US 11826445

I'll verify against live sources before summarizing.

US 11,826,445 B2 — Verification Summary

Sources used: Google Patents (mirrors USPTO bibliographic/grant data), Patexia, Stanford NPE Litigation Database, and a Delaware district-court complaint excerpt. I did not have direct API access to USPTO PatentCenter or the CAFC docket; findings below are from those mirrored/secondary sources. Uncertainty flags are noted.

Bibliographic data

Chain of priority (as recited in the patent): 18/049,843 ← 17/659,473 (US 11,826,444) ← 17/557,560 ← 16/784,582 (US 11,219,582) ← 15/627,906 (US 10,646,419) ← 14/710,416 (US 9,789,036) ← 12/329,582 (US 9,295,619), a CIP of 11/307,463 filed Feb. 8, 2006.

⚠️ Note on term: because the patent claims 2006 priority, its 20-year term ran from Feb. 8, 2006 and the listed expiration is Feb. 8, 2026. As of today (April 26, 2026), the patent has expired. I could not verify from the sources retrieved whether any PTA or terminal disclaimer altered this. The family history shows a terminal disclaimer was noted on sibling US 10,646,419.

Abstract (as printed)

"The present invention is a formable dental treatment tray utilizing poly(2-ethyl-2-oxazoline) and a gelatinous active. Blending of the active is accomplished by mixing the Poly(2-ethyl-2-oxazoline) with an active ingredient, such as a peroxide like hydrogen peroxide, carbamide peroxide, sodium perborate, or sodium percarbonate, usually also with water or an appropriate organic solvent. Peroxide concentrations in these new gels can reach a 30% concentration of hydrogen peroxide while maintaining a shelf life of six months at room temperature without developing peroxide decomposition. The gels are applied to an appropriate backing and dried to a gelatinous state. In use, the active is hydrated and regains adhesiveness. Then the tray is pressed and formed around a user's dental arch to form the customizable tray. Multiple active ingredients may be used, with or without peroxide, for accomplishing desired treatment regimens."

Independent claims — plain language

This patent has only two claims, both independent, and both are drafted as device claims ("A dental bleaching device, comprising…"). There is no method claim and no dependent claim.

Claim 1 — the "conformable device" claim

• A strip of backing material that is flexible and planar, i.e., it has two flat sides.
• A gelatinous, non-coalescent, visco-elastic dental composition joined to at least part of one flat side.
  • "Non-coalescent" ties to the specification's definition: discrete pieces of the material won't merge into one body.
• The composition contains three things: (a) a peroxide bleaching agent, (b) a solvent, and (c) a thickening agent selected from the closed set consisting of polyethyloxazoline and polyvinylpyrrolidone (PVP).
  • This is a closed Markush group ("consisting of") — on its face it excludes other thickeners such as CARBOPOL, silica, or PEG.
• Functional limitation: when adhered to a user's dental arch, both the composition and the backing flex and conform to the arch without cracking or breaking.

Claim 2 — the "shelf-stable device" claim

• Same basic structure: flexible, planar backing strip with two flat sides; a non-fluid dental composition joined to at least part of one flat side.
• Same three-part chemistry: peroxide bleaching agent + solvent + thickener from the same closed set (polyethyloxazoline / PVP).
• Adds a dual-state stability requirement: the joined composition must remain gelatinous, non-coalescent, and visco-elastic (i) during storage at room temperature for up to six months in a package, and (ii) after removal from the package and adhesion to the dental arch — such that the composition and backing together flex and conform to the particular irregularities of the user's dental arch without cracking or breaking.

Practical difference between the two: Claim 1 focuses on physical form (gelatinous/non-coalescent/visco-elastic) plus conformability. Claim 2 layers on the package-storage durability timeline (six months at room temperature) and explicitly recites conforming to individual arch irregularities, and additionally requires the composition to be "non-fluid."

Terminology note (flagged, not corrected): the specification repeatedly calls the thickener poly(2-ethyl-2-oxazoline), while the claims recite "polyethyloxazoline." The patent does not expressly equate these terms in the text I have; that potential claim-construction gap is the kind of issue that would matter in litigation. The specification also states PVP "may be used in this invention with good results," though "not as preferred."

Litigation posture (district courts; no CAFC appeal found)

The Google Patents page lists multiple suits involving this patent, and the Stanford NPE Litigation Database lists two asserting cases:

1. CAO Group, Inc. v. GuruNanda, LLC, No. 8:25-cv-02074 (C.D. Cal., filed Sept. 12, 2025).
2. CAO Group, Inc. v. The Individuals…Identified on Schedule A, No. 1:24-cv-01211 (N.D. Ill., filed Feb. 12, 2024) — a large "Schedule A" e-commerce defendant action.

