DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Continued Examination Under 37 CFR 1.114A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on (1 – 14 – 2026) has been entered.
Response to Arguments
Applicant's arguments and remarks filed (1 – 14 – 2025) have been fully considered but they are not persuasiveApplicant argues…
Vollmann in view of MacDougald/Ritzberger, Heinz and Ceramic does not teach a glass ceramic blank with lithium metasilicate as main crystal phase (i.e. the glass ceramic blank from step (c) as defined in claim 1) is compacted by hot pressing at a temperature of from 650 to 780 °C and at a pressure of from 5 to 50 MPa (as defined in step (d) of claim 1) to prepare a glass ceramic blank for dental purposes with lithium silicate as main crystal phase (as defined in the preamble of claim 1).
It would not have been obvious to replace the pressureless sintering to full density as described by Vollmann by hot pressing at a temperature of from 650 to 780°C and at a pressure of from 5 to 50 MPa as required by step (d) of claim 1.
Vollmann as modified by Heinz describes hot pressing of glass ceramic materials at a temperature of from 700 to 1200°C and a pressure of from 1 to 4 MPa (cf. US 2010058588 A1, paragraphs [0094], [0095] and [0109]). Accordingly, none of these references teaches hot sintering at a pressure of from 5 to 50 MPa as required by step (d) of claim 1. Moreover, given that Vollmann itself notes that already the conditions of the pressureless sintering to full density at a temperature in the range between 750°C and 950°C cause the crystals of a glass ceramic blank to be partly melted (cf. US 2019099244 A1, paragraph [0029]), a skilled person would not seriously contemplate replacing the pressureless sintering of Vollmann by hot pressing as described for glass ceramic materials by MacDougald, Ritzberger or Heinz, let alone by hot isostatic pressing (HIP) as described for other ceramic materials in Ceramic Industry.
Ceramic Industry does not relate to glass ceramics, let alone lithium silicate glass ceramics. Instead, this reference relates to classic ceramic materials such as nitrides, carbides, borides, spinels, etc. (cf. Ceramic Industry, 2nd paragraph under the subheading "Material Properties")
Vollmann in view of MacDougald/Ritzberger, Heinz and Ceramic Industry fail to teach or suggest a process in which differently coloured powders of lithium silicate glasses, or suspensions of differently coloured powders of lithium silicate glasses in liquid media, are introduced into a mould in a controlled manner comprising a suitably controlled mixing of the powders or suspensions to achieve a continuous change in the composition of the mixture introduced into the mould and thus generating a continuous colour gradient. In particular, the disclosure of Vollmann relied on by the Examiner merely describes that a cavity (18) is formed within a first ceramic material (14) and filled with a differently colored second ceramic material (20) (cf. US 2019099244 A1, paragraph [0075]). The process thus described results in the two ceramic materials being deposited next to each other, but does not involve any mixing of these materials, let alone the generation of a continuous color gradient. This is further corroborated by Fig. 1C of Vollmann, which shows that the first ceramic material (14) and the second ceramic material (20) are clearly separated at the border of the cavity (18) without any mixing. This will result in a sudden change in color at the border of the cavity (18) forming the interface between the two ceramic materials, rather than the formation of a continuous color gradient as required by claim 1.
Vollmann in view of MacDougald/Ritzberger, Heinz and Ceramic Industry fail to teach or suggest that the claimed process provides blanks that comprise homogeneously distributed lithium silicate crystals as the main crystal phase. The claimed process surprisingly obtains glass ceramics exhibiting a very homogeneous distribution of crystals, i.e., a homogeneous distribution that is comparable to glass ceramics produced by crystallizing monolithic glass blocks, even from glass ceramic powder compacts. This advantageous effect of the claimed process is not taught or suggested in the prior art.
Vollmann in view of MacDougald/Ritzberger, Heinz and Ceramic Industry Claim 8 further specifies that the hot pressing in step (d) is effected at a temperature from 700 to 750°C and at a pressure of from 10 to 30 MPa. For analogous reasons as explained above with regard to claim 1, Vollmann in view of MacDougald/Ritzberger, Heinz and Ceramic Industry fail to teach or suggest a process in which a glass ceramic blank with lithium metasilicate as main crystal phase (i.e. the glass ceramic blank from step (c) as defined in claim 1) is compacted by hot pressing at a temperature of from 700 to 750°C and at a pressure of from 10 to 30 MPa. In particular, none of the cited reference contemplates hot pressing at a pressure of from 10 to 30 MPa.
Vollmann in view of MacDougald/Ritzberger, Heinz and Ceramic Industry, Claim 11 further specifies that the obtained multi-coloured glass ceramic blank has lithium metasilicate as main crystal phase. Vollmann in view of MacDougald/Ritzberger, Heinz and Ceramic Industry fail to teach or suggest a process in which a glass ceramic blank is compacted by hot pressing to provide a glass ceramic blank that has lithium metasilicate as main crystal phase. As explained above, Vollmann does not mention hot pressing. MacDougald and Ceramic Industry do not mention lithium metasilicate. Both Ritzberger (cf. US2014135202A1, paragraph [0092]) and Heinz (cf. US2010058588A1, paragraph [0110]) teach that hot pressing results in lithium metasilicate being converted into lithium disilicate. Therefore, even when considered in combination, the references relied on by the Examiner cannot render the subject matter of claim 11 obvious.
Applicant further argues that none of the other applied references make up for the deficiency of Vollmann / Vollmann as modified.
This is not found to be persuasive because…
, b.) & c.) As noted in the action of (8 – 14 – 2025) MacDougald states on ([0040]) that a densification step may follow the binder removal step. This may be conducted by thermal treatment (e.g., sintering), hot pressing, hot isostatic pressing, reaction bonding, directed metal oxidation, reaction infiltration, chemical vapor deposition and combinations thereof. As such, MacDougald discloses the use of thermal treatment (e.g., sintering) in combination with hot pressing / hot isostatic pressing. Namely, MacDougald teaches that densification may be accomplished by several equivalent means including via thermal treatment (e.g., sintering), hot pressing, hot isostatic pressing and combinations thereof. Thus, MacDougald provides for interchangeably using sintering, hot pressing, hot isostatic pressing, and combinations thereof as means to achieve densification of the lithium disilicate ceramic article. Accordingly, the application of a known technique to a known device (method, or product) ready for improvement to yield predictable results and/or “Obvious to try” – choosing from a finite number of identified, predictable solutions, with a reasonable expectation of success and/or the simple substitution of one known element for another to obtain predictable results provides for the recitation of KSR case law. Where, "A person of ordinary skill has good reason to pursue the known option within his or her technical grasp. If this leads to the anticipated success, it is likely the product not of innovation but of ordinary skill and common sense." KSR int'l Co. v. Teleflex Inc., 127 S. Ct. 1727, 82 USPQ2d 1385 (2007), MPEP 2143.
