patent
Application |
20050056350 |
Kind Code |
A1 |
Dolabdjian, Haig ; et
al. |
March 17, 2005 |
Method for producing tooth replacements and auxiliary dental
parts
Abstract
In a method for forming a dental part, a laser beam is guided
over a powder layer of biocompatible material. The laser is guided
by a computer controlled laser scanning system based on data
representing the shape of the cross-section through the shaped
body. The powder is substantially melted by the laser beam to form
a layer in the shaped body, to build the shaped body entirely from
layers of laser-melted material.
Inventors: |
Dolabdjian, Haig;
(Feldkirchen, DE) ; Strietzel, Roland;
(Lilienthal, DE) |
Correspondence
Address: |
ALTERA LAW GROUP, LLC
6500 CITY WEST PARKWAY
SUITE 100
MINNEAPOLIS
MN
55344-7704
US
|
Family ID: |
34279311 |
Appl. No.: |
10/976734 |
Filed: |
October 29, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10976734 |
Oct 29, 2004 |
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10146610 |
May 14, 2002 |
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10146610 |
May 14, 2002 |
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10081039 |
Feb 19, 2002 |
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Current U.S.
Class: |
148/512 |
Current CPC
Class: |
A61C 5/77 20170201; A61C
13/0004 20130101; A61K 6/84 20200101; B33Y 10/00 20141201; A61C
13/20 20130101; Y02P 10/25 20151101; A61C 13/09 20130101; A61C
13/0018 20130101; B28B 1/001 20130101; B33Y 80/00 20141201; B22F
10/20 20210101; A61C 5/73 20170201; A61C 13/0003 20130101 |
Class at
Publication: |
148/512 |
International
Class: |
B22F 003/105 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 19, 1999 |
DE |
199 01 643.7 |
Claims
What is claimed is:
1. A method of making a shaped body for use as a dental part,
comprising: guiding a laser beam over a powder layer using a
computer-controlled laser scanning system based on data
representing the shape of a cross-section through the shaped body,
the powder comprising a biocompatible material of grain size in the
range from 0 .mu.m to 50 .mu.m, to create a layer in the shaped
body; substantially melting the powder with the laser beam; and
repeating the guiding and melting over successive powder layers
using successive cross-sectional representative data so as to build
the shaped body entirely from layers of laser-melted material.
2. The method as recited in claim 1, wherein the molten powder
substantially maintains the shape of each cross-section through the
shaped body.
3 The method as recited in claim 1, wherein the shaped body has an
average density of up to 98% of the density of the biocompatible
material.
4. The method as recited in claim 1, wherein the shaped body has an
average density of up to 99.9% of the density of the biocompatible
material.
5. The method as recited in claim 1, wherein the powder comprises
an alloy with essentially equal proportions of alloy components in
each grain of the powder.
6. The method as recited in claim 1, wherein the biocompatible
material is a metal alloy.
7. The method as recited in claim 1, wherein the biocompatible
material is Ni61.4, Cr22.9, Mo8.8, Nb3.9, Fe2.5, Mn0.4, and
Ti0.1.
8. An intermediate for being made into a shaped dental part for use
in a patient's mouth, comprising: a partial body comprising
biocompatible material and having a surface shaped to fit in the
patient's mouth; and a layer of powder alloy disposed upon a
surface of the partial body and comprising particles of the
biocompatible material, the particles generally being of a
predetermined density, having varying grain sizes in a range of
about 0 .mu.m to about 50 .mu.m, and having essentially equal
proportions of alloy components in each particle; wherein the
biocompatible material of the partial body has a density of not
less than about 98% of the predetermined density of the
particles.
9 The intermediate as recited in claim 8, wherein the biocompatible
material of the partial body has a density between 98% and 99.9% of
the predetermined density.
10 The intermediate as recited in claim 8, wherein the
biocompatible material is a metal alloy.
11. The intermediate as recited in claim 8, wherein the
biocompatible material is 61.4% Ni, 22.9% Cr, 8.8% Mo, 3.9% Nb,
2.5% Fe, 0.4% Mn, and 0.1% Ti.
12. The intermediate as recited in claim 8 wherein the particle
layer is of a thickness for forming a layer of cohesively
maintained biocompatible material, when melted by a guided laser
beam, to enlarge the partial body.