Additional cases listed on Google Patents for this patent:

• 2:24-cv-00175 and 2:24-cv-00498 (D. Utah)
• 1:24-cv-04903 (N.D. Ill.) — CAO Group v. Karaka LLC d/b/a The DoubleY Brands; voluntarily dismissed Dec. 18, 2024 per Patexia.
• 1:24-cv-05129 (N.D. Ill.)
• 8:25-cv-02074 (C.D. Cal.)
• 1:25-cv-01430 (D. Del.) — CAO Group, Inc. v. Ivoclar Vivadent, Inc. A complaint excerpt confirms US 11,826,445 is one of the five patents-in-suit (along with 10,602,259; 10,646,419; 11,219,582; and 11,826,444).

On your specific request re: CAFC 2026 dockets — I found no Federal Circuit appeal in 2026 involving US 11,826,445, and no CAFC docket number for it. My searches returned unrelated 2026 Federal Circuit matters (e.g., Sanofi/Ablynx, Netflix v. DivX, Woodway/LifeCORE). I cannot rule out a pending appeal that isn't indexed in the sources I reached, so treat "no CAFC appeal" as not found rather than definitively nonexistent.

Confidence and caveats

• High confidence: title, patent/application numbers, filing and issue dates, inventors, assignee, abstract text, and the content of the two claims (taken directly from the authoritative full text supplied).
• Moderate confidence: expiration date and "Expired – Lifetime" status — these are Google Patents legal-status assumptions, which the page itself disclaims as not a legal conclusion. Given the 2006 priority date, a Feb. 2026 expiration is arithmetically consistent.
• Lower confidence: completeness of the litigation list. PACER/docket-level verification was not performed, so pending motions, transfers, or newer filings may exist that these sources don't reflect.
• If you need prosecution-history detail (office actions, prior-art rejections, terminal disclaimers), that requires the USPTO PatentCenter file wrapper, which I could not query directly here.

I'll research litigation involving US Patent 11826445. Let me search multiple sources.

I have substantial results. Let me verify specific case details and check for additional cases.

Known Litigation Involving U.S. Patent No. 11,826,445

Important scope notes before the list:

• U.S. Patent 11,826,445 B2 ("Peroxide gel compositions," issued Nov 28, 2023) is a continuation of a large family. It was asserted alongside its sibling patents — U.S. 10,603,259; 10,646,419; 11,219,582; and 11,826,444 — in nearly every action. When a source lists the family generally, I have flagged below where I could specifically confirm the '445 was named.
• The '445 has a priority date of 2006-02-08 and a filing date of 2022-10-26; per Google Patents it is presently marked "Expired – Lifetime," with adjusted expiration 2026-02-08. That expiry affects the practical value of ongoing claims but does not itself terminate pending cases.
• Sources conflict on completeness. Google Patents' own page for the '445 lists six litigation matters ("Family has litigation"). The Stanford NPE Litigation Database lists only two. I have combined these and cross-checked against docket aggregators and complaint filings.

Confirmed matters naming the '445 patent

Key details per matter

1. CAO Group v. Walmart (D. Utah 2:24-cv-00175). Asserted '259, '419, '582, '444, and '445. CAO's counsel: Lahti Helfgott, LLC. Walmart's counsel: Greenberg Traurig LLP and Warner Norcross & Judd LLP. The parties stipulated to dismissal with prejudice, each side waiving costs and fees — a negotiated exit rather than a merits ruling. Walmart (Equate whitening strips) is a Ranir customer, which led directly to Ranir's DJ suit below.

2. Ranir LLC v. CAO Group (D. Utah 2:24-cv-00498). Offensive declaratory-judgment action by Ranir (a Michigan LLC; Rembrandt-brand and private-label whitening strips) seeking declarations that its products do not infringe, and that the asserted patents are invalid, based on Ranir's claimed pre-2002 prior art (an "OCL" three-polymer/hydrogen-peroxide formulation). The complaint recounts CAO's cease-and-desist campaign against Ranir's customers (Walmart, CVS, Kroger, Meijer, Walgreens, Target, Albertsons). Status: pending as of the latest available docket information.

3. CAO Group v. Karaka (N.D. Ill. 1:24-cv-04903). Accused product: "Boka Bright + White Sensitive Smile Whitening Strips." Voluntarily dismissed (Dec 18, 2024).

4. CAO Group v. GD-Whitening (N.D. Ill. 1:24-cv-05129). Originally part of the Schedule A case 1:24-cv-01211; severed on the court's finding of improper joinder under 35 U.S.C. § 299. The court found willful infringement and entered a default judgment: reasonable royalty ($500,000) + hypothetical licensing costs ($50,000), trebled to $1,650,000; also ordered third-party payment processors (Amazon Pay, eBay, PayPal, Payoneer, Walmart) to release restrained funds. Because it was a default, there is no merits ruling on validity or infringement.

5. CAO Group v. Schedule A Defendants (N.D. Ill. 1:24-cv-01211). A mass-joinder action against dozens of online seller aliases (e.g., Fairywill, BYS Technology, OETU, Trayknick). This is the case the Stanford NPE Litigation Database identifies as involving the '445.