& c.) While examiner agrees that Heinz describes hot pressing of glass ceramic materials at a temperature of from 700 to 1200 °C and a pressure of from 1 to 4 MPa, with a pressure of from 1 to 4 MPa slightly below applicant range of 5 to 50 MPa, Heinz notes that the pressure utilized for pressing the viscous lithium silicate material under a pressure of about 1 to 4 MPa into a mould or dye to obtain the dental restoration with a desired geometry. Where about 4 MPa is understood to be close but not overlapping 5 MPa. Accordingly, the case law for close but not overlapping ranges may be recited. Where, a prima facie case of obviousness exists where the claimed ranges and prior art ranges do not overlap but are close enough that one skilled in the art would have expected them to have the same properties, see Titanium Metals Corp. of America v. Banner, 778 F.2d 775,227 USPQ 773 (Fed. Cir. 1985), MPEP 2144.
Applicant arguments which are directed towards the types of materials Ceramic Industry (CI) mentions i.e., Material systems include silicon nitrides, silicon carbides, boron nitride, boron carbide, titanium boride, spinels, etc. is found under the Cold isostatic pressing (CIP) heading. Which examiner did not rely upon, instead examiner relied upon details for the Hot Isostatic Pressing (HIP). Adding, while examiner agrees that Ceramic Industry (CI) does not mention lithium silicate. CI was not relied upon to teach conditions for Hot Isostatic Pressing (HIP) which has been established by MacDougald on ([0040]) to be an equivalent densification process to pressureless sintering to fabricate a lithium silicate article.
As noted in the previous action Vollman teaches on ([0075]) teaches that once the cavity 18 is formed (FIG. 1b), the press plunger 16 is removed and a second ceramic material 20 filled into the cavity 18, which largely corresponds in its composition to that of the first material with the limitation that the percentage of coloring substances deviates, so that a desired tooth color is achieved since the dentin of the tooth to be produced is derived from the second ceramic material 20. As such, the introduced of material into the mould is understood to transpire in a controlled manner, i.e., layered such that a mixing of the powders or suspensions transpires to achieve a continuous change in the composition of the mixture introduced into the mould and forming a continuous colour gradient across the article fabricated. Namely, the layering of materials in a mold to form a color gradient involves the combining or putting together (mixing) of individual layers in a mold to from a single substance. Highlighting, there is no requirement that the mixture be homogeneous in nature as the mixture is understood to provide a continuous colour gradient across the article fabricated.
Applicant’s argument relies upon newly amended features found in the preamble. In particular, wherein the multi-colored glass ceramic blank comprises homogenously distributed lithium silicate crystals as the main crystal phase… As such, applicant’s arguments rely on language solely recited in preamble recitations in claim(s) 1. When reading the preamble in the context of the entire claim, the recitation wherein the multi-colored glass ceramic blank comprises homogenously distributed lithium silicate crystals as the main crystal phase is not limiting because the body of the claim describes a complete invention, and the language recited solely in the preamble does not provide any distinct definition of any of the claimed invention’s limitations. Thus, the preamble of the claim(s) is not considered a limitation and is of no significance to claim construction. See Pitney Bowes, Inc. v. Hewlett-Packard Co., 182 F.3d 1298, 1305, 51 USPQ2d 1161, 1165 (Fed. Cir. 1999). See MPEP § 2111.02. Furthermore, as noted in Vollman in ([0051]) that a dental restoration, in particular tooth, crown or partial crown, is characterized by comprising a first layer of a first ceramic material which extends on the incisal side and a root-side-extending second layer consisting of a second ceramic material, in that the first layer has a higher translucency and that the first layer differs in color from the second layer. As such, the entire composition is understood to comprise a single material, i.e., lithium silicate glass ceramic, (Abstract) with only the coloring pigment of the second material, i.e, lithium silicate glass being different. Thus, providing for and producing a multi-colored glass ceramic blank comprises homogenously distributed lithium silicate crystals as the main crystal phase as recited in the newly amended limitation within the preamble of the claim.
As detailed, CI teaches that that The hot isostatic pressing (HIP) process applies high pressure (50-200 MPa) and high temperature (400-2,000°C) to the exterior surface of parts via an inert gas (e.g., argon or nitrogen). The elevated temperature and pressure cause sub-surface voids to be eliminated through a combination of plastic flow and diffusion. As such, the amount of pressure implemented is understood to impact the elimination of sub-surface voids, resulting in the pressure being a result effective variable. Accordingly, the case law for result effective variable may be recited. Where, it is well settled that determination of optimum values of cause effective variables such as these process parameters is within the skill of one practicing in the art. In re Boesch, 205 USPQ 215 (CCPA 1980). In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977), MPEP 2143 II (B).
As noted claim 11 requires that the multi- coloured glass ceramic blank has lithium metasilicate as a main crystal phase. With Vollman teaching on ([0028]) that lithium metasilicate and lithium disilicate crystals are formed as the main crystal phases. Noting, that as claim it is not required that metasilicate be the only / exclusive main crystal phase present.
This is unpersuasive because as explained above there was not found to be deficiency in Vollmann / Vollmann as modified.
Claim Objections
Claim(s) 1 – 2 & 4 – 20 is/are objected to because of the following informalities:
Currently claim 1 reads in the preamble “Process for the preparation of a multi- coloured glass ceramic blank for dental purposes, wherein the multi-coloured glass ceramic blank comprises homogeneously distributed with lithium silicate crystals as main crystal phase….” But goes on to read “…the glass blank from step (a) or (b) is heat treated to obtain a glass ceramic blank with lithium metasilicate as main crystal phase…”. While, Lithium silicate is a general term, while lithium metasilicate (Li₂SiO₃) is a specific, common form of it for the purpose of claim consistency implement the single lithium metasilicate (Li₂SiO₃) throughout for the purposes of claim consistency.
Currently claim 11 reads “In which the multi-coloured glass ceramic blank has lithium metasilicate as main crystal phase.“ Currently the term main crystal phase is missing an i.e, the a, an, etc, article prior to the phrase.
Appropriate correction is required.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
A.) Claim(s) 1 – 2, 4 – 8, 11, 13 – 15 & 17 – 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Vollman et al. (DE 102016119934 A1, with Translation Provide by US 20190099244 A1, hereinafter Vollman) in view of MacDougald et al. (US 20040245663 A1, hereinafter MacDougald) in view of Heinz et al. (US 20100058588 A1, hereinafter Heinz) and in further view of Ceramic Industry (Hot and Cold Isostatic Pressing of Ceramics, 2017, hereinafter CI)Regarding claim 1,
Process for the preparation of a multi- coloured glass ceramic blank for dental purposes, wherein the multi-coloured glass ceramic blank comprises homogeneously distributed with lithium silicate crystals as main crystal phase, in which
(a) (i) differently coloured powders of lithium silicate glasses or (ii) suspensions of differently coloured powders of lithium silicate glasses in liquid media are introduced into a mould to form a glass blank,
wherein the powders or suspensions are introduced into the mould in a controlled manner comprising a suitably controlled mixing of the powders or suspensions to achieve a continuous change in the composition of the mixture introduced into the mould and thus generating a continuous colour gradient
(b) optionally the glass blank from step (a) is compacted by pressing,
(c) the glass blank from step (a) or (b) is heat treated to obtain a glass ceramic blank with lithium metasilicate as main crystal phase, and[AltContent: rect]
(d) the glass ceramic blank from step (c) is compacted by hot pressing at a temperature of from 650 to 780 °C and
at a pressure of from 5 to 50 MPa.