13. An intermediate for being made into a shaped dental part for
use in a patient's mouth, comprising: a partial body comprising
biocompatible material and having a surface shaped to fit in the
patient's mouth; and a layer of powder alloy disposed upon a
surface of the partial body and consisting of particles of
biocompatible material generally having a predetermined density and
essentially equal proportions of alloy components, the particles
further having varying grain sizes in a range of from about 0 .mu.m
to about 50 .mu.m; wherein the biocompatible material of the
partial body has a density of not less than about 98% of the
predetermined density of the particles; and wherein the particle
layer is of a thickness for forming a layer of cohesively
maintained biocompatible material, when melted by a guided laser
beam, to enlarge the partial body.
14. The intermediate as recited in claim 14, wherein the
biocompatible material is a metal alloy.
15. The intermediate as recited in claim 14, wherein the
biocompatible material is 61.4% Ni, 22.9% Cr, 8.8% Mo, 3.9% Nb,
2.5% Fe, 0.4% Mn, and 0.1% Ti.
Description
[0001] The present application is a divisional of prior application
Ser. No. 10/146,610 filed 14 May 2002, which is a
continuation-in-part of application Ser. No. 10/081,039 filed 19
Feb. 2002.
FIELD OF THE INVENTION
[0002] This invention relates to a method of forming a dental part
and/or a tooth replacement part.
BACKGROUND OF THE INVENTION
[0003] Tooth replacements in the form of crowns, bridges, inlays
and the like frequently comprise complex molded bodies which must
usually take account in each specific case of the spatial
configuration of intact tooth parts (tooth stumps), entire teeth or
parts of the jaw that have been lost, on the one hand, and the
spatial situation in relation to adjacent and/or antagonistic
teeth, on the other hand. In the prior art, such tooth replacement
elements are produced in complex processes. The most widespread
method is to produce the shaped bodies required--usually made of
precious-metal or base-metal alloys, as well as pure metals--in a
multi-step impression and casting process.
[0004] Computer-controlled milling of such shaped bodies out of the
solid material has become known. This method inevitably leads to
considerable waste that has to be reprocessed at great effort and
expense.
SUMMARY OF THE INVENTION
[0005] The objective of the invention is to provide another, more
advantageous way of producing such shaped bodies (and auxiliary
dental parts required in implantology) that provides flexibility in
manufacturing dental parts of different shapes, but which reduces
the amount of waste and results in a strong dental part.
[0006] A method in accordance with the principles of the invention
includes a method of making a shaped body for use as a dental part.
The method comprises guiding a laser beam over a powder layer using
a computer-controlled laser scanning system based on data
representing the shape of a cross-section through the shaped body.
The powder comprises a biocompatible material of grain size in the
range from 0 .mu.m to 50 .mu.m, to create a layer in the shaped
body. The method further comprises substantially melting the powder
with the laser beam, and repeating the guiding and melting over
successive powder layers using successive cross-sectional
representative data so as to build the shaped body entirely from
layers of laser-melted material.
[0007] In another embodiment of the present invention, a shaped
dental part for use in a patient's mouth. The shaped dental part
comprises a body formed from melted particles of biocompatible
material, the body having a surface shaped to fit in the patient's
mouth and having a density of up to 98% of the density of the
biocompatible material. The particles having pre-melting sizes in
the range 0 .mu.m-50 .mu.m, and having essentially equal
proportions of alloy components in each particle.
DETAILED DESCRIPTION OF THE INVENTION
[0008] The invention relates to a method that has become known in
another field as "rapid prototyping" for producing complex tools or
components as disclosed in U.S. Pat. No. 4,863,538 included herein
by reference. According to said method, shaped bodies made of a
sintering powder are built up in layers by exposing each layer
successively to the energy of a laser beam that leads to local
sintering, whereby the laser beam is guided over the respective
powder layer by means of a computer-controlled system using data
that represent the configuration of the shaped piece in this layer.
As a result of supplying such energy, the powder elements affected
in each case are superficially melted and form a fixed bond with
each other and the underneath layer. Due to the precise focusing of
the laser beam, the energy supply can be configured exactly--at
relatively high density--and controlled in accordance with the
stored spatial data of the shaped body required.
