PTAB

IPR2025-00956

Straumann USA, LLC v. Smart Denture Conversions, LLC.

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1. Case Identification

2. Patent Overview

  • Title: Screw-Attached Pick-Up Dental Coping System And Methods
  • Brief Description: The ’992 patent relates to a system and components for installing a dental prosthesis. The invention centers on a "temporary screw" used to secure a dental coping to an implant abutment during an impression-taking procedure, which features a thread pattern different from the final "definitive screw" and is designed to be removed by a straight pull-out force without being unscrewed.

3. Key Technical Contentions (Beyond Claim Construction)

  • Petitioner’s central technical-legal argument was that the ’992 patent is not entitled to the filing date of its priority applications. The consequence of this argument is that the patent’s effective filing date becomes June 3, 2023, which renders the Patent Owner’s own parent patent, Kofford (Patent 11,311,354, issued April 26, 2022), as prior art under 35 U.S.C. §102.
  • Petitioner asserted this lack of priority is based on inadequate written description support for the full scope of the challenged claims, for two primary reasons:
    • The claims broadly recite a temporary screw with threads "shaped differently" from the definitive screw, but the priority applications allegedly only described a single embodiment: a temporary screw with a specific "asymmetric" buttress thread.
    • The claims broadly recite that the temporary screw is released by an "axial force," but the priority applications allegedly only described a specific release mechanism involving a split-post structure with deflecting legs, failing to support other release mechanisms.

4. Grounds for Unpatentability

Ground 1: Anticipation by Kofford - Claims 1-6, 8-9, and 11-12 are anticipated by Kofford.

  • Prior Art Relied Upon: Kofford (Patent 11,311,354).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Kofford, established as prior art due to the ’992 patent’s alleged loss of priority, discloses every limitation of the challenged claims. Specifically, Petitioner mapped the embodiment shown in Kofford’s Figure 75 to the claims. This embodiment is a temporary screw with an asymmetric buttress thread pattern (different from the definitive screw’s symmetric pattern) and a slot creating a split-post structure. This structure allows the screw to be engaged via rotation but subsequently removed by a direct axial pull-out force, which Petitioner contended anticipates the limitations of independent claims 1 and 9. Petitioner further argued that Kofford discloses the features of the dependent claims, including the asymmetric thread pattern (claim 3), a hollow portion created by the slot (claim 4), and deflecting portions that move inwardly upon axial force (claim 8).

Ground 2: Obviousness over Kofford and Poovey - Claims 4, 7, and 12 are obvious over Kofford in view of Poovey.

  • Prior Art Relied Upon: Kofford (Patent 11,311,354), Poovey (Application # 2016/0045290).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground began with the temporary screw system disclosed in Kofford. Petitioner then cited Poovey for its teaching of temporary dental screws made from, or coated with, a flexible and pliable material like plastic or silicone (a polymer). Poovey teaches that this construction allows the screw’s threads to be flexible enough to be pulled out of an implant with low resistance.
    • Motivation to Combine: A person of ordinary skill in the art (POSA) would combine the teachings to modify Kofford's temporary screw by making it from a polymer, as taught by Poovey. The motivation was to make the screw easier to pull out, a known problem with a known solution. This modification would result in a polymeric screw (as required by claim 12) whose threads would necessarily deform upon release (as required by claim 7).
    • Expectation of Success: A POSA would have a high expectation of success, as making a screw from a flexible polymer to facilitate pull-out removal is a predictable technology.

Ground 3: Obviousness over Bernhard, Poovey, and Gracco - Claims 1, 3, 5-7, and 9-12 are obvious over Bernhard in view of Poovey and Gracco.

  • Prior Art Relied Upon: Bernhard (Application # 2017/0202649), Poovey (’290 application), Gracco (Amer. J. Orthodontics & Dentofacial Orthopedics (2012)).

  • Core Argument for this Ground:

    • Prior Art Mapping: Bernhard was presented as the base system, disclosing a dental implant system with a definitive screw for permanent attachment and a temporary snap-fit or friction-fit connector for holding a coping during a pick-up process. Poovey teaches using a temporary screw with flexible threads that can be pulled out. Gracco is a study demonstrating that an asymmetric buttress thread shape significantly reduces the required pull-out force compared to other designs.
    • Motivation to Combine: A POSA would replace Bernhard's temporary snap-fit connector with a threaded temporary screw (as taught by Poovey) to provide a more secure and stable temporary connection. To ensure this screw could still be easily removed by a pull-out force (the goal of both Bernhard's snap-fit and Poovey's screw), the POSA would be motivated to optimize the thread design. Gracco's teaching that an asymmetric buttress thread facilitates easier axial removal would have made it an obvious design choice.
    • Expectation of Success: The combination was argued to be a straightforward application of known techniques to a known system to achieve predictable results.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including that claims 4 and 8 are obvious over Bernhard, Poovey, Gracco, and Derey (adding the teaching of a split-post structure with deflecting legs), and that claim 2 is obvious over Bernhard, Poovey, Gracco, and Ruetschi (adding the teaching of a torque-limiting driver).

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-12 of Patent 11,937,992 as unpatentable.