Vollmann teaches the following:
& c.) ([0011]) teaches a layer of pourable material is first introduced into a die. After introducing the powder, an open cavity is created, e.g., B (see, Fig. 1) . formed by means of a press stamp. ([0012]) teaching that a second ceramic material is then introduced into this cavity or recess and the materials are then pressed together. ([0016]) teaches a second open cavity is formed in the second ceramic material and a third ceramic material is introduced into it, its composition should deviate from that of the second ceramic material, in particular also have a lower translucency than the second or first material. ([0019]) expanding on this stating that coloring of the ceramic materials to the desired extent, in particular in such a way that a cutting material is used for the first area, which is more translucent and less colored compared to the second ceramic material. As such a continuous color gradient is understood to be formed in the ceramic dental blank formed. ([0031]) teaches a composition of the starting glass material. ([0067]) teaches that a first ceramic material 14 is prepared consisting of a lithium silicate glass ceramic.
([0075]) teaches that once the cavity 18 is formed (FIG. 1b), the press plunger 16 is removed and a second ceramic material 20 filled into the cavity 18, which largely corresponds in its composition to that of the first material with the limitation that the percentage of coloring substances deviates, so that a desired tooth color is achieved since the dentin of the tooth to be produced is derived from the second ceramic material 20. As such, the introduced of material into the mould is understood to transpire in a controlled manner such that a mixing of the powders or suspensions transpires to achieve a continuous change in the composition of the mixture introduced into the mould and forming a continuous colour gradient across the article fabricated.
([0027]) teaches that the blank may be first fully sintered to then produce the molded body. ([0038]) teaches preferably multi-stage heat treatment referred to in connection with the crystallization firing can be carried out here. ([0039]) teaches a further heat treatment can then be carried out for relaxation. ([0028]) teaches that lithium metasilicate and lithium disilicate crystals are formed as the main crystal phases. ([0097]) Adding that it should be noted that the proportion of lithium silicate crystals in the first and second ceramic materials should be in the range between 10 and 80% by volume. As such, lithium silicate / lithium metasilicate is understood to be the main crystal phase (X > 50% by volume).
Regarding Claim 1, Vollmann is silent on implementing hot pressing. In analogous art for formation of lithium silicate materials which can be easily processed by machining to form dental products, MacDougald suggests details regarding implementing a hot pressing on the lithium silicate as a means for sintering and/or shaping the final product, and in this regard MacDougald teaches the following:
([0040]) teaches that a densification step may follow the binder removal step. This may be conducted by thermal treatment (e.g., sintering), hot pressing, hot isostatic pressing, reaction bonding, directed metal oxidation, reaction infiltration, chemical vapor deposition and combinations thereof. ([0040]) adding that after a machining step the restoration 84 may be further subjected to a post fabrication treatment such as cold isostatic pressing or hot isostatic pressing to facilitate the removal of any residual internal voids, delamination or other defects.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann. By implementing a hot-pressing technique in conjunction with sintering and/or a hot-pressing technique after a machining step, as taught by MacDougald. Highlighting, one would be motivated to implement hot-pressing in conjunction with sintering as it provides for a known means for densification for glass-ceramics such as lithium silicate and/or implementation of a hot isostatic pressing step after machining step provides for the removal of any residual internal voids, delamination or other defects, ([0040]). Where, the use of known technique to improve similar devices (methods, or products) in the same way and/or the application of a known technique to a known device (method, or product) ready for improvement to yield predictable results. Accordingly, "A person of ordinary skill has good reason to pursue the known option within his or her technical grasp. If this leads to the anticipated success, it is likely the product not of innovation but of ordinary skill and common sense." KSR int'l Co. v. Teleflex Inc., 127 S. Ct. 1727, 82 USPQ2d 1385 (2007).
Regarding Claim 1, Vollmann as modified by MacDougald is silent on implementing a hot pressing on the lithium silicate. In analogous art as applied above in claim 1, Heinz suggests details regarding implementing a hot pressing on the lithium silicate as a means for sintering and/or shaping the final product, and in this regard, Heinz teaches the following:
([0109]) teaches that the hot pressing comprises subjecting the lithium silicate material to a heat treatment at a temperature of about 500 to 1200 °C to convert the lithium silicate material into a viscous state and pressing the viscous lithium silicate material under a pressure of about 1 to 4 MPa into a mould or dye to obtain the dental restoration with a desired geometry.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified by MacDougald. By further augmenting the fabrication process to utilize a hot-pressing temperature of about 500 to 1200 °C and pressure of about 1 to 4 MPa, as taught by Heinz. Highlighting, one would be motivated to implement a hot-pressing with a temperature of about 500 to 1200 °C and pressure of about 1 to 4 MPa provides for a dental restoration with a desired geometry, ([0109]). Highlighting, while about 1 to 4 MPa is slightly below applicant’s range of 5 to 50 MPa. The case law for close but not overlapping ranges may be recited. Where, a prima facie case of obviousness exists where the claimed ranges and prior art ranges do not overlap but are close enough that one skilled in the art would have expected them to have the same properties, see Titanium Metals Corp. of America v. Banner, 778 F.2d 775,227 USPQ 773 (Fed. Cir. 1985), MPEP 2144.
Regarding Claim 1, Vollmann as modified by MacDougald and Heinz is silent on implementing an optimized pressure for hot pressing of the lithium silicate. In analogous art for hot pressing of ceramic materials, CI suggests details regarding implementing an optimized pressure for hot pressing of ceramic materials as a means for increasing their density, and in this regard, CI teaches the following:
(¶1) teaches that the HIP process applies high pressure (50 – 200 MPa) and high temperature (400 – 2,000 °C) to the exterior surface of parts via an inert gas (e.g., argon or nitrogen). The elevated temperature and pressure cause sub-surface voids to be eliminated through a combination of plastic flow and diffusion. The challenge is to reach the highest possible theoretical density while maintaining productivity goals.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified by MacDougald and Heinz. By further augmenting the hot pressing with an optimized pressure in the range provided, and as taught by CI. Highlighting, one would be motivated to implement an optimized pressure range for hot pressing as it provides for an increase in density which leads to the elimination of internal porosity for defect healing of castings and longer lifetime of HIPed parts, (¶7, Increase in Density).
Regarding claim 2 as applied to claim 1,
In which in step (a) the powders are introduced into the mould and step (b) is carried out.
Vollmann teaches the following:
([0023]) teaches that in order to produce a dental molding, according to the invention a blank is used which consists of pressed lithium silicate glass ceramic powder. ([0033]) adds that the lithium silicate glass ceramic powder materials produced according to the explanations above are then inserted into the die or press mold filled.