6. CAO Group v. GuruNanda (C.D. Cal. 8:25-cv-02074). Defendant/accused product: GuruNanda (whitening strips/oil pulling brand). Pending.

7. CAO Group v. Ivoclar Vivadent (D. Del. 1:25-cv-01430). Accused product: VivaStyle Teeth Whitening Strips (product label lists PVP K30/K90, distilled water, and 6% hydrogen peroxide). Pending.

Caveats and uncertainty

• Filing dates. The Walmart filing date (~Mar 5, 2024) is drawn from the Ranir complaint's narrative rather than a docket header; treat as approximate pending PACER confirmation.
• Which cases actually name the '445. I could specifically confirm the '445 in the Walmart, Ranir, Karaka, GD-Whitening, and Ivoclar pleadings, and it is listed for the 1:24-cv-01211 Schedule A case and GuruNanda matter. CAO filed numerous other Schedule A cases that assert the same patent family (e.g., 1:24-cv-00901; 1:25-cv-04054; 1:25-cv-08205; 1:25-cv-12503; 1:25-cv-14512). I cannot confirm that the '445 specifically (as opposed to its siblings '259/'419/'582/'444) was asserted in each of those; some may assert only the other family members. Do not treat this list as exhaustive of CAO's family-wide enforcement campaign.
• Stanford NPE database and Google Patents disagree on the count (2 vs. 6). Google's "Family has litigation" tab lists the six matters identified above; the Stanford database (last updated before the later CAO suits) shows only GuruNanda and the 1:24-cv-01211 Schedule A case.
• No appellate (CAFC) activity was identified for the '445. No PTAB/IPR proceedings against the '445 were found in these searches.
• Given the '445's expiration (2026-02-08), and today's date of April 26, 2026, the patent term has lapsed, which will likely moot prospective injunctive relief, though past-damages claims in the pending matters may survive.

If you need docket-level certainty, the authoritative sources are PACER (for D. Utah, N.D. Ill., C.D. Cal., and D. Del.) and the CourtListener RECAP archive; the Stanford NPE database and Unified Patents portal are useful but demonstrably incomplete here.

Proceedings overview

Total AIA trial proceedings on file for US 11,826,445: 0. Per the structured USPTO Open Data Portal block in this prompt ("no AIA trial proceedings … as of the most recent ingest"), and consistent with my own targeted searching — no IPRs, no PGRs, and no CBMs — the breakdown by status is: 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denied. The bottom line for a defendant is therefore not "claims 1–2 are dead," but rather the inverse: both claims of this patent are entirely untested at the Board and remain presumptively valid — however, the patent itself expired on 2026-02-08, which materially blunts what an assertion can win. Your defensive posture should be built on district-court invalidity, non-infringement, and the expiration/§ 286 damages cutoff, not on an IPR record, because there isn't one.

No proceeding-specific sections follow, because there are no proceedings to describe. What follows is the context a defendant actually needs.

Why the absence is real, not a data gap

• The patent is expired. Google Patents records an "Adjusted expiration" of 2026-02-08 and a legal status of Expired – Lifetime, derived from the 2006-02-08 priority date (the '445 issued 2023-11-28 from App. No. 18/049,843, filed 2022-10-26, as a continuation in a chain reaching back to App. No. 11/307,463 filed 2006-02-08). As of today, 2026-09-28, the patent has been expired for roughly seven months.
• The PGR window has long closed. The '445 issued 2023-11-28; the 9-month § 321(c) PGR window closed on or about 2024-08-28. No PGR exists on file. CBM is unavailable — the transitional CBM program sunset for new petitions on 2020-09-16, and these dental-device claims would not qualify as a "covered business method" in any event.
• The IPR window was never used by anyone. Neither Ranir/Perrigo nor any Schedule A defendant nor Unified Patents appears to have petitioned. I could not exhaustively query PTAB E2E/CourtListener on every family member, so treat this as "no indication of PTAB activity found," not a certified negative. The canonical ODP block controls.

The litigation that surrounds this patent (the "why no IPR" answer)

The patent has been heavily asserted in district court — which makes the absence of any IPR petition a notable signal rather than a default:

• Ranir LLC v. CAO Group, Inc., No. 2:24-cv-00498-RJS (D. Utah, filed 2024-07-16) — a declaratory judgment action of non-infringement and invalidity against the '259, '419, '582, '444 and '445 patents. Ranir (a Perrigo subsidiary) pleaded that its oral care layer ("OCL") has been the same since 2002 and that its 2002-era application (U.S. Appl. No. 10/187,666, pub. US 2004/0005277) predates the asserted family. Source: D. Utah complaint, archive.org.
• CAO Group, Inc. v. Walmart, Inc., No. 2:24-cv-00175 (D. Utah) — CAO asserted Claim 1 of each of the five patents, including the '445; dismissed with prejudice by stipulation, each side bearing its own fees.
• CAO Group v. Ivoclar Vivadent, Inc., No. 1:25-cv-01430 (D. Del., filed 2025) — the '445 is asserted against VivaStyle Teeth Whitening Strips (hydrogen peroxide + PVP K30/K90 on a flexible strip).
• CAO Group Schedule A cases — e.g., N.D. Ill. Nos. 1:24-cv-01211, 1:24-cv-04903, 1:24-cv-05129; C.D. Cal. No. 8:25-cv-02074. In the N.D. Ill. Schedule A action, defendants argued (and the court credited for purposes of dissolving a preliminary injunction/asset freeze) that the accused strips practice U.S. Pat. Nos. 5,891,453 and 5,894,017 — the P&G Sagel strip patents — and lack a drying step. See N.D. Ill. Dkt. 102, CourtListener.

