IP Law Daily, PATENT—Fed. Cir.: Priority for prior art requires written description support in provisional application, (Aug 12, 2026)

By Steven D. Cole, J.D.

The Patent and Trial Appeal Board incorrectly held that a provisional patent application was sufficient to claim a right of priority based on reasoning that contravened the clear text of the America Invents Act.

The appellant in this proceeding arising from a decision of the U.S. Patent and Trial Appeal Board (Board) successfully showed that the Board had applied the wrong legal analysis, according to the Federal Circuit Court of Appeals. The dispute involved a prior art reference, and centered on whether a certain patent application was entitled to the earlier filing date of its provisional application or whether it should be considered “effectively filed” at the later date of its non-provisional application. The court interpreted the relevant statutory text to mean that a prior art reference will be credited with an earlier provisional filing date only if the provisional application satisfies the written description requirement set forth in section 112(a) of the Leahy-Smith America Invents Act (AIA) (Dental Monitoring SAS v. Align Technology, Inc., No. 25-1752 (Fed. Cir. Aug. 10, 2026)).

Background. Dental Monitoring SAS (Dental Monitoring) is a global intelligent platform dedicated to providing “connected, smarter and more sustainable dental care,” according to its website. It owns U.S. Patent 10,755,409 (’409 patent), which is directed to a method for acquiring and analyzing an image of a patient’s dental arch. Align Technology (Align), a medical device company, filed a petition for an inter partes review at the U.S. Patent and Trademark Office, challenging claims 1–15 of the ’409 patent. The Board determined that the challenged claims were unpatentable as obvious over the combination of three prior art references, including U.S. Patent Application Publication 2021/0068923 A1 (Carrier). Importantly, the Board found that the effective filing date of the ’409 patent, based on a foreign priority application, fell between the filing dates of Carrier’s provisional application and its non-provisional application. Accordingly, whether Carrier qualified as prior art depended on whether it was entitled to the earlier filing date of its provisional application under 35 U.S.C § 102(d)(2). The Board concluded that it was, and Dental Monitoring timely appealed this decision.

Issue. The central issue before the Federal Circuit Court of Appeals was whether Carrier was considered “prior art” under the AIA. Specifically, the parties disputed whether Carrier’s provisional application needed to provide written description support for one of its published claims in order for Carrier to obtain the benefit of its provisional date (and thus predate the ’409 patent), or whether Carrier only needed to comply with certain “ministerial” requirements of claiming priority.

Statutory framework. The AIA provides that a patent or published patent application may qualify as prior art as of the date it was “effectively filed.” 35 U.S.C § 102(a)(2). The law specifies that the patent or application will be considered to have been effectively filed “if the patent or application for patent is entitled to claim a right of priority under section 119 … or to claim the benefit of an earlier filing date under section 120 … based upon 1 or more prior filed applications for patent, as of the filing date of the earliest such application that describes the subject matter.” Id. § 102(d)(2). Section 119, in turn, requires that the application be “disclosed in the manner provided by section 112(a).” Id. § 119(e)(1). Section 112(a) unequivocally states that the specification “shall contain a written description.” Id. § 112(a).

Analysis of the court. The statutory text expressly conditions entitlement to priority on satisfaction of AIA section 112(a)’s written description requirement. Thus, the Board erred when it found that, for purposes of section 102(d)(2), a reference patent receives the filing date of an earlier application so long as it satisfies the “ministerial requirements” of sections 119 and 120, and if the earlier application describes the subject matter relied upon in the reference patent. The court emphasized that nothing in the AIA’s text “exempts prior art determinations from § 119(e)(1)’s entitlement requirements or otherwise creates a different, less demanding ‘ministerial’ standard for prior art purposes.” The court stressed that the Board’s interpretation would effectively treat section 102(d)(2) as though it referred simply to a patent that “claims” or “asserts” a right of priority loosely in general terms.

Align argued in support of the Board’s interpretation by appealing to legislative history. Specifically, it pointed to floor statements indicating that section 102(d) required only “ministerial” priority requirements, rather than written description support. The court found this line of reasoning unpersuasive because the statutory text was clear and unambiguous.

Align also argued that the AIA’s distinction between a claimed invention’s effective filing date under section 100(i) and a reference’s effective filing date under section 102(d) eliminated any requirement that the earlier application provide section 112 support for the subject matter relied upon as prior art. However, as the court explained, this distinction is intended to identify which statutory inquiry is being performed; it does not determine what substantive requirements the term “entitled” incorporates: “[N]othing in § 100(i) suggests that Congress intended § 102(d) to dispense with those substantive requirements when determining a reference’s effective filing date for prior art purposes.”

Therefore, the court vacated the Board’s decision and remanded the case in order for the Board to make factual findings with regard to whether Carrier’s provisional application provided sufficient written description support, per section 112(a).

The Case is No. 25-1752.

Judge: Lourie, A.

Attorneys: Michael P. Sandonato (Venable LLP) for Dental Monitoring SAS. Hari Santhanam (Ashurst Perkins Coie U.S. LLP) for Align Technology, Inc.

Companies: Dental Monitoring SAS; Align Technology, Inc.

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