On August 10, 2026, the Federal Circuit vacated a Patent Trial and Appeal Board ("PTAB") decision that had invalidated a Dental Monitoring SAS patent as obvious. The court held that the Board applied the wrong legal standard in evaluating whether a prior art patent application was available as prior art against the Dental Monitoring SAS patent. Going forward, a challenger relying on the earlier date of a provisional application to establish a non-provisional application as prior art must show that the provisional actually describes, consistent with the 35 U.S.C. § 112 written description requirement, at least one claim of the non-provisional application.
Why It Matters
- For patent challengers: If you are relying on a reference that only qualifies as prior art because of the filing date of an earlier provisional filing, you must show the provisional actually describes the invention in the detail required by 35 U.S.C. § 112 — not just that it is procedurally linked to the later application through a priority claim.
- For patent owners: This decision gives you a new tool to defeat prior art references that depend on an earlier provisional filing date. It is now clear that mere procedural or “ministerial” compliance with priority-claiming formalities is not enough and the substance of the provisional must support at least one of the later application's claims.
- For everyone monitoring PTAB practice: This decision resolves an open question left by the Board's earlier Penumbra decision, which adopted a more permissive standard for determining whether a non-provisional application, for prior art purposes, is entitled to the filing date of an earlier provisional application. The PTAB’s more permissive approach in Penumbra is no longer good law on this issue.
Background
Dental Monitoring owns U.S. Patent No. 10,755,409 (hereinafter, “the ‘409 patent”), which covers a method of using a “deep learning device” to analyze dental images and guide a patient or dentist to capture a better photo when needed. Align Technology filed an inter partes review ("IPR") petition challenging the patent's claims as obvious over three references, including a U.S. Patent Application Publication 2021/0068923A1 ("Carrier").
Because the non-provisional application of Carrier was filed after the ‘409 patent, while the provisional application of Carrier was filed before the ‘409 patent, Carrier could only qualify as prior art if it could claim the benefit of priority to the earlier-filed provisional application to establish an earlier effective filing date.
The PTAB sided with Align, holding, based on their previous ruling in Penumbra Inc. v. RapidPulse, Inc., that a reference need only meet certain “ministerial” formalities to claim the earlier provisional date, without needing to show that the provisional's written description actually supported any claim of the later patent.
In Penumbra Inc. v. RapidPulse, Inc., No. IPR2021-01466 (P.T.A.B. 2023), the PTAB had previously interpreted the post-AIA rules for establishing an effective filing date for prior art under the post-AIA 35 U.S.C. § 102(d). The PTAB looked specifically at the language in 35 U.S.C. § 102(d), regarding prior art, that said “if the patent or application for patent is entitled to claim a right of priority under section 119, 365(a), 365(b), 386(a), or 386(b). . . based upon 1 or more prior filed applications for patent,” then that application would be considered “to have been effectively filed. . . as of the filing date of the earliest such application that describes the subject matter.”1 The PTAB contrasted that with how the law describes the effective filing date for a claimed invention, where it says that the effective filing date is “the filing date of the earliest application for which the patent or application is entitled.”2
Drawing a distinction between being entitled to claim a right of priority (35 U.S.C. § 102(d)) and actually being entitled to priority (35 U.S.C. § 100(i)(1)), the PTAB reasoned that U.S.C. § 102(d) only required that prior art only needs to satisfy “ministerial requirements” to gain the effective filing date of an earlier-filed provisional. The “ministerial requirements” include namely (1) making the priority claim while (2) the applications are co-pending and (3) have overlapping inventors.3
The Federal Circuit's Ruling
The Federal Circuit disagreed with the Board's “ministerial” standard. In reaching its decision, the Federal Circuit reviewed the text of 35 U.S.C. § 102(d), saying that “a patent or published application” is effectively filed for prior art purposes as of the earliest application “if the patent or application for patent is entitled to claim a right of priority under 35 U.S.C. [§] 119. . . .”4 Looking at 35 U.S.C. § 119, the Federal Circuit found it significant that it is specified that, for claiming priority to provisional applications, the law is explicit that a proper priority claim is “an application filed under section 111(a) or section 363 for an invention disclosed in the manner provided by section 112(a). . . in a provisional application.”5
Based on this, the Federal Circuit concluded that the test for the effective filing date of a prior art patent or published application is “expressly condition[ed]” on satisfaction of 35 U.S.C. § 112’s written description requirement.6 Furthermore, the Federal Circuit repudiated the PTAB’s interpretation, saying “there is nothing in its text that exempts prior art determinations from § 119(e)(1)’s entitlement requirements or otherwise creates a different, less demanding “ministerial” standard for prior art purposes.”7
Therefore, the Federal Circuit overruled Penumbra and established that, for prior art purposes, in order for a patent or patent application to receive the effective filing date of an earlier provisional application, the earlier provisional application must provide 35 U.S.C. § 112 written description support for the invention of the later application.8
Outcome
Because the Board never determined whether Carrier's provisional application actually provided written description support for any claim of the Carrier patent, the Federal Circuit vacated the Board's unpatentability decision and remanded the case. On remand, Align must show that the Carrier provisional supports at least one claim of the Carrier patent before Carrier can be used as prior art dated to that earlier filing.
Conclusion
Going forward, it is now clear that a prior art reference must actually find 112(a) written description support in its provisional application, in order to be given the effective filing date of that provisional application. For patent challengers, this means that, if you are relying on a provisional application’s filing date to establish a reference as prior art, you must examine the disclosure of that provisional application for written description support. For Patent Owners, this presents new opportunities to defeat prior art; when a piece of prior art needs a priority claim to an earlier-filed provisional application in order to be valid prior art, you should closely examine the provisional application for written description support.
1 35 U.S.C. § 102(d) (emphasis added).
2 35 U.S.C. § 100(i)(1).
3 Id.; 35 U.S.C. §§ 119, 120.
4 Id. at p. 9 (quoting 35 U.S.C. § 102(d)).
5 Id.; 35 U.S.C. §119(e)(1) (emphasis added).
6 Id. at p. 6.
7 Id.
8 Id. at p. 8-9.