Pattern signal: CAO Group is itself a sophisticated PTAB litigant as petitioner — it filed IPR2014-00796, -00797 and -01798 against P&G's whitening-strip patents (all denied institution; Jones Day case note) and challenged the '199 and '569 patents. Ranir is likewise a repeat player — it petitioned for IPR2017-01878 against P&G's '017 patent, which was instituted (institution decision) and later settled. So both sides of this fight know how to file an IPR — the empty docket reflects a strategic choice (probably the July 2024 § 315(b) one-year window in the Utah DJ case, plus the futility of invalidating a patent that expires in February 2026), not ignorance.

Strategic summary

Claim status on the '445: both claims are UNTESTED. The patent has exactly two claims, both independent (1 and 2), as CAO pleaded in its own complaints ("characterized by its two independent claims"). Claim 1 covers a dental bleaching device with a flexible planar backing strip bearing a gelatinous, non-coalescent, visco-elastic dental composition comprising a peroxide bleaching agent, a solvent, and a thickening agent selected from polyethyloxazoline or PVP, flexing and conforming to the dental arch without cracking or breaking. Claim 2 is narrower in one respect and broader in another: it recites a non-fluid dental composition and adds the storage-stability limitation — gelatinous/non-coalescent/visco-elastic during storage at room temperature for up to six months in a package and after removal and adhesion to the arch. Because no IPR was ever instituted, there is no FWD, no cancellation, and no narrowing amendment to cite. If a demand letter leans on Claim 1, you cannot point to a PTAB record killing it; you must attack it on the merits.

Estoppel landscape: § 315(e)(2) estoppel is empty, and your prior-art runway is wide open. No petitioner has ever been estopped as to this patent, because no IPR reached FWD. That means every ground — § 102 anticipation, § 103 obviousness, § 112 written description/enablement/indefiniteness — is available to you in district court. The most promising art is the art the family never had to face: the P&G Sagel strip patents (U.S. 5,891,453; 5,894,017; 5,989,569; 6,045,811; 7,122,199), Ranir's own 2002-era OCL application (US 2004/0005277), and U.S. Pub. 2004/0241110 to Lee ("Jelly-type tooth-bleaching patch") — the only reference cited by the examiner during prosecution of the family. Critically, the '445 is a 2006-priority continuation whose claims issued in 2023, so intervening-art and § 112 written-description attacks aimed at the 2006 specification's support for "non-fluid … up to six months" language deserve close attention.

Do not expect the Board to bail you out now. Three obstacles: (1) the patent expired 2026-02-08, so an IPR today could only serve a past-damages purpose and would be expensive relative to value; (2) under current USPTO policy, the Director decides institution (Oct. 16, 2025 Squires memorandum), institution rates have collapsed (roughly 25.9% under Squires per Law360/Mayer Brown), and the proposed rules would bar IPR outright where a patent already survived a validity challenge; and (3) the "settled expectations" doctrine — applied to deny institution against old patents — cuts hard against a 20-year-old priority family like this one (Smith Law overview). A discretionary denial is the most likely outcome of any petition you file.

Recommended next steps

1. Confirm the negative yourself before relying on it. Run a party and patent-number search on PTAB E2E (https://ptacts.uspto.gov/ptacts/) for "11,826,445," "18/049,843," "Cao Group," "Ranir," "Perrigo," and "Unified Patents." The ODP block is authoritative for what's been ingested, but a newly filed petition may not have surfaced yet.
2. Lead with expiration + § 286. The '445 expired 2026-02-08. There is no prospective injunctive relief and no ongoing royalty. Damages are capped by the six-year lookback from the date your complaint was served. Quantify the actual exposure window before spending six figures on invalidity.
3. Attack Claim 1 and Claim 2 separately in district court. Claim 1's "gelatinous, non-coalescent, visco-elastic" and "without cracking or breaking" limitations are functional and invite § 112 indefiniteness and enablement attacks; Claim 2's "six months in a package" limitation is a testable, falsifiable proposition you can defeat with accelerated-stability evidence on the accused product.
4. Mirror the winning Schedule A arguments. The N.D. Ill. record (Dkt. 102) shows the "no drying step" non-infringement theory landing against the '444's "[d]ried to an extent that it no longer remains in a state of fluidity" limitation. The '445's Claim 2 "non-fluid" limitation is close kin — if your product is manufactured in a viscous, never-dried state, that is a clean non-infringement story.
5. Coordinate with the Ranir/Perrigo DJ if you are a co-accused or a customer. Ranir's invalidity contentions in 2:24-cv-00498-RJS, and the prior-art proofs it tendered in July 2023, are the deepest existing invalidity work product on this family. A defense-side or indemnity alignment there is worth far more than a fresh petition.
6. If you do file an IPR, file before you are served. § 315(b) gives you one year from service of a complaint alleging infringement of the '445. Every Schedule A and Iveclar complaint in this campaign was built to make that clock run out.