Regarding claim 4 as applied to claim 1,
In which in step (a) the powders or suspensions are introduced into the mould in such a way that the multi-coloured glass ceramic blank prepared has a continuously changing colour.
Vollmann teaches the following:
([0011]) teaches a layer of pourable material is first introduced into a die. After introducing the powder, an open cavity is created, e.g. B (see, Fig. 1) . formed by means of a press stamp. ([0012]) teaching that a second ceramic material is then introduced into this cavity or recess and the materials are then pressed together. ([0016]) teaches a second open cavity is formed in the second ceramic material and a third ceramic material is introduced into it, its composition should deviate from that of the second ceramic material, in particular also have a lower translucency than the second or first material. ([0019]) expanding on this stating that coloring of the ceramic materials to the desired extent, in particular in such a way that a cutting material is used for the first area, which is more translucent and less colored compared to the second ceramic material. As such a continuous color gradient is understood to be formed in the ceramic dental blank formed.
Regarding claim 5 as applied to claim 1,
In which in step (a) the powders (i) have a particle size of from 0.5 to 150 µm and/or an average particle size as D50 value of from 5 to 30 µm, or
the powders of the suspensions (ii) have a particle size of from 0.5 to 80 µm and/or
an average particle size as D50 value of from 5 to 30 µm.
Vollmann teaches the following:
([0030]) teaches that the glass or glass particle powders are particularly those that have a grain size between 1 µm and 150 µm.
Highlighting, that this limitation is understood to be optional if (a) or (c) is satisfied.
Highlighting, while this limitations has been restricted out. ([0105]) teaches that a powder with a mean grain size between 1 μm and 150 μm, in particular between 10 μm and 30 μm.Highlighting, if applicant does not agree with the interpretation provided above. A secondary rejection is provided below.
Regarding claim 5 as applied to claim 1,
In which in step (a) the powders (i) have a particle size of from 0.5 to 150 µm and/or an average particle size as D50 value of from 5 to 30 µm, or
the powders of the suspensions (ii) have a particle size of from 0.5 to 80 µm and/or
an average particle size as D50 value of from 5 to 30 µm.
Vollmann teaches the following:
([0030]) teaches that the glass or glass particle powders are particularly those that have a grain size between 1 µm and 150 µm.
Highlighting, that this limitation is understood to be optional if (a) or (c) is satisfied.
Highlighting, while this limitations has been restricted. ([0105]) teaches that a powder with a mean grain size between 1 μm and 150 μm, in particular between 10 μm and 30 μm,
Regarding Claim 5, Vollmann is silent on implementing a suspension and the size of the particles in the suspension. In analogous art as applied above in claim 1, MacDougald suggests details regarding implementing suspension of the lithium silicate as a means molding material, and in this regard MacDougald teaches the following:
(Claim 24) teaches mixing ceramic powder and one or more media together to achieve homogeneity throughout the mixture. ([0020]) teaches that the size of the particles is in the range of about 0.5 to about 50 microns and preferably in the range of about 1 to about 3 microns for crystalline ceramics such as alumina and from about 5 to about 20 microns for glass-ceramics such as lithium silicate-based glass ceramics. With both ranges mentioned falling within the range specified in the claim for particles in suspension.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann. By modifying the composition to include a suspension with a particle size in the range of 0.5 to about 50 μm, as taught by MacDougald. Highlighting, modifying the composition to include a suspension with a particle size in the range of 0.5 to about 50 μm provides for little or no porosity in the sintered product and the particles being of uniform particle size achieves good particle packing, ([0020]).
Regarding claim 6 as applied to claim 1,
In which in step (b) the pressing is effected at a temperature of less than 600 °C, and
at a pressure of from 20 to 120 MPa.
Vollmann teaches the following:
& b.) ([0058]) teaches the pressing process, namely pressing to form a cavity in the first material followed by filling the cavity with a second material, (see Fig. 2), and while no temperature is directly mentioned it is understood to transpire at room temperature (25 °C), which is less than 600 °C. With ([0059]) teaching that pressing is preferably carried out at a pressure between 50 MPa and 400 MPa. As such, step (b) the pressing is effected at a temperature less than 600 °C, i.e. room temperature (25 °C) and at a pressure of from 20 to 120 MPa, namely 50 MPa and 400 MPa.
Regarding claim 7 as applied to claim 1,
In which in step (c) the heat treatment is effected at a temperature of less than 700 °C and for a period of from 2 to 60 min.
Vollmann teaches the following:
([0015]) teaches if binder is present - debinding and pre-sintering or initial sintering take place at a temperature between 650 ° C and 760 ° C for a time between 10 minutes and 40 minutes. Additionally, ([0021]) teaches that the sintering is carried out over a time between 5 minutes and 120 minutes in a temperature range between 750 ° C and 950 ° C. Highlighting, that ([0021]) teaches that the sintering temperature impacts the degree of crystallization. As such, the case law for result effective variable may be recited regarding the impact of sintering temperature on the degree of crystallization of the lithium silicate glass ceramic fabricated. Where, it is well settled that determination of optimum values of cause effective variables such as these process parameters is within the skill of one practicing in the art. In re Boesch, 205 USPQ 215 (CCPA 1980). Highlighting, if applicant does not agree with the interpretation provided above. A secondary rejection is provided below.
Regarding claim 7 as applied to claim 1,
In which in step (c) the heat treatment is effected at a temperature of less than 700 °C and for a period of from 2 to 60 min.
Vollmann teaches the following:
([0015]) teaches if binder is present - debinding and pre-sintering or initial sintering take place at a temperature between 650 ° C and 760 ° C for a time between 10 minutes and 40 minutes. Additionally, ([0021]) teaches that the sintering is carried out over a time between 5 minutes and 120 minutes in a temperature range between 750 ° C and 950 ° C. Highlighting, that ([0021]) teaches that the sintering temperature impacts the degree of crystallization. As such, the case law for result effective variable may be recited regarding the impact of sintering temperature on the degree of crystallization of the lithium silicate glass ceramic fabricated. Where, it is well settled that determination of optimum values of cause effective variables such as these process parameters is within the skill of one practicing in the art. In re Boesch, 205 USPQ 215 (CCPA 1980).
Regarding Claim 7, Vollmann also teaching that the crystallization and dense sintering can transpire at the same time, ([0021]). Vollmann is silent on implementing an optimized temperature for the heat treatment. In analogous art as applied above in claim 1, MacDougald suggests details regarding implementing an optimized heat treatment temperature, and in this regard MacDougald teaches the following:
([0028]) teaches that binder burnout is at 300 to about 1000° C and more preferably from about 400 to about 800° C. ([0028]) adding this followed by sintering which may be carried out at about 600° to about 1400° C.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann. By implementing an optimized heat treatment temperatures in the ranges suggested above, and as taught by MacDougald. Highlighting, implementing an optimized heat treatment temperature range provides for ceramic blank that is ready or nearly ready to receive veneering porcelain or similar coating, ([0028]).
Regarding claim 8 as applied to claim 1,
In which in step (d) the hot pressing is effected at a temperature of from 700 to 750 °C and
at a pressure of from 10 to 30 MPa.
