(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(19) World Intellectual Property
`Organization
`International Bureau
`
`(43) International Publication Date
`12 February 2004 (12.02.2004)
`
` (10) International Publication Number
`
`WO 2004/012620 A2
`
`(51) International Patent Classification7:
`
`A61C
`
`(21) International Application Number:
`PCT/US2003/024461
`
`(22) International Filing Date:
`
`5 August 2003 (05.08.2003)
`
`(25) Filing Language:
`
`(26) Publication Language:
`
`English
`
`English
`
`(30) Priority Data:
`60/401,303
`
`5 August 2002 (05.08.2002,)
`
`US
`
`(71) Applicant (for all designated States except US): LIQUID-
`METAL TECHNOLOGIES [US/US]; Suite 3150, 100
`North Tampa Street, Tampa, FL 33602 (US).
`
`(72) Inventors; and
`(75) Inventors/Applicants (for US only): PEKER, Atakan
`[TR/US]; 17 Coffeeberry, Aliso Viejo, CA 92656 (US).
`KIM, Choongnyun, Paul [US/US]; 19563 Turtle Ridge
`Lane, Northridge, CA 91326 (US). NGUYEN, Tranquoc,
`Thebao [US/US]; 2568 W. Rome Avenue, Anaheim, CA
`92804 (US).
`
`(74) Agent: PECK, John, W.; Christie, Parker & Hale, LLP,
`Post Office Box 7068, Pasadena, CA 9110977068 (US).
`
`(81) Designated States (national): AE, AG, AL, AM, AT, AU,
`AZ, BA, BB, BG, BR, BY, BZ, CA, CH, CN, CO, CR, CU,
`CZ, DE, DK, DM, DZ, EC, EE, ES, FI, GB, GD, GE, GH,
`GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC,
`LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW,
`MX, MZ, NO, NZ, OM, PH, PL, PT, RO, RU, SC, SD, SE,
`SG, SK, SL, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ,
`VC, VN, YU, ZA, ZM, ZW.
`
`(84) Designated States (regional): ARIPO patent (GH, GM,
`KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZM, ZW),
`Eurasian patent (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM),
`European patent (AT, BE, BG, CH, CY, CZ, DE, DK, EE,
`ES, FI, FR, GB, GR, HU, IE, IT, LU, MC, NL, PT, RO,
`SE, SI, SK, TR), OAPI patent (BF, BJ, CF, CG, CI, CM,
`GA, GN, GQ, GW, ML, MR, NE, SN, TD, TG).
`
`Published:
`without international search report and to be republished
`upon receipt of that report
`
`For two-letter codes and other abbreviations, refer to the "Guid-
`ance Notes on Codes and Abbreviations ” appearing at the beg in-
`ning of each regular issue of the PCT Gazette,
`
`(54) Title: NIETALLIC DENTAL PROSTHESES MADE OF BULK—SOLIDIFYHVG AMORPHOUS ALLOYS AND METHOD
`OF MAKING SUCH ARTICLES
`
`Step 1
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`Step 2
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`T>Tmelt
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`
`
`
`
`
`
`
`
`
`
`Step 5
`
`T~Tambient
`
`T
`Step 4
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`(57) Abstract: Metallic dental prostheses made of bulk—solidifying amorphous alloys wherein the dental prosthesis has an elastic
`strain limit of around 12% or more and methods of making such metallic dental prostheses are provided.
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`METALLIC DENTAL PROSTHESES MADE OF BULK-SOLIDIFYlNG AMORPHOUS
`
`ALLOYS AND METHOD OF MAKING SUCH ARTICLES
`
`FIELD OF THE INVENTION
`
`The present
`
`invention relates to metallic dental prostheses constructed of bulk—
`
`solidifying amorphous alloys and methods of making such articles.
