PTAB

PGR2025-00054

Straumann USA LLC v. Smart Denture Conversions LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Screw-Attached Pick-Up Dental Coping System And Methods
  • Brief Description: The ’781 patent relates to a dental system used for installing a dental prosthesis. The system includes a temporary fastener designed to secure a coping to an implant abutment during an impression or "pick-up" procedure. The key feature is that the temporary fastener can be threaded into the abutment for stability but is configured to be removed by a direct axial pulling force without being unscrewed.

3. Grounds for Unpatentability

Ground 1: Obviousness of System with Asymmetric Threads - Claims 10, 12, 15, and 16 are obvious over Bernhard in view of Poovey and Gracco.

  • Prior Art Relied Upon: Bernhard (Application # US 2017/0202649), Poovey (Application # US 2016/0045290), and Gracco (a 2012 journal article).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Bernhard disclosed a dental system with all the basic components, including a coping, an abutment, and a definitive screw, but used a temporary snap-fit or friction-fit connection for the pick-up process. Poovey taught a temporary impression coping screw with flexible threads made of a pliable material (e.g., plastic or silicone) that could be threaded in for stability but then "pulled out without much force" and without unscrewing. Gracco taught that using an asymmetric buttress thread shape on a miniscrew resulted in a "significant reduction in pullout force" compared to other thread designs, making it easier to remove via an axial pull.
    • Motivation to Combine: A POSITA would combine these references to improve Bernhard’s system. Petitioner asserted a POSITA would have been motivated to replace Bernhard's less stable snap-fit connector with a more secure and reliable threaded temporary fastener, as taught by Poovey. To ensure the threaded fastener could still be easily pulled out (a key feature of both Bernhard's and Poovey's temporary connectors), the POSITA would have been motivated to use an asymmetric buttress thread as taught by Gracco, which was known to reduce pull-out resistance while maintaining a secure threaded connection.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because the combination involved applying known techniques (flexible threads, buttress thread geometry) to a known system (Bernhard's) to achieve predictable results (a stable yet easily removable temporary fastener).

Ground 2: Obviousness of System with Split-Post Structure - Claims 1-9, 11, 13, and 14 are obvious over Bernhard in view of Poovey, Gracco, and Derey.

  • Prior Art Relied Upon: Bernhard (Application # US 2017/0202649), Poovey (Application # US 2016/0045290), Gracco (a 2012 journal article), and Derey (WO 2013/030839).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground built upon the combination of Bernhard, Poovey, and Gracco. Petitioner added Derey, which disclosed a temporary fastener for dental impressions having a split-post structure with two deflecting legs. These legs were designed to grip the internal threads of an implant but would "surrender their grip" and deflect inwardly when an upward pulling force was applied, allowing the fastener to be easily detached.
    • Motivation to Combine: A POSITA would have been motivated to further modify the temporary fastener from Ground 1 by incorporating Derey's split-post design. This modification would create an open space or slot in the fastener's shaft, resulting in a non-continuous thread pattern and providing a clear, reliable mechanical structure for the fastener to deform (deflect) upon removal. This would make it even easier to pull the fastener out of the abutment, a primary goal of such devices. The use of a high-strength polymer like PEEK for such deflecting legs was also taught in the art (e.g., Bernhard).
    • Expectation of Success: A POSITA would have had a reasonable expectation of success in designing a split-post fastener, as the technology was predictable and well within the ordinary skill in the art.

  • Additional Grounds: Petitioner also asserted that claims were unpatentable under 35 U.S.C. §112. Specifically, Ground 1 argued claims 6 and 10-16 are indefinite, and Ground 2 argued claims 1-16 lack adequate written description and enablement.

4. Key Technical Contentions (Beyond Claim Construction)

  • Claim Scope Exceeds Specification's Disclosure (§112(a)): Petitioner argued that the full scope of the independent claims was not supported by the written description or enabled by the specification. The petition contended that the ’781 patent disclosed only a single embodiment that achieved pull-out functionality: a fastener with a combination of asymmetric buttress threads and a split-post structure with deflecting legs. However, the claims were drafted much more broadly to cover any temporary fastener that (1) has any thread pattern different from the definitive screw's threads and (2) can be released by any axial force mechanism, not just one with a split-post. Petitioner argued this meant the patent owner did not possess or enable the full, broad scope of the invention as claimed.
  • Indefiniteness (§112(b)): Petitioner argued that key claim limitations were indefinite. Claim 6 allegedly used purely functional language ("configured to release") at the point of novelty without reciting the specific structure that achieves this function. Further, the limitation "does not essentially match" in claims 10-16 was argued to be indefinite because the specification's definition ("± 10 percent") provided no guidance on which thread parameters (e.g., angle, depth, contour) to compare, rendering the boundary of the claim scope unclear to a POSITA.

5. Relief Requested

  • Petitioner requested the institution of a Post Grant Review and cancellation of claims 1-16 of Patent 12,156,781 as unpatentable.