Regarding Claim 8, Vollmann as modified by MacDougald is silent on implementing a hot pressing on the lithium silicate. In analogous art as applied above in claim 1, Heinz suggests details regarding implementing a hot pressing on the lithium silicate as a means for sintering and/or shaping the final product, and in this regard, Heinz teaches the following:
& b.) ([0109]) teaches that the hot pressing comprises subjecting the lithium silicate material to a heat treatment at a temperature of about 500 to 1200 °C to convert the lithium silicate material into a viscous state and pressing the viscous lithium silicate material under a pressure of about 1 to 4 MPa into a mould or dye to obtain the dental restoration with a desired geometry.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified by MacDougald. By further augmenting the process to utilize a hot-pressing temperature of about 500 to 1200 °C and pressure of about 1 to 4 MPa, as taught by Heinz. Highlighting, one would be motivated to implement a hot-pressing with a temperature of about 500 to 1200° C and pressure of about 1 to 4 MPa provides for a dental restoration with a desired geometry, ([0109])Regarding Claim 8, Vollmann as modified by MacDougald and Heinz is silent on implementing an optimized pressure for hot pressing of the lithium silicate. In analogous art for hot pressing of ceramic materials, CI suggests details regarding implementing an optimized pressure for hot pressing of ceramic materials as a means for increasing their density, and in this regard, CI teaches the following:
& b.) (¶1) teaches that the HIP process applies high pressure (50 – 200 MPa) and high temperature (400 – 2,000°C) to the exterior surface of parts via an inert gas (e.g., argon or nitrogen). The elevated temperature and pressure cause sub-surface voids to be eliminated through a combination of plastic flow and diffusion. The challenge is to reach the highest possible theoretical density while maintaining productivity goals. As such, the amount of pressure implemented is understood to impact the elimination of sub-surface voids, resulting in the pressure being a result effective variable.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified by MacDougald and Heinz. By further augmenting the process to include a hot pressing with an optimized pressure in the range provided, and as taught by CI. Highlighting, one would be motivated to implement a hot press with an optimized pressure range provides a for an increase in density which leads to the elimination of internal porosity for defect healing of castings and longer lifetime of HIPed parts, (¶7, Increase in Density). Accordingly, due to the pressure implemented impacting the elimination of sub-surface voids the case law for result effective variable may be recited. Where, it is well settled that determination of optimum values of cause effective variables such as these process parameters is within the skill of one practicing in the art. In re Boesch, 205 USPQ 215 (CCPA 1980). In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977), MPEP 2143 II (B).
Regarding claim 11 as applied to claim 1,
In which the multi-coloured glass ceramic blank has lithium metasilicate as main crystal phase.
Vollmann teaches the following:
([0021]) teaches that meta and disilicate crystals are formed as the main crystal phases.
Regarding claim 13 as applied to claim ,
In which the multi- coloured glass ceramic blank has a density of from 2.4 to 2.6 g/cm3.
Vollmann teaches the following:
([0067]) teaches that the density of the blank 28 after sealing sintering is approximately 2.6 g/cm3 or 635 > 99.9% of the theoretical final density.
Regarding claim 14 as applied to claim 1,
In which the multi- coloured glass ceramic blank comprises at least one of the following components in the amounts indicated:
Component wt.-%
SiO2 64.0 to 75.0
Li2O 13.0 to 17.0
K2O 0 to 5.0
A12O3 0.5 to 5.0
P2O5 2.0 to 5.0
Vollmann teaches the following:
([0023]) teaches SiO2 from 57.5 % to 60.5 %, which is slightly below the range specified.
([0023]) teaches LiO2 from 13.5 % to 20.5 %
It should be noted that the amount of K2O required encompass 0 %. As such, K2O is understood to be an optional component. However,([0023]) teaches K2O from 0.5 % 3.5 %
([0023]) teaches Al2O3 from 0.5 % to 6.0 %
([0023]) teaches P2O5 from 3.0 % to 7.5 %.
Regarding Claim 14, Vollmann as modified MacDougald is silent on implementing an optimized amount of SiO2 in the precursor starting material. In analogous art as applied above in claim 1, where the lithium silicate glass ceramic material of Heinz also comprises SiO2, Li2O, K2O, Al2O3 and P2O5 as the main components ([0034]), Heinz suggests details regarding implementing an optimized amount of SiO2 in the precursor starting material, and in this regard, Heinz teaches the following:
([0057]) teaches that the lithium silicate material as described above is particularly preferred which comprises 64.0 to 73.0 wt. % of SiO2.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified by MacDougald. By further modifying and optimizing amount of SiO2 in the precursor starting material of a lithium silicate glass ceramic material, as taught by Heinz, due to the fact it would amount to nothing more than a use of a known amount of SiO2 in the precursor starting material of a lithium silicate glass ceramic, for its intended use, in a known environment, to accomplish entirely expected result, as suggested by Heinz. Highlighting, that the use of known technique to improve similar devices (methods, or products) in the same way an/or the application a known technique to a known device (method, or product) ready for improvement to yield predictable results, allows for the recitation of KSR case law. Where, "A person of ordinary skill has good reason to pursue the known option within his or her technical grasp. If this leads to the anticipated success, it is likely the product not of innovation but of ordinary skill and common sense." KSR int'l Co. v. Teleflex Inc., 127 S. Ct. 1727, 82 USPQ2d 1385 (2007).
Regarding claim 15 as applied to claim 1,
In which the multi-coloured glass ceramic blank comprises at least one of the following components in the amounts indicated:
Component wt.-%
SiO2 64.0 to 75.0
Li2O 13.0 to 17.0
K2 O 0 to 5.0
A12O3 0.5 to 5.0
P2O5 2.0 to 5.0
ZrO2 0 to 5.0
MgO 0 to 5.0
SrO 0 to 5.0
ZnO 0 to 5.0
F 0 to 1.0
colouring and/or fluorescent components 0 to 10.0,
wherein the colouring and/or fluorescent components are selected from the group of oxides of Sn, Ce, V, Mn, Co, Ni, Cu, Fe, Cr, Tb, Eu, Er and Pr.
Vollmann teaches the following:
([0023]) teaches SiO2 from 57.5 % to 60.5 %, which is slightly below the range specified.
([0023]) teaches LiO2 from 13.5 % to 20.5 %
It should be noted that the amount of K2O required encompass 0 %. As such, K2O is understood to be an optional component. However,([0023]) teaches K2O from 0.5 % 3.5 %
([0023]) teaches Al2O3 from 0.5 % to 6.0 %
([0023]) teaches P2O5 from 3.0 % to 7.5 %.
& l.) It should be noted that the amount of coloring/fluorescent components required encompass 0 %. As such, the coloring/fluorescent components are understood to be an optional component. However, ([0050]) teaches at least (one) an additive 0 — 4 %. ([0051]) Adding, that the at least one additive is at least one additive from the group of color pigments and/or fluorescent agents. In particular, it is provided that the additive is at least one oxide from the group of rare earth metals or contains such an oxide. ([0081]) Specifying to use Tb2O3, and Er2O3 to influence the fluorescence and to use MnO, Fe2O3, , V2O3, CeO2 or other rare earth oxides for coloring.