`
`BACKGROUND OF THE INVENTION
`
`Metallic dental prostheses, such as crown and bridges, are each custom-made to
`
`replicate the impressions made for a specific tooth/teeth. Generally, metallic dental
`
`materials are chosen for their ability to replicate the exact features of the impression during
`
`casting, and the ability to attain a high quality surface finish during the post-cast finishing
`
`process. In addition, the choice of dental material should have a high yield strength and
`
`sufficient hardness to endure the stresses created by chewing, and sufficient erosion/corrosion
`
`resistance to withstand the harsh chemical environment created by various foods, by the
`
`body, and by the environment. Finally, the material of choice should have a relatively low
`
`coefficient of thermal expansion to be compatible with the tooth and other porcelain materials
`
`it is place in contact with.
`
`The principal materials of choice for metallic dental prostheses are noble-metal based
`
`alloys, such as gold alloys, which are corrosion resistant and have better relative castability
`
`than conventional high strength materials. However,
`
`these noble-metal based alloys are
`
`expensive materials and generally do no have high yield strength and hardness. Other
`
`materials of choice, such as nickel-base alloys, are difficult to cast and do not sufficiently
`
`replicate the exact features of the intricate impressions.
`
`Accordingly, there is a need for a new material for metallic dental prOstheses, with
`
`high castability and replication characteristics, high yield strength and hardness, high
`
`corrosion resistance, and that are preferably relatively inexpensive.
`
`SUMMARY OF THE INVENTION
`
`The current
`
`invention is directed to metallic dental prostheses made of bulk-
`
`solidifying amorphous alloys wherein the dental prosthesis has an elastic strain limit of
`
`around 1.8% or more, and methods of making such metallic dental prostheses.
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`In one embodiment of the invention, the metallic dental prosthesis is made of a bulk-
`
`solidifying amorphous alloy.
`
`In one preferred embodiment of the invention, the metallic
`
`dental prosthesis is made of a Zr/Ti base bulk—solidifying amorphous alloy incorporating in—
`
`situ ductile crystalline precipitates.
`
`In another preferred embodiment of the invention, the metallic dental prosthesis is
`
`made of a Zr/Ti base bulk-solidifying amorphous alloy incorporating no Nickel.
`
`In still another preferred embodiment of the invention, the metallic dental prosthesis
`
`is made of a Zr/Ti base bulk-solidifying amorphous alloy incorporating no Aluminum.
`
`In yet another preferred embodiment of the invention, the metallic dental prosthesis is
`
`made of a Zr/Ti base bulk-solidifying amorphous alloy incorporating no Beryllium.
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`at least in part of another dental material.
`
`In still another embodiment of the invention, the metallic dental prosthesis is coated
`
`with a biocompatible polymethyl methacrylate resin cement. In such an embodiment the
`
`cement can be reinforced with selected oxides including alumina, magnesia, zirconia, or a
`
`combination of these oxides along with an application of a small amount of a metal primer
`
`agent.
`
`In yet another embodiment of the invention, the metallic dental prosthesis is a casting
`
`of a bulk-solidifying amorphous alloy. In a preferred embodiment of the invention, metallic
`
`dental prosthesis is an investment casting of a bulk-solidifying amorphous alloy.
`In still yet another embodiment of the invention, the metallic dental prosthesis is a
`
`crown. In another embodiment of the invention, the metallic dental prosthesis is a bridge.
`
`In still yet another embodiment the invention is directed to a method of forming a
`
`dental prosthesis of a bulk-solidifying alloy.
`
`In one such embodiment, a molten piece of
`
`bulk-solidifying amorphous alloy is cast into a near-to-net shape dental prostheses. In a
`
`preferred embodiment of the invention a molten piece of bulk-solidifying amorphous alloy is
`
`investment—cast into a near—to—net shape dental prostheses.
`
`In another preferred embodiment
`
`of the invention, a molten piece of bulk—solidifying amorphous alloy is cast into a near-to-net
`
`shape crown. In. still anther pre-_. - .
`
`_ _-
`
`--
`
`-
`
`.
`
`A. - -
`
`-,
`
`-
`
`solidifying amorphous alloy is investment—cast into a near-to-net shape crown. In yet another
`
`preferred embodiment of the invention, a molten piece of bulk—solidifying amorphous alloy is
`
`cast
`
`into a near—to-net shape bridge. In still yet another preferred embodiment of the
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`invention, a molten piece of bulk-solidifying amorphous alloy is investment-cast into a near-
`
`to—net shape bridge.