Caveat: I found no PTAB proceeding, FWD, or Federal Circuit appeal touching US 11,826,445. I have not fabricated a proceeding number, panel, or disposition. Where I could not verify a fact to a primary source — notably the absence of petitions against the sibling patents '259/'419/'582/'444 — I have said so rather than assert it.

I'll research the ownership and litigation record before assembling the report.

Let me dig into the assignment records and Cao Group's corporate status.

Let me check for additional assignments, litigation details, and PTAB challenges.

Ownership & Assignment Analysis — US 11,826,445 B2 ("Peroxide gel compositions")

Verification starting point: USPTO Assignment Center → https://assignmentcenter.uspto.gov/ (search by patent number 11826445); mirrored at https://assignment.uspto.gov/patent/index.html. Google Patents legal-events record: https://patents.google.com/patent/US11826445/en

Bottom line up front: This is a single-link chain. There is no assignment from the operating company to any third party. The only recorded assignment is a confirmatory inventors → original assignee instrument — executed in 2015 but not recorded until 2023. The patent is now expired (adjusted expiration 2026-02-08), so the enforcement window has closed.

Inventors

Unusual patterns check: The classic red flag (all inventors leaving the original assignee within 12 months of filing) is absent — the opposite is true. Both inventors remained associated with CAO through at least the 2024 filings. The genuinely unusual item is in the recording behavior, not the personnel: the inventors' assignment was executed 2015-05-28/29 but not recorded until 2023-09-11, an ~8-year recordation lag that coincides with the run-up to the 2024 assertion campaign (see timeline below).

Original assignee

CAO Group, Inc. — a Utah corporation, 4628 West Skyhawk Drive, West Jordan, UT 84084 (per its own complaints; earlier assignments list 8683 South 700 West, Sandy, UT 84070).

• Primary line of business: Operating dental/medical device manufacturer. Headquartered in a 60,000 sq ft FDA-registered, ISO 13485/9001-certified facility; ~51–200 employees; 160+ patents claimed. Product lines include dental diode lasers (later consolidated under the AMD Lasers sub-brand), LED curing lights, and the asserted product line, "Sheer White!" teeth whitening strips, sold via caogroup.com and authorized distributor Henry Schein.
• Did they ship a product embodying the claims? Yes. CAO's complaints expressly allege it "developed a product line which embodies Plaintiff's Patents, under the name 'Sheer White! Teeth Whitening Strips'" and that notice of patent rights appears on the packaging. This is a product-practicing patentee, not a paper owner.
• Current status: Operating — no bankruptcy, dissolution, or acquisition surfaced. Note: CAO's earlier 2011–2015 history includes being sued by Procter & Gamble and filing IPRs against P&G's strip patents (IPR2014-00797 on US 6,045,811; a parallel petition on US 5,989,569), i.e., CAO has been on both sides of this exact technology space for over a decade.

Assignment timeline

For US 11,826,445 specifically, the Assignment Center record resolves to one recorded assignment:

• 2015-05-28 / 2015-05-29 (executed, per the two inventors' signing dates) / recorded 2023-09-11 — Reel 064860/0918
  • Conveyance: Assignment of assignors' interest (recorded event code AS; brief text: "ASSIGNMENT OF ASSIGNORS' INTEREST;ASSIGNORS:JENSEN, STEVEN D;CAO, DENSEN;SIGNING DATES FROM 20150528 TO 20150529")
  • Assignor: Steven D. Jensen and Densen Cao
  • Assignee: CAO GROUP, INC. (Utah)
  • Correspondent: Not published in the record surfaced to me. I could not retrieve the correspondent-of-record field for reel 064860/0918, so I will not guess at it. For context only — and not part of this chain — CAO's earlier 2004–2006 SLC recordings (e.g., reel 17962/0419, executed 2006-05-28, recorded 2006-06-08, Cao → Cao Group) were handled by Daniel P. McCarthy, Parsons Behle & Latimer, 201 South Main St., Suite 1800, Salt Lake City, UT. Do not treat that as the correspondent for reel 064860/0918 without independent verification.
  • Context: Chain-of-title perfection / confirmatory assignment to the same original assignee — not an acquisition, not a sale. Recorded 5.8 months before the first infringement suit (2024-03-05), consistent with a standing clean-up before enforcement.

