PTAB

IPR2025-00956

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 ’992 patent describes a dental system for installing a dental prosthesis. The system uses a temporary screw with specific thread characteristics to align and hold a coping to an implant abutment during an impression-taking "pick-up" procedure, where the screw is designed to be pulled out axially without being unscrewed.

3. Grounds for Unpatentability

Ground 1: 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 is valid prior art because the challenged claims are not entitled to their priority date (see Section 4 below). Petitioner contended that Kofford discloses every element of the challenged claims. Specifically, Kofford’s temporary screw embodiment shown in its Figure 75, which includes a post with asymmetric buttress threads and a slot creating deflecting legs, anticipates the claimed system. This embodiment is described as a temporary fastener that is inserted rotationally but can be extracted by an axial separation force, releasing both the coping and screw from the abutment, which maps directly to the limitations of independent claims 1 and 9.
    • Key Aspects: Petitioner asserted that dependent claims are also anticipated, citing Kofford’s disclosure of a torque driver (claim 2), asymmetric threads (claim 3), a polymeric and hollow screw (claim 4), reduced thread contact area (claim 5), and a split-post structure that deflects inwardly (claim 8).

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

  • Prior Art Relied Upon: Kofford (Patent 11,311,354) and Poovey (Application # 2016/0045290).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed claims requiring the temporary screw to be made of a polymer (claims 4, 12) and for its threads to deform during release (claim 7). Petitioner argued that while Kofford suggests a polymer screw, Poovey explicitly teaches making a temporary screw from a flexible material like silicone or plastic. Poovey’s screw is designed so its flexible threads can be pulled out of an implant without unscrewing.
    • Motivation to Combine: A POSITA would combine Kofford’s pull-out screw design with Poovey’s teaching of using a flexible polymer to make the screw easier to pull out. Poovey’s disclosure that flexible threads deform to allow for low-resistance removal provides the motivation to ensure Kofford’s screw functions as intended.
    • Expectation of Success: Petitioner contended a POSITA would have a high expectation of success in making Kofford’s screw from a polymer, as it is a predictable application of known materials to improve a known function (axial extraction).

Ground 3: 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 (Application # 2016/0045290), and Gracco (a 2012 article in Amer. J. Orthodontics & Dentofacial Orthopedics).

  • Core Argument for this Ground:

    • Prior Art Mapping: Bernhard disclosed a dental system with all the core components: a coping, an abutment with a threaded bore, and a definitive screw for permanent attachment. For temporary attachment, Bernhard taught using a snap-fit or friction-fit connection. Poovey taught replacing such temporary connections with a threaded temporary screw having flexible threads that can be pulled out axially. Gracco taught that an asymmetric buttress thread design significantly reduces the pullout force required for a screw compared to symmetric or reverse-buttress threads.
    • Motivation to Combine: A POSITA would have been motivated to replace Bernhard's less stable snap-fit temporary connection with a more secure threaded temporary screw, as taught by Poovey, to increase stability during the impression procedure. To ensure this new temporary screw could be easily pulled out as desired, a POSITA would look to known thread designs. Gracco explicitly taught that an asymmetric buttress thread geometry reduces resistance to axial removal, motivating its application to Poovey’s flexible screw within Bernhard’s system.
    • Expectation of Success: The combination involved substituting known elements (a pull-out threaded screw for a snap-fit connector) and applying a known design principle (buttress threads for easier removal) to achieve a predictable improvement in a known system.

  • Additional Grounds: Petitioner asserted additional challenges, including that claims 7 and 10 are anticipated by Kofford. Further obviousness grounds were asserted for claims 4 and 8 over Bernhard, Poovey, Gracco, and Derey (WO 2013/030839), and for claim 2 over Bernhard, Poovey, Gracco, and Ruetschi (DE 3808238).

4. Key Technical Contentions

  • Challenged Claims Lack Priority Support, Making Kofford Prior Art: A central contention of the petition was that claims 1-12 of the ’992 patent are not entitled to the filing date of their parent or provisional applications. Petitioner argued this is because the final claims are significantly broader than what was disclosed in those priority documents, which described only a single embodiment.
    • Unsupported "Different Thread" Scope: The priority applications allegedly disclosed only one type of "different" thread for the temporary screw: an asymmetric buttress thread. The issued claims, however, cover any thread pattern or profile that is different from the definitive screw, a scope Petitioner argued is not enabled or described by the limited disclosure.
    • Unsupported "Release" Scope: The priority applications allegedly disclosed that the pull-out function was enabled by two features working together: the buttress threads and deflecting legs created by a split-post structure. The issued claims removed the requirement for a split-post structure, claiming any axial force release mechanism, which Petitioner argued lacks written description support in the priority documents.

5. Relief Requested

  • Petitioner requests the Board institute an inter partes review of claims 1–12 of the ’992 patent, find the claims unpatentable, and cancel the claims.