[0009] Conventionally, in a sintering process, compressed powdered
material is heated to a temperature close to but not at melting,
usually in a controlled-atmosphere furnace. This is done so that
particles may bond by solid state bonding, but not melt. Such
sintering increases both density and strength of the material,
because compaction alone leads to both properties being low. The
latter is also true with sintering without compaction (compressing)
the powdered material, as is the case with the selective sintering
process addressed before.
[0010] It has been found that, rather than selectively sintering
metal powder by superficially melting the uncompressed material, a
still considerably higher density of the finished product can be
achieved by substantially entirely melting the powdered material,
primarily metal. Quite surprisingly, such "selective melting" of
the powder does not lead to uncontrolled flowing away of the
material, probably because the cohesion forces suffice to keep the
thin layer of material in place, even in its molten state.
[0011] Using this method of "selective melting", the porosity of
the resultant part is significantly less than what is achieved
under conventional laser sintering. For example, densities achieved
with the conventional selective laser sintering technique ranges
from 70-80%, while the densities achieved through ceramic sintering
techniques range from 60-70%. In contrast, the density of the
resultant part using a method according to the invention may be
greater than 98% of the density of the biocompatible material, and
may be as high as 99.9% of the density of the biocompatible
material. Thus, a dense, and therefore strong, part may be formed
using the laser selective melting technique. This permits the
resultant part to be made with the desired shape without using a
mold, but the part is also more able to withstand the high stresses
that result from biting and chewing.
[0012] Furthermore, the invention provides for a powder consisting
of a biocompatible material of varying grain size between 0 and 50
.mu.m. In contrast to current application of the selective laser
sintering method for technical purposes, the invention thus ensures
that the shaped body designed for dental purposes is compatible
with human tissue (see Hoffmann-Axthelm, Lexikon der Zahnmedizin
[Encyclopedia of Dental Medicine], 6th/11th edition, p. 97, and
Reuling, Biokompatibilitt dentaler Legierungen [Biocompatibility of
Dental Alloys]). The grain size distribution ensures the forming of
dense layers with the advantage of minimal creation of cavities
between the layer after melting, which would be susceptible to
bacteria cultures forming; in addition, it defines the size and
fitting accuracy of the restoration.
[0013] While larger cross-sectional areas of the dental part to be
produced, are impacted by the laser beam by oscillating it in one
direction, and shifting the oscillating beam in a direction
perpendicular thereto, as explained in U.S. Pat. No. 4,863,538
mentioned above, according to the invention the laser beam follows
the contour of the wall to be produced within the cross-section of
thin-walled areas.
[0014] Due to its certain degree of roughness, the surface of the
shaped body produced in accordance with the invention is
particularly well-suited for the frequently desired veneering
process using ceramic or other materials, as is the case with
crowns or bridges. Furthermore, because it is easy to influence the
file on which the control process is based, it is possible to make
corrections to the configuration of the shaped body that may appear
desirable (with respect to the traced result) for a wide variety of
reasons.
[0015] The powder preferably comprises an alloy with essentially
equal proportions of the alloy components in each grain of powder.
This provides a major advantage compared to the conventional
production of shaped dental bodies from melted alloys, because
there is no risk of segregation of the alloy components in the melt
and/or in the shaped body after casting. In addition, the
production of semi-finished products that are made of certain
alloys and are particularly advantageous for dental purposes
necessitates complicated and costly processes, such as suction
casting and the like, whereas pulverization of such alloys is
significantly less complex. However, whereas a melt produced from
such a powder (for subsequent production of shaped cast bodies) is
exposed for its part to the risk of segregation and thus
non-homogeneity, a shaped body that is selectively melted according
to the invention maintains its uniform distribution of alloy
components.
[0016] A metal powder with the following composition has proved
effective for use with the method according to the invention,
whereby the method is not confined to said composition: Ni61,
4Cr22, 9M08, 8Nb3, 9Fe2, 5Mn0.4Ti0.1, where the alloy comprises
61.4% Ni, 22.9% Cr, 8.8% Mo, 3.9% Nb, 2.5% Fe, 0.4% Mn and 0.1%
Ti.
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