No other post-issuance assignments were found — no shell-entity transfer, no security agreement, no merger, no change of name, no release, and no transfer to any NPE or defensive aggregator. The sister patent US 11,826,444 B2 (from application 17/659,473, filed 2022-04-15, issued the same day 2023-11-28) sits in the same family and is asserted alongside the '445; the family table shows the same single-owner structure.

Litigation context (for the standing analysis, not assignments):

Plaintiff counsel throughout is CAO's own outside firm, Lahti Helfgott, LLC (Brian E. Lahti, Jonathan A. Helfgott) — not a contingency-driven NPE assertion shop.

Timeline diagram

timeline
    title Ownership of US 11826445
    2006 : Priority application filed Feb 8
    2008 : Continuation in part filed Dec 12
    2015 : Inventors assign rights to Cao Group
    2022 : Continuation filed Oct 26
    2023 : Assignment recorded Sep 11
         : Patent issued Nov 28
    2024 : First suits filed against Walmart and others
    2026 : Patent term expires Feb 8

NPE / troll-pattern signals

1. Shell-entity transfer — not present.
No assignment to any "IP / Patents / Licensing / Holdings / Ventures" entity. The only recorded instrument (reel 064860/0918) runs toward the operating company, not away from it. Current assignee per Google Patents remains Cao Group, Inc. No single-purpose Delaware/Texas LLC appears anywhere in the chain.

2. Known asserter in the chain — not present.
Neither current nor prior assignee matches any listed NPE (Acacia, Marathon, IV, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg entities). CAO Group is a manufacturer with published addresses, product catalogs, an FDA-registered facility, and named executive leadership. It is a serial plaintiff, but serial plaintiff ≠ NPE.

3. Repeat correspondent across the chain — not present (with a data caveat).
With only one recorded link, there is no recurrence to detect. The correspondent field for reel 064860/0918 was not retrievable in the source I could access; this is the one field the Assignment Center would settle definitively and I am flagging it rather than inferring it. (CAO's 2006-era recordings used Daniel P. McCarthy / Parsons Behle & Latimer, reel 17962/0419 — different patent, offered only as firm context.)

4. Cascading transfers — not present.
Zero chained LLC transfers. One link, one assignee, no shared correspondent addresses, no common-principal issues.

5. Pre-litigation transfer — present, but qualified and non-supportive.
The recording of reel 064860/0918 on 2023-09-11 falls within 6 months of the first suit's filing on 2024-03-05. However, the assignment was executed 2015-05-28/29 and moved the patent from the inventors to the same company that already owned it — there was no change of beneficial owner, no venue-shifting transfer, and no transfer to an assertion vehicle. This is a standing/chain-of-title perfection recording, a standard pre-enforcement housekeeping step. It satisfies the letter of the timing test but carries none of the NPE inference the test is designed to capture. I would not count it toward an NPE finding.

6. Bankruptcy fire-sale — not present.
No Chapter 7/11 evidence. The 2022-10-26 filing, 2023-11-28 grant, and 2024–2025 assertion campaign are inconsistent with a distressed asset sale. (Contrast Kodak/Nortel/Polaroid-type chains — nothing analogous here.)

7. Privateering — not present.
No NPE asserts on CAO's behalf. CAO asserts in its own name, through its own retained counsel, against parties selling competing whitening strips (Walmart's Equate private label, Karaka/DoubleY, Schedule A e-commerce sellers). This is direct, self-interested brand enforcement.

8. Defensive aggregator (anti-NPE) — not present.
The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. Inverse signal is therefore also not triggered; the patent was never neutralized by aggregation.

Verdict

Operating-company assertion.

CAO Group, Inc. is the sole owner per the only recorded assignment in the chain — reel 064860/0918, executed 2015-05-28/29 and recorded 2023-09-11, an inventors-to-company confirmatory instrument with no subsequent transfer to any third party. CAO is a product-practicing Utah manufacturer that sells the asserted "Sheer White!" whitening strips (via caogroup.com and Henry Schein) and asserts the '445 itself against commercial competitors and e-commerce sellers, rather than licensing it out. The 2023-09-11 recording does fall inside the 6-month pre-suit window, but because the beneficiary is the same entity, it is chain-of-title perfection rather than a pre-litigation transfer, and no other NPE signal is present.

Verification: search patent number 11826445 at https://assignmentcenter.uspto.gov/ (or https://assignment.uspto.gov/patent/index.html) to confirm reel 064860/0918 and to retrieve the correspondent-of-record field I could not access here.