Regarding Claim 15, Vollmann as modified by MacDougald is silent on implementing an optimized amount of ZrO2, MgO, SrO, ZnO and F to utilize in the precursor starting material. In analogous art as applied above in claim 1, where the lithium silicate glass ceramic material of Heinz also comprises SiO2, Li2O, K2O, Al2O3 and P2O5 as the main components ([0034]), Heinz suggests details regarding implementing an optimized amount of ZrO2, MgO, SrO, ZnO and F in the precursor starting material, and in this regard Heinz teaches the following:
([0057]) teaches that the lithium silicate material as described above is particularly preferred which comprises 64.0 to 73.0 wt. % of SiO2.
It should be noted that the amount of ZrO2 required encompass 0 %. As such, ZrO2 is understood to be an optional component. However,([0060]) teaches that ZrO2 from 0.0 % to 2.0 %
It should be noted that the amount of MgO required encompass 0 %. As such, MgO is understood to be an optional component. However,([0062]) teaches that MeIIO from 0 % to 7.0 %, with MeIIO being one or more members selected from the group consisting of CaO, BaO, SrO and MgO.
It should be noted that the amount of SrO required encompass 0 %. As such, SrO is understood to be an optional component. However,([0062]) teaches that MeIIO from 0 % to 7.0 %, with MeIIO being one or more members selected from the group consisting of CaO, BaO, SrO and MgO.
It should be noted that the amount of ZnO required encompass 0 %. As such, ZnO is understood to be an optional component. However, ([0062]) teaches that ZnO from 2.0 % to 6.0 %.
It should be noted that the amount of F required encompass 0 %. As such, F is understood to be an optional component. However,([0066]) teaches additional components may therefore be in particular compounds such as B2O3 and F which in general amount to 0 to 5.0% by weight.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified. By implementing an optimized amount of SiO2 in the precursor starting material of a lithium silicate glass ceramic material, as taught by Heinz. By implementing optimized amounts of ZrO2, MgO, SrO, ZnO and F in the precursor starting material, as taught by Heinz. Highlighting, adding optimized amounts of ZrO2, MgO, SrO, ZnO provides a means for adding components that allow for tailoring the coloring and fluorescent of the material fabricated, ([0039]). Furthermore, adding optimized amounts of F provides a means for enhancing the glass technical process, ([0026]). As such the amounts of ZrO2, MgO, SrO, ZnO and F are understood to impact the coloring/ fluorescent the material fabricated and tailoring the glass technical process, respectively. As such, the case law for result effective variable(s) may be recited regarding the impact of ZrO2, MgO, SrO, ZnO and F on the final material properties and processing. Where, it is well settled that determination of optimum values of cause effective variables such as these process parameters is within the skill of one practicing in the art. In re Boesch, 205 USPQ 215 (CCPA 1980).
Regarding claim 17 as applied to claim 1,
In which (i) the process according to claim 1 is carried out to produce a multi-coloured glass ceramic blank,
(ii) the multi-coloured glass ceramic blank is given the shape of the dental restoration by machining, and
(iii) at least one heat treatment at a temperature of more than 750 °C is carried out.
Vollmann teaches the following:
([0011]) teaches a layer of pourable material is first introduced into a die. After introducing the powder, an open cavity is created, e.g., B (see, Fig. 1) . formed by means of a press stamp. ([0012]) teaching that a second ceramic material is then introduced into this cavity or recess and the materials are then pressed together. ([0016]) teaches a second open cavity is formed in the second ceramic material and a third ceramic material is introduced into it, its composition should deviate from that of the second ceramic material, in particular also have a lower translucency than the second or first material. ([0019]) expanding on this stating that coloring of the ceramic materials to the desired extent, in particular in such a way that a cutting material is used for the first area, which is more translucent and less colored compared to the second ceramic material. As such a continuous color gradient is understood to be formed in the ceramic dental blank formed.
([0077]) teaches that the restorations to be manufactured, which are available as CAD data sets, are then positioned on and in the blank sections in order to carve the dentures out of the blank by milling and/or grinding.
([0021]) teaches that simultaneously with the sintering process or later, a crystallization firing can also be carried out in several temperature levels. ([0021]) going on to note that a second crystallization at 720°C – 780°C for approx. 10-60 mins. Noting that a third crystallization firing may also transpire. Highlighting, that the range of 720°C – 780°C is understood to overlap with applicant’s range of more than 750 °C.
Regarding claim 18 as applied to claim 17,
In which in step (iii) the heat treatment effects the formation of lithium disilicate as main crystal phase.
Vollmann teaches the following:
([0021]) teaches that crystallization/partial crystallization of lithium disilicate can be controlled via utilizing a tailored sintering process. Namely, that as temperatures rise crystallization goes from partial to full crystallization and that less time is needed at higher temperature to achieve / impact the crystallization/partial crystallization of lithium disilicate. As such, it is understood that the heat treatments impact the formation of lithium disilicate crystals. Highlighting, if applicant does not agree with the interpretation provided above. A secondary rejection is provided below.
Regarding claim 19 as applied to claim 17,
In which in step (ii) the machining is effected with computer- controlled milling and/or grinding devices
Vollmann teaches the following:
([0077]) teaches that the restorations to be manufactured, which are available as CAD data sets, are then positioned on and in the blank sections in order to carve the dentures out of the blank by milling and/or grinding.
Regarding claim 20 as applied to claim 17,
In which the dental restoration is selected from the group of crowns, abutments, inlays, onlays, veneers, facets, bridges and caps.
Vollmann teaches the following:
([0035]) teaches that the pre-sintered or through-sintered blank for use in producing a dental restoration, such as a dental framework, crown, partial crown, bridge, cap, veneer, abutment, post structure, in particular crown or partial crown, consisting of a ceramic material which has areas of different compositions.
B.) Claim(s) 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Vollman in view of MacDougald in view of Heinz in view of CI and in further view of Zhang et al. (Lithium Disilicate Glass-Ceramics by Heat Treatment, 2015, hereinafter Zhang)
Regarding claim 8 as applied to claim 1,
In which in step (d) the hot pressing is effected at a temperature of from 700 to 750 °C and
at a pressure of from 10 to 30 MPa.