`
`In another embodiment of the method of making dental prostheses,
`
`the bulk
`
`solidifying amorphous alloy composition has a critical cooling rate of 100 °C/second or less
`
`and preferably 10 °C/second or less.
`
`In still another embodiment of the method of making dental prostheses, the provided
`
`bulk solidifying amorphous alloy composition is selected fiom the group consisting of: Zr/Ti
`
`base, Zr-base, Zr/Ti base with no Ni, Zr/Ti base With no Al, and Zr/Ti base with no Be.
`
`In yet another embodiment of the method of making dental prostheses, a molten piece
`
`of the bulk-solidifying amorphous alloy is cast into a dental prosthesis under either a partial
`nrninm
`111111111m
`Von/um“. 01' a. V avuvuu.
`
`In still yet another embodiment of the method of making dental prostheses, a molten
`
`piece of the bulk—solidifying amorphous alloy is fed into the mold by applying an external
`
`pressure such as an inert gas.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`These and other features and advantages of the present invention will be better understood by
`
`reference to the following detailed description when considered in conjunction with the
`
`accompanying drawing wherein:
`
`Figure 1 shows a flow—chart an exemplary embodiment of a method of producing a metallic
`
`dental prosthesis according to the current invention.
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`The current
`
`invention is directed to metallic dental prostheses made of bulk—
`
`solidifying amorphous alloys wherein the dental prosthesis has an elastic strain limit of
`
`around 1.8% or more,. and methods of making such metallic dental prostheses.
`
`Metallic dental prostheses, such as crowns and bridges, are each custom-made to
`
`replicate the impressions made for a specific tooth/teeth. In dental terminology, the crown is
`
`the visi- 1e part of tooth, which ca- be fi.nth_.r c_v_.r_.d by enamel to imp
`
`.
`
`»
`
`.
`
`n .
`
`and durability of the prosthesis. Such a crown can be an artificial replacement for the visible
`
`part of a tooth that has decayed or been damaged. In such an embodiment, the crown is a
`
`restoration that covers, or caps, a tooth to restore it to its normal shape and size. However, the
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`crown can also serve to strengthen or improve the appearance of a tooth. Finally, the crown
`
`can also be used to cover a dental implant.
`
`In contrast, a bridge is a partial false tooth, or a set of one or more false teeth that act
`
`as a replacement for missing natural teeth. Such a bridge can be permanently anchored to
`
`natural teeth (fixed bridge) or set into a metal appliance and temporarily clipped onto natural
`
`teeth (removable bridge).
`
`Bulk solidifying amorphous alloys are recently discovered family of amorphous
`
`alloys, which can be cooled at substantially lower cooling rates, of about 500 K/sec or less,
`
`and substantially retain their amorphous atomic structure. As such, these materials can be
`
`produced in thickness of 1.0 mm or more, substantially thicker than conventional amorphous
`
`K/sec or more. Exemplary bulk—solidifying amorphous alloy materials are described in US
`
`Patent Nos. 5,288,344; 5,368,659; 5,618,359; and 5,735,975 (the disclosures of which are
`
`incorporated in their entirety herein by reference).
`
`One exemplary family of bulk solidifying amorphous alloys can be described as
`
`(Zr,Ti)a(Ni,Cu, Fe)b(Be,Al,Si,B)c, where a is in the range of from 30 to 75, b is in the range of
`
`from 5 to 60, and c in the range of from 0 to 50 in atomic percentages. Furthermore, these
`
`alloys can accommodate other transition metals, such as Nb, Cr, V, Co, in amounts up to 20
`
`% atomic and more.