Data limitations I will not paper over

• Correspondent of record for reel 064860/0918: unknown to me. I could not retrieve it, and I declined to substitute CAO's historical 2006 correspondent for it.
• Total assignment count may be 1 or more. Google Patents' legal-events feed for this patent lists only the 2023-09-11 entry, but that feed is not exhaustive for license or security-interest recordings. A direct Assignment Center query is the only way to be certain.
• I did not fabricate the intervening chain. The '444 sibling patent and the abandoned applications (17/557,560; 18/348,960; 18/459,268) are separate property; I did not invent assignment records for them.
• Post-2020 corporate events (bankruptcy, acquisition) would not necessarily appear on the patent face; I found no evidence of either, but absence of evidence in a patent-record search is not proof of absence.

I'll research this systematically. Let me start with searches on the patent and its cited references.

Let me verify the citation record on the USPTO side and look into the litigation/IPR activity, plus the key family-cited references.

Identification confirmed

Searching for the literal identifier 11826445 returns a single hit: US 11,826,445 B2 — "Peroxide gel compositions" (Cao Group, Inc.; inventors Steven D. Jensen and Densen Cao; application US 18/049,843 filed 2022‑10‑26; granted 2023‑11‑28; earliest priority 2006‑02‑08; Google's status line reads "Expired – Lifetime, expires 2026‑02‑08"). No other patent shares that number, and I have not substituted any similar number.

Sources: https://patents.google.com/patent/US11826445/en ; https://patents.justia.com/patent/11826445 ; https://patexia.com/us/patent/11826445

The claims being tested against the art (only two claims exist)

• Claim 1 — dental bleaching device: (a) flexible, planar strip of backing material with two flat sides; (b) a gelatinous, non‑coalescent, visco‑elastic dental composition conjoined to at least a portion of one flat side; (c) composition = peroxide bleaching agent + solvent + thickening agent selected from the set consisting of polyethyloxazoline and PVP; (d) when adhered to a dental arch, both the composition and the backing flex and conform without cracking or breaking.
• Claim 2 — same, with "non‑fluid" composition that remains gelatinous, non‑coalescent and visco‑elastic during storage at room temperature for up to six months in a package and after removal/adherence, conforming to the particular irregularities of the arch without cracking or breaking.

Two things drive the whole §102 analysis: (i) the closed Markush group "consisting of polyethyloxazoline and PVP" — poly(2‑ethyl‑2‑oxazoline) and polyvinylpyrrolidone are the only permitted thickeners; and (ii) the critical date is nominally 2006‑02‑08, though the chain runs through a continuation‑in‑part (US 12/329,582, filed 2008‑12‑06), so claim language arguably added in 2008 (e.g., "non‑coalescent," "flex… without cracking or breaking," the PVP alternative) may only be entitled to a 2008 date. That uncertainty is exactly what the co‑pending litigation exploits (Ranir DJ complaint, D. Utah 2:24‑cv‑00498).

1. The only patent citation of record on the '445 itself

Google Patents lists "Citations (1) / Patent Citations (1)" for US 11,826,445 B2 — a single examiner reference. (Contrast the parent US 9,789,036 B2, whose page shows "Patent Citations (27).")

Sources: https://patents.google.com/patent/US20040241110 ; https://patentimages.storage.googleapis.com/5d/a8/dd/4556e1574496c0/US20040241110A1.pdf

2. The family‑level citations ("Family Cites Families (28)")

These are the 28 references cited in the '445's patent family (they appear on siblings such as US 9,789,036 B2, whose page shows 27–28 citations). They are the substantive prior‑art universe for the same specification. Because only "polyethyloxazoline and PVP" are claimed thickeners, the references are §102 candidates only to the extent they put a PVP/polyethyloxazoline thickener together with a flexible backing strip, a peroxide and a solvent. I flag where I have not personally verified the thickener disclosure in the reference text.

3. Prior art surfaced by the litigation that is not on the '445 face

Because the '445 is being asserted (CAO Group v. Ranir customers; Ranir's DJ action, D. Utah 2:24‑cv‑00498, filed 2024‑07‑16), materially stronger §102/§103 art has been identified by the accused infringer but does not appear on the '445's citation list:

• Ranir's U.S. Appl. No. 10/187,666, published as US 2004/0005277 A1 (2004‑01‑08) — flat sheets shaped to form wraps with an oral care layer (OCL) that is a blend of three polymers activated with a hydrogen peroxide solution. Ranir's complaint pleads this publication (and its own commercial OCL products from 2002–2004) as antedating and invalidating the asserted CAO patents. This is the single most threatening §102(a)/(b) ground (printed publication + public use/on‑sale) against claims 1 and 2, and it predates 2006‑02‑08.
• US 6,458,340 B1 (Ranir LLC, "Desensitizing bleaching gel", 2002‑10‑01) — substantially anhydrous bleaching gels with carbomer thickeners; relevant to the stability/§103 story rather than as a §102 anticipation of the PVP/polyethyloxazoline limitation.
• US 5,989,569 / US 6,045,811 family and US 3,416,527 (Hoef), US 5,326,685 (Gaglio), US 5,310,563 (Curtis), US 5,462,067 (Shapiro) — these are the strip/tray "conformability" references that already defeated similar claims in the family (see the PTACTS claim charts for the '569 patent).