Regarding Claim 8, Vollmann as modified by MacDougald is silent on implementing a hot pressing on the lithium silicate. In analogous art as applied above in claim 1, Heinz suggests details regarding implementing a hot pressing on the lithium silicate as a means for sintering and/or shaping the final product, and in this regard, Heinz teaches the following:
& b.) ([0109]) teaches that the hot pressing comprises subjecting the lithium silicate material to a heat treatment at a temperature of about 500 to 1200 °C to convert the lithium silicate material into a viscous state and pressing the viscous lithium silicate material under a pressure of about 1 to 4 MPa into a mould or dye to obtain the dental restoration with a desired geometry.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified by MacDougald. By further augmenting the process to utilize a hot-pressing temperature of about 500 to 1200 °C and pressure of about 1 to 4 MPa, as taught by Heinz. Highlighting, one would be motivated to implement a hot-pressing with a temperature of about 500 to 1200° C and pressure of about 1 to 4 MPa provides for a dental restoration with a desired geometry, ([0109])Regarding Claim 8, Vollmann as modified by MacDougald and Heinz and CI is silent on implementing an optimized pressure for hot pressing of the lithium silicate. In analogous art for hot pressing of ceramic materials including lithium silicate, Zhang suggests details regarding implementing an optimized pressure for hot pressing of ceramic materials, and in this regard Zhang, suggests teaches the following:
& b.) (Experimental Procedures, ¶2) teaches the prepared powdered was hot pressed at 760 °C for 60 min with pressure of 30 MPa under a low vacuum. This was followed by a heat treatment of the pressed rectangular bars. Noting, that (Abstract) clarifies that in this study, lithium disilicate glass-ceramic was fabricated through heat treatment of lithium metasilicate glass-ceramics obtained by hot pressing of glass powder at low temperature. The crystalline phase, microstructure, and mechanical properties were investigated. The results indicated that lithium metasilicate glass-ceramic with a relative density of higher than 99% was obtained after hot pressing. Furthermore, (Introduction, ¶1) notes that due to the low temperature of metasilicate formation, the hot-pressing temperature should be lower than the Li2Si2O5 formation temperature, which results in difficulty of achieving a high density for the outstanding translucency. As such, the hot-pressing temperature is understood to impact the high density for the outstanding translucency of the article fabricated. Accordingly, the hot-pressing temperature is understood to be a result effective variable that impacts the outstanding translucency of the article fabricated.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified by MacDougald and Heinz. By further augmenting the process to include a hot pressing with an optimized pressure in the range provided, and as taught by CI. Highlighting, one would be motivated to implement a hot press with an optimized pressure range provides a for an increase in density which leads to the elimination of internal porosity for defect healing of castings and longer lifetime of HIPed parts, (¶7, Increase in Density). Highlighting, while a temperature of 760 °C is understood to be slightly above applicant’s range accordingly, the case law for close but not overlapping range may be recited. Where, a prima facie case of obviousness exists where the claimed ranges and prior art ranges do not overlap but are close enough that one skilled in the art would have expected them to have the same properties, see Titanium Metals Corp. of America v. Banner, 778 F.2d 775,227 USPQ 773 (Fed. Cir. 1985), MPEP 2144. Furthermore, and as detailed above, the hot-pressing temperature is understood to be a result effective variable that impacts the outstanding translucency of the article fabricated. Accordingly, it is well settled that determination of optimum values of cause effective variables such as these process parameters is within the skill of one practicing in the art. In re Boesch, 205 USPQ 215 (CCPA 1980). In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977), MPEP 2143 II (B).
C.) Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Vollman in view of MacDougald in view of Heinz in view of CI and in further view of Huang et al. (Fabrication of a high-strength lithium disilicate glass-ceramic…,2013, hereinafter Huang)Regarding claim 9 as applied to claim 1,
In which in step (d) the hot pressing is effected for a period of from 0.1 to 10 min.
Regarding Claim 9, Vollmann as modified by MacDougald, Heinz and CI is silent on implementing an optimized holding time for hot pressing of the lithium silicate. In analogous art for hot pressing of ceramic materials, Huang suggests details regarding implementing an optimized holding time for hot pressing of ceramic materials as a means for increasing their density, and in this regard, Huang teaches the following:
(Pg. 49, 3.2.1 The effecting of the annealing stage, ((Fig. 5B) teaches that b) Set III samples annealed at various holding times of the second stage at 675 °C. Highlighting, that the range of holding times providing for hot pressing ranges from 15 mins to 2h. With (Pg. 51, 3.3.1 Phase Assemblage and Microstructure, Figs. 7 – 8) showing the impact of holding time on the flexural strength of the samples fabricated.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified by MacDougald, Heinz and CI. By further modifying and optimizing the holding time utilized for hot pressing of the lithium silicate article being fabricated, as taught by Huang. Highlighting, one would be motivated to implement an optimized holding time for hot pressing of the lithium silicate article as it provides a means for tailoring the microstructure, and flexural strength of the samples fabricated, (Pg. 51, 3.3.1 Phase assemblage and Microstructure, Figs. 7 – 8).
D.) Claim(s) 10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Vollmann in view of MacDougald in view of Heinz in view of CI and in further view of Vacuum Industries (Vacuum Hot Press Furnaces for Powder Compaction, 1982, hereinafter VI)Regarding claim 10 as applied to claim 1,
In which in step (d) the hot pressing is effected at an atmospheric pressure of less than 0.1 bar.
Regarding Claim 10, Vollmann also teaching that hot pressing can be used to shape the lithium silicate, ([0054]) and/or as an alternative to sintering, (0056]). Vollmann as modified by MacDougald, Heinz and CI is silent on implementing an optimized pressure for hot pressing of the lithium silicate. In analogous art for hot pressing of ceramic materials, VI suggests details regarding implementing an optimized pressure for hot pressing powdered ceramic materials, and in this regard VI teaches the following:
(Abstract) teaches that by applying a vacuum the surrounding environment can be controlled. Adding that a relatively easily attained vacuum level of 5 x 10-4 torr is equivalent to a residual impurity level of less than 1 ppm. Highlighting, that 5 x 10-4 torr is equivalent to 6.67 x 10-8 bar, which is less than 0.1 bar, i.e. X < 0.1 bar.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified by MacDougald, Heinz and CI. By further modifying the hot pressing of ceramic materials to include a vacuum of less than 0.1 bar i.e. replacement of traditional hot-pressing techniques with that of vacuum hot pressing for the fabrication of ceramic materials, as taught by VI. Highlighting, one would be motivated to implement a vacuum for hot pressing for the fabrication of ceramic materials with a vacuum pressure of less than 0.1 bar as it provides a means for tailoring and controlling the surrounding environment, (Abstract). Accordingly, the simple substitution of one known element for another to obtain predictable results and/or the use of known technique to improve similar devices (methods, or products) in the same way allows for the recitation of KSR case law. Where, "A person of ordinary skill has good reason to pursue the known option within his or her technical grasp. If this leads to the anticipated success, it is likely the product not of innovation but of ordinary skill and common sense." KSR int'l Co. v. Teleflex Inc., 127 S. Ct. 1727, 82 USPQ2d 1385 (2007).
E.) Claim(s) 11 – 12 & 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Vollmann in view of MacDougald in view of Heinz in view of CI and in further view of Ritzberger et al. (US 20140135202 A1, hereinafter Ritzberger)Regarding claim 11 as applied to claim 1,
In which the multi-coloured glass ceramic blank has lithium metasilicate as main crystal phase.
