The Federal Circuit issued a precedential decision on August 10, 2026, in *Dental Monitoring SAS v. Align Technology, Inc.*, fundamentally reshaping how prior-art effective dates are determined.
The ruling directly targets the Patent Trial and Appeal Board’s so-called “ministerial” test, which had previously governed whether a patent qualifies for an earlier prior-art filing date.
Under the America Invents Act, a U.S. patent or published application can serve as a prior-art reference as of the date it was “effectively filed,” which may reach back to an earlier provisional application.
The PTAB had previously established its ministerial framework through its precedential ruling in *RapidPulse, Inc. v. Penumbra, Inc.*, setting a relatively low bar for claiming earlier priority dates.
Under the Penumbra rule, a reference patent only needed to satisfy ministerial requirements — such as filing a timely benefit claim — and show that the earlier application described the specific subject matter relied upon as prior art.
Critically, the Penumbra standard did not require the earlier provisional application to provide written-description support under 35 U.S.C. § 112(a) for any claim of the reference patent.
The case before the Federal Circuit arose from an inter partes review petition filed by Align Technology, challenging claims 1 through 15 of U.S. Patent No. 10,755,409.
The Board had determined that a reference known as Carrier, filed on November 18, 2020 and claiming priority to a provisional application filed on November 4, 2016, qualified as prior art based on the earlier provisional date.
The Federal Circuit rejected that framework, holding that the phrase “entitled to claim a right of priority to” in § 102(d)(2) imports the substantive requirements of § 119(e)(1), which conditions priority on compliance with § 112(a)’s written-description requirement.
The court reasoned plainly that “entitled to” cannot be reduced to merely asserting priority or meeting administrative formalities, marking a clear departure from the PTAB’s prior position.
The decision also addressed the Federal Circuit’s earlier Rule 36 affirmance of the Penumbra judgment, clarifying that such an order does not endorse any specific part of the Board’s reasoning and carries no precedential value.
In *Dental Monitoring*, the Federal Circuit squarely rejected the legal rule set out in the Board’s precedential Penumbra decision, rendering that standard no longer valid.
In its place, the court established a cumulative two-part framework for determining whether a reference patent may claim an earlier prior-art effective date based on a provisional application.
The first part requires that the earlier provisional application provide written-description support under § 112(a) for at least one claim of the reference patent or published application.
The second part requires that the earlier provisional application also describe the specific subject matter from the reference that is actually relied upon as prior art.
Both conditions must be satisfied, making the new framework meaningfully more demanding than the ministerial test it replaces.
Because the record did not establish whether Carrier’s provisional application provided the necessary written-description support, the Federal Circuit vacated the Board’s decision and remanded the case for further consideration.
The court determined that remand was the more appropriate route rather than outright reversal, giving the Board an opportunity to apply the new framework to the existing record.
For patent practitioners, the ruling signals that parties relying on earlier priority dates to establish prior art must now ensure provisional applications robustly support at least one claim of the reference, not merely describe relevant subject matter.
The decision is expected to have wide-reaching implications for inter partes review proceedings, particularly in cases where the prior-art date of a reference depends on an earlier provisional filing.