PTAB

IPR2025-00821

ClearCorrect Operating LLC v. Align Technology Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Multilayer Polymer Sheets and Dental Appliances
  • Brief Description: The ’091 patent discloses multilayer polymer sheets for making orthodontic appliances, such as dental aligners. The claims are directed to appliances having a specific layered structure, typically a hard co-polyester "first layer" and a soft thermoplastic polyurethane (TPU) "second layer," with specified mechanical properties.

3. Grounds for Unpatentability

Ground 1: Obviousness over Kalili, Porter, and Texin 990R - Claims 6, 9, 18, 23, and 25-26 are obvious over Kalili in view of Porter and Texin 990R.

  • Prior Art Relied Upon: Kalili (Application # 2011/0020761), Porter (a December 2007 article in Plastics Technology magazine), and Texin 990R (a November 2002 product information sheet).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Kalili disclosed a two-layer dental aligner with a hard outer layer of polycarbonate and a soft inner TPU layer. The Texin 990R datasheet, a material explicitly mentioned in Kalili, was alleged to disclose a TPU with all the mechanical properties required for the claimed "second layer" (e.g., tensile strength > 5000 psi, elongation at break > 200%). Porter was presented as teaching the replacement of polycarbonate with Tritan copolyester, a material that allegedly meets all the mechanical properties required for the claimed "first layer" (e.g., flexural modulus > 150,000 psi).
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references to improve upon Kalili's design. The primary motivation asserted was to replace the polycarbonate in Kalili, which was known to release harmful Bisphenol-A (BPA), with the safer, BPA-free Tritan copolyester disclosed in Porter. Porter further motivated this substitution by teaching that Tritan offered superior chemical resistance and durability compared to polycarbonate.
    • Expectation of Success: Petitioner asserted a POSITA would have had a reasonable expectation of success because Tritan was proven for use in thermoforming processes and had a history of successfully replacing polycarbonate in the industry. The combination involved substituting one known material for another to gain predictable benefits (improved safety and durability).

Ground 2: Obviousness over Tadros, Porter, Kalili, and Texin 990R - Claims 1, 4-7, 9-13, 16-20, 22-23, and 25-26 are obvious over Tadros in view of Porter, Kalili, and Texin 990R.

  • Prior Art Relied Upon: Tadros (Application # 2005/0100853), Porter, Kalili, and Texin 990R.

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Tadros disclosed the foundational structure for many claims: a "soft-hard-soft" three-layer dental appliance. However, Tadros’s hard central layer used a polycarbonate-copolyester mixture. The proposed combination modifies Tadros by substituting its hard and soft layers with superior, known materials. Porter provided the Tritan copolyester to replace Tadros's hard layer, meeting the "first layer" limitations. Kalili and the Texin 990R datasheet provided the specific TPU to replace Tadros's generic soft elastomer layers, meeting the "second layer" limitations.
    • Motivation to Combine: A POSITA would be motivated to improve Tadros’s design for two primary reasons. First, to replace the BPA-containing hard layer in Tadros with the safer and better-performing Tritan from Porter. Second, to use the specific Texin 990R TPU from Kalili for the soft layers, as Kalili taught its "outstanding" properties (e.g., abrasive resistance, flexibility, comfort) made it ideal for dental aligners, a direct application of Tadros's invention.
    • Expectation of Success: Petitioner contended success was predictable because the combination involved substituting materials within an existing framework (Tadros's aligner) to achieve known benefits. Kalili and Tadros address identical subject matter, and using the specific, advantageous TPU from Kalili in Tadros's device was a logical design choice.

  • Additional Grounds: Petitioner asserted additional obviousness challenges based on the same core combinations but further in view of Wen (International Publication No. WO 2006/096558). Wen was cited for its teaching that replacing a single thick polymer layer with multiple thinner sublayers improves tooth conformity and interlayer bonding, which Petitioner argued would have made it obvious to create the claimed three- and four-layer configurations.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that the Board should not exercise discretionary denial under 35 U.S.C. §314(a). Petitioner stipulated that if the IPR is instituted, it will not pursue in the parallel district court case any invalidity ground that was raised or could have been reasonably raised in the petition.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-23 and 25-26 of the ’091 patent as unpatentable.