Regarding Claim 11, Vollmann as modified by Heinz and CI is silent on the heat treatment effects the formation of lithium disilicate as main crystal phase. In analogous art as applied above in claim 1, Ritzberger suggests details regarding the heat treatment effects the formation of lithium metasilicate as main crystal phase, and in this regard Ritzberger teaches the following:
([0086]) teaches that the heat treatment at a temperature of only 660 to 680 °C. resulted in the case of Examples 11 and 13 – 16 in the formation of glass ceramics with lithium metasilicate as main crystal phase.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified by Heinz and CI. By further augmenting the heat treatment to include a heat treatment at 660 to 680 °C, as taught by Ritzberger. Highlighting, one would be motivated to implement a heat treatment at 660 to 680 °C as it provides a means for forming lithium metasilicate as main crystal phase, ([0086]). Highlighting, that the use of known technique to improve similar devices (methods, or products) in the same way and/or the application a known technique to a known device (method, or product) ready for improvement to yield predictable results, allows for the recitation of KSR case law. Where, "A person of ordinary skill has good reason to pursue the known option within his or her technical grasp. If this leads to the anticipated success, it is likely the product not of innovation but of ordinary skill and common sense." KSR int'l Co. v. Teleflex Inc., 127 S. Ct. 1727, 82 USPQ2d 1385 (2007).
Regarding claim 12 as applied to claim 1,
In which the multi-coloured glass ceramic blank comprises more than 10 wt.-% lithium metasilicate crystals.
Regarding Claim 12, Vollmann also teaching that the amount of lithium silicate crystals comprises between 10 and 80% by vol. ([0097]). Vollmann as modified by Heinz and CI is silent on implementing an optimizing the amount of lithium silicate crystals that comprise the ceramic article fabricated. In analogous art as applied above in claim 1, Ritzberger suggests details regarding implementing an optimized amount of amount of lithium silicate crystals that comprise the ceramic article fabricated, and in this regard Ritzberger teaches the following:
([0046]) teaches that particular the glass ceramic comprises more than 10 vol.-%, preferably more than 20 vol.-% and particularly preferred more than 30 vol.-% lithium disilicate crystals, relative to the total glass ceramic. Where more than 30 vol.-% is understood to include 100 vol.-% which encompasses applicant’s range of more than 10 wt.-% lithium metasilicate crystals.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified by Heinz and CI. By further augmenting and optimizing the amount of lithium metasilicate crystals, as taught by Ritzberger. Highlighting, one would be motivated to implement an optimized amount of lithium metasilicate crystals as it provides for a means for tailoring the strength of the lithium silicate material fabricated, ([0049] –[0050]). Accordingly, the amount of lithium metasilicate crystals is understood to impact the strength of the lithium silicate material fabricated. As such, the case law for result effective variables may be recited. Where, it is well settled that determination of optimum values of cause effective variables such as these process parameters is within the skill of one practicing in the art. In re Boesch, 205 USPQ 215 (CCPA 1980).
Regarding claim 18 as applied to claim 17,
In which in step (iii) the heat treatment effects the formation of lithium disilicate as main crystal phase.
Regarding Claim 18, Vollmann as modified by Heinz and CI is silent on the heat treatment effects the formation of lithium disilicate as main crystal phase. In analogous art as applied above in claim 1, Ritzberger suggests details regarding the heat treatment effects the formation of lithium disilicate as main crystal phase, and in this regard Ritzberger teaches the following:
([0013]) teaches that the common to the known lithium disilicate glass ceramics is that they require heat treatments at more than 800 °C in order to affect the precipitation of lithium disilicate as main crystal phase. ([0065]) teaches that the temperature range for forming lithium disilicate is expanded from 700 °C to 800 °C.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified by Heinz and CI. By further augmenting the heat treatment to include a heat treatment at more than 800° C, as taught by Ritzberger. Highlighting, one would be motivated to implement a heat treatment at more than 800° C is it provides a means for forming lithium disilicate as main crystal phase from precursory lithium metasilicate, ([0065]). Highlighting, that the use of known technique to improve similar devices (methods, or products) in the same way an/or the application a known technique to a known device (method, or product) ready for improvement to yield predictable results, allows for the recitation of KSR case law. Where, "A person of ordinary skill has good reason to pursue the known option within his or her technical grasp. If this leads to the anticipated success, it is likely the product not of innovation but of ordinary skill and common sense." KSR int'l Co. v. Teleflex Inc., 127 S. Ct. 1727, 82 USPQ2d 1385 (2007).
F.) Claim(s) 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Vollmann in view of MacDougald in view of Heinz in view of CI and in further view of Nobbmann et al. (D90, D50, D10 and Span, 2016, hereinafter Nobbmann)Regarding claim 16 as applied to claim 1,
In which in step (a) the powders (i) and the powders (ii) have an average particle size as d50 value of from 10 to 20 µm.
Vollmann teaches the following
([0053]) teaches that the glass particle powders are particularly those that have a grain size between 1 µm and 150 µm.
Regarding Claim 16, Vollmann as modified teaches the majority of claim 1. Vollmann as modified is silent on implementing an optimized average particle size (D50). In analogous art for a discussion on particle size distributions and the roles that various parameters play in measuring the particle size distribution, Nobbmann suggests details regarding implementing an optimized average particle size (D50) and its impact on the Span of the distribution implemented, and in this regard Nobbmann teaches the following:
(What is the D90 (or D50, or D10), ¶2) teaches an additional parameter to show the width of the size distribution is the span. The span of a volume-based size distribution is defined as
S
p
a
n
=
(
D
90
–
D
10
)
D
50
which gives an indication of how far the 10 percent and 90 percent points are apart, normalized with the midpoint. As such, the average particle size (D50) is understood to impact the Span of the distribution provided, namely the larger the average particle size (D50), the smaller the Span of the distribution will be.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a dental blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a mold and wherein the materials are pressed and after pressing are sintered of Vollmann as modified. By optimizing the average particle size (D50) of the particles implemented, as taught by Nobbmann. Highlighting, augmenting the average particle size (D50) for the ceramic material implemented to be optimized, provides a means for tailoring the Span of the particle distribution utilized. Accordingly, the average particle size (D50) for the ceramic material is understood to impact Span of the particle distribution. As such, the case law for result effective variables may be recited. Where, It is well settled that determination of optimum values of cause effective variables such as these process parameters is within the skill of one practicing in the art. In re Boesch, 205 USPQ 215 (CCPA 1980). Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Ritzberger et al. (US 20160302898 A1) – teaches in the (Abstract) a lithium silicate glass ceramics and glasses containing specific oxides of hexavalent elements are described which crystallize at low temperatures and are suitable in particular as dental materials.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Andrés E. Behrens Jr. whose telephone number is (571)-272-9096. The examiner can normally be reached on Monday - Friday 7:30 AM-5:30 PM.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Alison Hindenlang can be reached on (571)-270-7001. The fax phone number for the organization where this application or proceeding is assigned is (571)-273-8300.
Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at (866)-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call (800)-786-9199 (IN USA OR CANADA) or (571)-272-1000.
/Andrés E. Behrens Jr./Examiner, Art Unit 1741/JaMel M Nelson/Primary Examiner, Art Unit 1743