PTAB

IPR2017-00082

Straumann Mfg Inc v. ZirCore LLC

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1. Case Identification

2. Patent Overview

  • Title: Mass Custom Manufacturing of Dental Crowns and Crown Components
  • Brief Description: The ’031 patent relates to a method for manufacturing multi-component dental restorations using a CAD/CAM system. The method purports to improve upon conventional, iterative processes by using data from a single scan to create a virtual model of a final tooth shape, storing that model and related data in a "single master electronic file," and utilizing that file to manufacture two or more restoration components from end-stage materials.

3. Grounds for Unpatentability

Ground 1: Claim 1 is obvious over Hamada.

  • Prior Art Relied Upon: Hamada (Patent 6,832,877).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued Hamada anticipates or renders obvious claim 1 by disclosing a "Dental Measuring and Machining System" for multi-component restorations. Hamada taught performing a single scan of a physical model to create three-dimensional measurement data. This data was used in a CAD system to design a virtual model of the final prosthesis shape and its multiple components. Petitioner asserted that Hamada explicitly disclosed transmitting all data necessary for manufacturing—including the virtual model—to a remote machining site in a "single file" as an email attachment. This single file was then used by a CAM system to manufacture multiple components, such as the inner crown, outer crown, and veneer of a "double crown" prosthesis, from materials like titanium, which Petitioner contended were end-stage materials.
    • Motivation to Combine (for §103 grounds): As this was primarily an anticipation argument framed as obviousness, Petitioner argued any minor differences would have been obvious implementations. For example, to the extent machining multiple components was not explicit, a POSITA would have been motivated to use all available data in the transmitted file to automate the manufacturing process as much as possible.
    • Expectation of Success (for §103 grounds): Success was expected because it involved using the disclosed system for its intended purpose of manufacturing a complete dental prosthesis.

Ground 2: Claims 1-2 are obvious over Duret '022, Duret '288, Harrison, and Kellstrom.

  • Prior Art Relied Upon: Duret '022 (Patent 5,092,022), Duret '288 (Patent 4,611,288), Harrison (Patent 6,611,725), and Kellstrom (Patent 6,088,625).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that the combination of Duret ’022 and Duret ’288 (the "Duret Combination") taught a CAD/CAM method for producing multi-component dental prostheses from a single scan. The Duret Combination disclosed creating a virtual model of the final tooth shape ("envelope") and using it to manufacture components, such as the inner metal base and outer ceramic cap of a "ceramo-metallic crown." However, the Duret references did not explicitly disclose storing the design data in a single file. Petitioner argued that the secondary references, Harrison and Kellstrom, taught that storing data for multi-component "assemblies" in a single "assembly document" or master file was a standard and well-known practice in CAD/CAM systems at the time.
    • Motivation to Combine (for §103 grounds): A POSITA would combine the Duret Combination with the teachings of Harrison and Kellstrom to gain the known benefits of efficiency and data consolidation. Implementing Duret's dental manufacturing system using the standard single-file data structure for assemblies taught by Harrison and Kellstrom was an obvious and predictable design choice. Kellstrom further motivated writing "all assembly data to a data file for transmission" to a CAM system, directly corresponding to the method of the ’031 patent.
    • Expectation of Success (for §103 grounds): A POSITA would have had a high expectation of success, as this combination merely applied a conventional data management technique from general CAD/CAM arts (Harrison and Kellstrom) to a specific CAD/CAM application (Duret's dental system).

Ground 3: Claims 1-2 are obvious over Hamada in view of Duret '022.

  • Prior Art Relied Upon: Hamada (Patent 6,832,877) and Duret '022 (Patent 5,092,022).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground specifically targeted the "collateral component" limitation of claim 2 and the corresponding alternative limitation in claim 1[h]. Petitioner acknowledged that Hamada primarily described manufacturing restoration components via direct milling. Duret '022, in contrast, explicitly taught that its system could be used to machine either a prosthesis directly or a "mold for making a prosthesis." A mold is a type of "collateral component."
    • Motivation to Combine (for §103 grounds): A POSITA would combine Hamada with Duret ’022 because it was well-known that dental components could be made either by direct milling or by using a mold. Duret '022 presented these as simple alternatives. Therefore, a POSITA would have found it obvious to modify Hamada's system to use its "single file" to manufacture a mold (a collateral component) as an alternative to direct milling, which was merely a matter of design choice.
    • Expectation of Success (for §103 grounds): Success was expected because the combination involved substituting one known manufacturing technique (molding, from Duret '022) for another (direct milling, from Hamada) within an existing, functional system.

  • Additional Grounds: Petitioner asserted alternative obviousness challenges (Grounds 4 and 5) that were substantively identical to Grounds 1 and 3, respectively, but relied on Hamada’s published PCT application (Hamada/PCT, WO 01/091664) instead of the Hamada patent to serve as a priority date hedge.

4. Key Claim Construction Positions

  • "single master electronic file": For purposes of the IPR, Petitioner adopted the Patent Owner's proposed construction from parallel litigation: "a single collection of data for use by a computer program." Petitioner argued this construction supported its invalidity arguments, as the file disclosed in Hamada and the "assembly document" in Harrison both met this definition.
  • "collateral component": Petitioner argued this term meant "a peripheral piece, such as a mold, that is used to make a final piece that mates together with other components of a restoration." This construction was central to Ground 3, which relied on Duret '022's disclosure of making molds to meet the limitations of claim 2.

5. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1-2 of Patent 8,751,031 as unpatentable.