`
`A preferable alloy family is (Zr,Ti)a(Ni,Cu)b(Be)c, where a is in the range of from 40
`
`to 75, b is in the range of fiom 5 to 50, and c in the range of from 5 to 50 in atomic
`
`percentages. Still, a more preferable composition is (Zr,Ti)a(Ni,Cu)b(Be)c, where a is in the
`
`range of from 45 to 65, b is in the range of from 7.5 to 35, and c in the range of from 10 to
`
`37.5 in atomic percentages. Another preferable alloy family is (Zr)a (Nb,Ti)b Wi,Cu)c(Al)d,
`
`where a is in the range of from 45 to 65, b is in the range of from O to 10, c is in the range of
`
`from 20 to 40 and d in the range of from 7.5 to 15 in atomic percentages. Other elements, e. g
`
`Y, Si, Sn, Sc etc. can also be added as micro-alloying additions to the composition of bulk
`
`solidifying amorphous alloys at fractions of atomic percentages in order to alleviate the
`
`effects of detrimental impurities such as ox gen 3
`
`These bulk—solidifying amorphous alloys can sustain strains up to 1.5 % or more and
`generally around 1.8 % without any permanent deformation or breakage. Further, they have
`
`high fracture toughness of 10 ksi-sqrt(in) (sqrt : square root) or more, and preferably 20 ksi
`
`sqrt(in) or more. Also, these materials have high hardness values of 4 GPa or more, and
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`preferably 5.5 GPa or more. The yield strength of bulk solidifying alloys range from 1.6 GPa
`
`and reach up to 2 GPa and more exceeding the current state of the Titanium alloys.
`
`Another set of bulk-solidifying amorphous alloys are ferrous metals (Fe, Ni, Co)
`
`based compositions. Examples of such compositions are disclosed in US. Patent No.
`
`6,325,868; publications to (A. Inoue et. al., Appl. Phys. Lett., Volume 71, p 464 (1997)) and
`
`(Shen et. al., Mater. Trans, JHVI, Volume 42, p 2136 (2001)); and Japanese patent application
`
`2000126277 (Publ. # .2001303218 A), all of which are incorporated herein by reference.
`
`One exemplary composition of such alloys is Fe7zAlsGa2P11C6B4. Another exemplary
`
`composition of such alloys is Fe72Al7Zr10M05W2B15. Although, these alloy compositions are
`
`not processable to the degree of the above-cited Zr—base alloy systems, they can still be
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`
`invention. Similarly, these materials have elastic strain limits higher than 1.2% and generally
`
`around 1.8 %. The yield strength of these ferrous-based bulk-solidifying amorphous alloys is
`
`also higher than the Zr-based alloys, ranging from 2.5 GPa to 4 GPa, or more, making them’
`
`particularly attractive for use in dental prostheses. Ferrous metal—base bulk amorphous alloys
`
`also very high yield hardness ranging from 7.5 GPA to 12 GPa.
`
`In general, crystalline precipitates in bulk amorphous alloys are highly detrimental to
`
`the properties of bulk—solidifying amorphous alloys, especially to the toughness and strength
`
`of these materials, and, as such, such precipitates are generally kept to as small a volume.
`
`fraction as possible. However, there are cases in which ductile crystalline phases precipitate
`
`in—situ during the processing of bulk amorphous alloys and are indeed beneficial to the
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`properties of bulk amorphous alloys, and especially to the toughness and ductility of the
`
`materials. Such bulk amorphous alloys comprising such beneficial precipitates are also
`
`included in the current invention. One exemplary material is disclosed in (CC. Hays et. a1,
`
`Physical Review Letters, Vol. 84, p 2901, 2000), which is incorporated herein by reference.
`
`This alloy has a low elastic modulus of from 70 GPa to 80 GPa depending on the specific
`
`microstructure of ductile-crystalline precipitates. Further, the elastic strain limit is 1.8% or
`
`more and the yield strength is 1.4 GPa and more.
`
`prostheses, Applicants have found that dental prostheses constructed of bulk-solidifying
`
`amorphous alloys show a number of improved properties. First, as described above, bulk
`
`solidifying amorphous alloys have the high hardness and toughness properties associated
`
`with conventional materials. The bulk solidifying amorphous alloys also have excellent
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`corrosion resistance, as required for any material exposed to the harsh conditions to which
`
`dental prostheses are subjected. However, these bulk—solidifying amorphous alloys also have
`
`some general characteristics which make bulk-solidifying amorphous alloys uniquely suited
`
`as a new class of material for the use and application in metallic dental prostheses.
`
`Bulk—solidifying amorphous alloys have very high elastic strain limits, or the ability td
`
`sustain strains without permanent deformation, typically around 1.8 % or higher. Although
`
`Applicant’s have discovered that this is an important characteristic for dental prostheses
`
`because a high elastic limit helps to sustain global and local loading with minimal or no
`
`permanent deformation of the metallic dental prostheses,
`
`this characteristic is absent in
`
`conventional metallic dental materials.
`4-....4911" “v.4 .
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`.
`I. piuauy ubcu 11 u iLcu p1
`
`For example, conventional metals and alloys
`
`elow 0.8 0/0.
`
`Accordingly, dental prosthesis made of bulk-solidifying amorphous alloys having an elastic
`
`strain limit of 1.5 % or higher, and preferably 1.8 % or higher is desired.
`
`The elastic limit of a material is also critical because metallic dental prostheses, such
`
`as the crowns and bridges discussed above, have highly intricate shapes and features, which
`
`must remain intact upon any mechanical loading both during preparation and in use. For
`
`example, because of the need to fit the crown and/or bridge as close to the tooth as possible,
`
`generally these prostheses have thin—walled shells as part of their overall shape and design. A
`
`material having a high elastic strain limit helps to keep both the general shape and intricate
`
`details of the metallic dental prostheses intact. In the case of conventional metals and alloys
`
`with much lower elastic strain limit, the use of thicker shells and larger structures are needed
`
`to sustain mechanical loading, as well as to maintain the integrity of the intricate details of
`
`the impression. Both thicker shells and larger structures are highly undesirable due to the
`
`increased operational and surgical complications. In addition, in some cases, these thicker
`
`shells and larger structures require that a larger section of the healthy tooth or teeth be cut
`
`away during operation in order to accommodate the crown or bridge in the patient.
`
`Secondly, bulk solidifying amorphous alloys can be readily cast from the molten state
`
`to replicate the very details of impression prepared for dental prosthesis. Indeed, Applicants
`
`have discovered that the low melting tempe. 111.65 of bul..-solidifiyi..g amorphous adoys
`
`provide a relatively easier casting operation such as reduced or minimal reaction with molds
`
`or investment shells. Further, the lack of any first-order phase transformation during the
`
`solidification of the bulk solidifying amorphous alloy reduces solidification shrinkage and as
`
`such provides a near—to-net shape configuration of the metallic dental prosthesis. The
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`solidification shrinkage is then dominated by the coefficient of thennal expansion rather than
`
`the volume difference between the solid and liquid state of the casting alloy. Accordingly,
`
`bulk amorphous alloys with low coefficient thermal expansion (at temperatures from ambient
`
`to glass transition) are preferred. For example,. Zr—base bulk solidifying amorphous alloys
`
`have generally a coefficient of thermal expansion of around 10'5 (m/m °C) providing low
`
`shrinkage rates. This is extremely important in the production of metallic dental prostheses
`
`since many of the intricate portions of the impressions can be lost if significant post-cast
`
`processing is required.
`
`In addition, bulk-solidifying amorphous alloys keep their fluidity to
`
`10
`
`exceptionally low temperatures, such as down to the glass transition temperature, compared
`
`to other dental casting materials, and especially those materials which exhibit the necessary
`
`yield strengths for use in metallic dental prosthesis applications. Accordingly, bulk—
`
`solidifying amorphous alloys with glass transition temperatures lower than 400 °C, and most
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`15
`
`preferably lower than 300 °C are preferred. For example, Zr-Ti base bulk—solidifying
`
`amorphous alloys have typical glass transition temperatures in the range of 320 °C to 450 °C
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`depending on the alloy composition.
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`Applicants have discovered that these characteristics combined with the lack of any
`
`microstructure allow bulk—solidifying amorphous alloys to replicate the intricacies of the
`
`impressions in a dental casting with exceptional quality. The casting characteristics of bulk—
`
`solidifying amorphous alloys not only reduce the post-cast finishing processes, but also
`
`provide a better surface finish and preparation due to reduced or minimal defects arising from
`
`the initial casting operation. For example, a dental prosthesis constructed of a bulk-
`
`solidifying amorphous alloy can be given a very high polish and surface smoothness which
`
`helps to hinder bacteria growth in the mouth. Further, the high polish and other surface
`
`smoothness characteristics can be desirable from an aesthetic perspective as well.
`
`While the above discussion has focussed primarily on the high elastic limit and
`
`castability properties of bulk-solidifying amorphous alloys, it should be understood that it is
`
`the unique combination of properties that makes these materials particularly suitable for use
`
`in metallic dental prostheses. For example the bulk—solidifying amorphous alloys described
`
`herein exhibit a very high hardness c
`
`and inert properties which leads to improved corrosion resistance over conventional
`
`materials. For example, Zr-base bulk-solidifying amorphous alloys have hardness values
`
`ranging from 4.0 GPa up to 6.0 GPa. In addition, the yield strength of the bulk-solidifying
`
`amorphous alloys is exceptionally high, especially compared to the crystalline alloys of their
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`base metals (e.g., Zr/Ti base amorphous alloys have typical yield strengths on the order of
`
`1.5 to 2.0 GPa). Such properties, a hardness value of greater than 4.0 GPa and preferably
`
`more than 5.0 GPa, along with the very high elastic strain limit of 1.2 % , preferably 1.5 %,
`
`and most preferably 1.8 % or higher, makes metallic dental prostheses of bulk—solidifying
`
`amorphous alloys highly durable. Moreover, because of the excellent castability of these
`
`materials the desired mechanical and physical properties of bulk-solidifying amorphous
`
`alloys are readily obtained in an as-cast condition. This is generally not true for conventional
`
`metals and alloys which are often not available at all as castings.
`
`Although the above discussion has focussed solely on choosing a bulk-solidifying
`
`amorphous alloy material based on certain advantageous physical properties,
`
`the bulk
`
`solidifying "11 1 nous -
`
`Al or Be in order to address the high sensitivity or allergic reactions of specific population
`
`groups to such metals.
`
`The invention is also directed to a method of manufacturing the metallic dental
`
`prostheses of the invention. Principally the bulk-solidifying amorphous alloys are fabricated
`
`by various casting methods. For example, in one exemplary embodiment, as shown in Figure
`
`1, a feedstock of bulk solidifying amorphous alloy composition is provided (step 1). This
`
`feedstock does not to have to be in amorphous phase. Then in a second step (step 2) the
`
`feedstock alloy is heated into the molten state above the melting temperature of bulk-
`
`solidifying amorphous alloy. Then in a third step (step 3) the molten alloy is fed into the mold
`
`having the shape of the desired dental prosthesis. After, the complete fill of the mold is
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`assured,
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`the mold is immersed into a quenching bath (step 4) to form a substantially
`
`amorphous atomic structure. The casting of bulk amorphous alloy is then removed from the
`
`mold to apply other post-cast finishing processes such as polishing (step 5).
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`The provided bulk solidifying amorphous alloy is such that, it has a critical cooling
`
`rate of less than 1,000 °C/sec, so that a section having a thickness greater than 0.5 m can be
`
`readily cast into an amorphous structure during the fabrication of dental prosthesis. However,
`
`more preferably, the critical cooling rate is less than 100 °C/sec and most preferably less than
`--
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`10 °C/sec. In one pre-..rred embodiment of t.-e invention, t e denta nr s‘rhesis is cast by
`
`providing a bulk-solidifying amorphous alloy having a coefficient of thermal expansion of
`
`less than about 10'5 (m/m °C), and a glass transition temperature of less than 400 °C, and
`
`preferably less than 300 °C, in order to achieve a high level of replication of the prosthesis
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`mold features after casting.
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`In a preferred embodiment, the molten amorphous alloy is superheated well above the
`
`melting temperature by 100 °C or more. This will provide higher fluidity and will allow the
`
`molten alloy to flow a much longer time before solidification. This is especially preferred in
`
`cases where the dental prosthesis has a very high aspect ratio (i.e. long and skinny shapes),
`
`and/or highly intricate shapes are to be duplicated.
`
`In another preferred embodiment, the feedstock alloy is heated to the molten state
`
`under an inert atmosphere and preferably under vacuum.
`
`Regardless of the actual casting method used, the mold itself can be prepared by
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`10
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`various methods and preferably by an investment-cast method.
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`In addition, various
`
`mechanisms can be utilized to feed the molten alloy into the mold. For example, gravity-
`
`d,
`
`though other mechanisms previ
`
`pressure are preferred. Such mechanisms can use centrifugal forces and/or inert gas pressure.
`
`Finally, various configurations of alloy feeding can be utilized, such as bottom—feeding.
`
`Another feeding method comprises counter-gravity feeding and casting, in such a method the
`
`feeding method is preferably carried outwith vacuum suction assistance.
`
`Although specific embodiments are disclosed herein,
`
`it
`
`is expected that persons
`
`skilled in the art can and will design metallic dental prostheses and methods of making such
`
`devices that are Within the scope of the following description either literally or under the
`
`Doctrine of Equivalents.
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`WHAT IS CLAIMED IS:
`
`1.
`
`A dental prosthesis comprising a bulk—solidifying amorphous alloy having an
`
`elastic strain limit of around 1.2% or more.
`
`5
`
`2.
`
`The dental prosthesis as described in claim 1, wherein the bulk bulk—
`
`solidifying amorphous alloy is described by the following molecular formula: (Zr,Ti)a(Ni,Cu,
`
`Fe)b(Be,Al,Si,B)c, wherein “a” is in the range of from about 30 to 75, “b” is in the range of
`
`from about 5 to 60, and “c” in the range of from about 0 to 50 in atomic percentages
`
`The dental prosthesis as described in claim 1, wherein the bulk-solidifying
`nnALm-l
`n
`1
`n
`1n +
`+'
`1
`1‘
`Ha
`P 11
`'
`-
`UUu Du 0
`u_y
`Luv
`nus
`1y
`"U"L “ '
`iOuG‘WW‘
`formula.
`"
`‘3
`"
`den 11
`
`”110y’
`
`is
`
`10 ecular
`
`3.
`
`amorhous
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`(Zr)a(I\Ib,Ti)b(Ni,Cu)c(Al)d, where a is in the range of from 45 to 65, b is in the range of from
`
`0 to 10, c is in the range of from 20 to 40, and d in the range of from 7.5 to 15 in atomic
`
`percentages.
`
`4.
`
`A dental prosthesis as described in claim 1, wherein the bulk—solidifying
`
`amorphous alloy has an elastic strain limit of around 1.8% or more.
`
`5.
`
`The dental prosthesis as described in claim 1, wherein the bulk-solidifying
`
`amorphous alloy has a high fracture toughness of at least about 10 ksi-\/in.
`
`6.
`
`The dental prosthesis as described in claim 1, wherein the bulk—solidifying
`
`amorphous alloy has a coefficient of thermal expansion of around 10'5 (m/m °C) or less.
`
`7.
`
`The dental prosthesis as described in claim 1, wherein the bulk-solidifying
`
`amorphous alloy has a high hardness value of at least about 4 Gpa.
`
`8.
`
`The dental prosthesis as described in claim 1, wherein the bulk-solidifying
`
`amorphous alloy has a high hardness value of at least about 5.0 GPa.
`
`9.
`
`The dental prosthesis as described in claim 1, wherein the bulk-solidifying
`
`amorphous alloy is based on ferrous metals.
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`10.
`
`The dental prosthesis as described in claim 9, wherein the bulk—solidifying
`
`amorphous alloy has a hardness of about 7.5 Gpa and higher.
`
`11.
`
`The dental prosthesis as described in claim 1, wherein the bulk-solidifying
`
`amorphous alloy has a glass transition temperature lower than 400 °C.
`
`12.
`
`The dental prosthesis 1 as described in claim 1, wherein the bulk-solidifying
`
`amorphous alloy further comprises a ductile metallic crystalline phase precipitate.
`
`11
`
`.
`
`LA)
`
`a
`ar
`A LLU
`
`S.i.
`e
`
`1 p
`
`amorphous alloy is Al free.
`
`14.
`
`The dental prosthesis as described in claim 1, wherein the bulk-solidifying
`
`amorphous alloy is Ni free.
`
`15.
`
`The dental prosthesis as described in claim 1, wherein the bulk-solidifying
`
`amorphous alloy is Be free.
`
`16.
`
`The dental prosthesis as described in claim 1, wherein at least a portion of the
`
`prosthesis is constructed of a conventional dental material.
`
`17.
`
`The dental prosthesis as described in claim 1, wherein the dental prosthesis is
`
`coated with a biocompatible resin cement.
`
`18.
`
`The dental prosthesis as described in claim 17, wherein the cement
`
`is
`
`reinforced with a metal primer agent and an oxide selected from the group consisting of
`
`alumina, magnesia, zirconia, and a combination of these oxides.
`
`19.
`
`The dental prosthesis as described in claim 1, wherein the at least one portion
`
`formed from the bulk-solidifying amorphous alloy has a section thickness of at least 0.5 mm.
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`20.
`
`The dental prosthesis as described in claim 1, wherein the dental prosthesis is
`
`in the form of one of either a bridge or a cap.
`
`21.
`
`A method of manufacturing a dental prosthesis comprising:
`
`providing a feedstock of a bulk-solidifying amorphous alloy;
`
`heating the feedstock to above the melting temperature of the bulk solidifying
`
`amorphous alloy to form a molten alloy;
`
`shaping the molten alloy to form a near-to-net shape dental prosthesis; and
`
`quenching the dental prosthesis at a cooling rate sufficient to ensure that the bulk
`
`solidifying amorphous alloy has a substantially amorphous atomic structure having an elastic
`"and“ 1:w.:+ A
`nu. am Lllllll. u
`
`22.
`
`The method as described in claim 21, wherein the step of heating includes
`
`superheating the feedstock to a temperature at
`
`least 100 °C higher than the melting
`
`temperature of the bulk solidifying amorphous alloy.
`
`23.
`
`The method as described in claim 21, wherein the step of heating is conducted
`
`in an inert environment.
`
`24.
`
`The method as described in claim 21, wherein the step of heating is conducted
`
`under a vacuum.
`
`25.
`
`The method as described in claim 21, wherein the bulk-solidifying amorphous
`
`alloy is described by the following molecular formula: (Zr,Ti)a(Ni,Cu, Fe)b(Be,Al,Si,B)c,
`
`wherein “a” is in the range of from about 30 to 75, “b” is in the range of from about 5 to 60,
`
`and “C” in the range of from about 0 to 50 in atomic percentages
`
`26.
`
`The method as described in claim 21, wherein the bulk—solidifying amorphous
`
`stanti 11y by the f llowing n1
`
`olecular
`
`ormula:
`
`(Zr)a (Nb,Ti)mfi
`
`(Ni,Cu)c(Al)d, Where a is in the range of from 45 to 65, b is in the range of from O to 10, c is
`
`in the range of from 20 to 40, and d in the range of from 7.5 to 15 in atomic percentages.
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`27.
`
`The method as described in claim 21, wherein the bulk-solidifying amorphous
`
`alloy has a coefficient of thermal expansion of around 10'5 (In/m °C) or less.
`
`28.
`
`The method as described in claim 21, wherein the bulk-solidifying amorphous
`
`alloy further comprises a ductile metallic crystalline phase precipitate.
`
`29.
`
`The method as described in claim 21, wherein the bulk-solidifying amorphous
`
`alloy is based on ferrous metals having a hardness of about 7.5 Gpa and higher.
`
`30.
`
`The method as described in claim 21, wherein the bulk—solidifying amorphous
`
`alloy has a glass transrtion temneratare lower than 400 °C.
`
`31.
`
`The method as described in claim 21, wherein a portion of the dental
`
`prosthesis is constructed of a conventional dental material.
`
`32.
`
`The method as described in claim 21, fiirther com