Sources: https://archive.org/download/gov.uscourts.utd.[149468](/patent/149468)/gov.uscourts.utd.149468.1.0.pdf ; https://eureka-patsnap-com.sutd.idm.oclc.org/patent-[US6458340B1](/patent/US6458340B1)

Bottom line

1. US 11,826,445 B2 has exactly one patent citation of record on its face: US 2004/0241110 A1 (Lee, "Jelly‑type tooth‑bleaching patch," pub. 2004‑12‑02). It is the only reference the examiner used, and it is the strongest straight §102 reference against claim 1 because it discloses film + peroxide + solvent + PVP in a "jelly" (gelatinous) form applied to teeth. It does not appear to disclose the six‑month package stability or the "no cracking/breaking on flexure" property, so claim 2 is more naturally a §103 attack (Lee in view of a strip‑conformability reference).
2. The substantive art sits in the 28 "family cited" references, dominated by P&G's low‑flexural‑stiffness strip patents (US 5,894,017; 5,879,691; 6,136,297; 6,045,811; 6,582,708), Colgate US 6,514,483, 3M US 6,322,360, and Ultradent's solid/tray devices (US 6,860,736; 7,056,118; 7,059,857; 7,192,280). Each discloses the backing‑strip‑plus‑peroxide‑gel architecture but none is shown, on the citation record, to disclose the closed Markush group "polyethyloxazoline and PVP" — which is the element that carried the claims to issuance.
3. US 4,144,211 (Dow) is the only cited reference that touches poly(2‑ethyl‑2‑oxazoline), and it is not anticipatory: the '445 claims require a peroxide and a dental backing strip, neither of which Dow discloses (Dow uses halogen/interhalogen/pseudo‑halogen oxidants).
4. Priority/date caution: the '445 claims the 2006‑02‑08 date only through a CIP filed 2008‑12‑06. If the "non‑coalescent / visco‑elastic / no cracking‑breaking / PVP" limitations are new matter, the effective date shifts to 2008, which activates several currently‑cited later references (US 7,192,280; US 2005/0255054; CA 2,470,463; US 8,652,446; ES 2,320,321; US 8,840,918; US 8,206,738) as prior art. That is precisely the priority dispute being litigated.

Confidence note: I have verified the citation list and the Lee reference's disclosure directly from the patent text and its PDF. For entries #3–#28 I have the bibliographic data and titles from the family citation record but have not independently read each specification to confirm whether PVP or polyethyloxazoline appears as a thickener; I have marked those §102 conclusions as provisional rather than asserting them as established. Claim/priority-date conclusions are my analysis, not a legal opinion.

I'll ground this analysis in the prior art listed on the patent page and verify key references with live searches.

Now let me verify the oxazoline-related prior art and check for any invalidity challenges against this CAO patent family.

Let me check a few more specific prior-art threads: oxazoline polymers in oral care, and the Ultradent/P&G solid/tray-type whitening devices.

Obviousness Analysis — US 11,826,445 B2 under 35 U.S.C. § 103

Note flagged for the record: this task states the current date as April 26, 2026, while the system timestamp on this session reads 2026-09-28, and the previously generated section was written "as of April 26, 2026." I treat the discrepancy as immaterial to the § 103 analysis (it only affects the litigation/procedural notes at the end, where I use the earlier-stated date), but I am flagging it rather than silently reconciling it.

1. Framework and critical date

• The '445 patent is a continuation, and every claim is asserted to be entitled to February 8, 2006 priority. Because the application was filed October 26, 2022 but carries only pre-AIA priority, I analyze under pre-AIA 35 U.S.C. §§ 102/103, i.e., § 103(a).
• Critical date for § 102(b) art: February 8, 2005. (Even if a court held the device claims to be supported only by the December 2008 CIP disclosure in US 12/329,582, the critical date would be December 6, 2007 — every reference used below still qualifies either way.)
• § 102(e) art: US patents granted on applications filed before February 8, 2006 are prior art as of their filing dates. This matters for the Ultradent and P&G families below.
• PHOSITA: a person with a B.S. in chemistry, polymer science, chemical engineering, or pharmacy and 2–5 years' experience formulating oral-care/dental-whitening gels and adhesive devices — or a DDS with equivalent formulation experience. This is the person charged with the knowledge of over-the-counter whitening strips, tray-type devices, and water-soluble polymer thickeners.
• KSR (550 U.S. 398 (2007)) supplies the governing rationales: substitution of known elements to obtain predictable results; use of a known technique to improve a similar device; and "obvious to try" where the prior art identifies a finite number of predictable solutions with a reasonable expectation of success. See also MPEP § 2144.03.

Important: the family's own earlier members (US 2007/0183987 from US 11/307,463; US 2009/0238779 and US 2016/0216168; US 9,789,036; US 10,646,419; US 11,219,582; and the sibling US 11,826,444) are not available as § 103 prior art — they share the same inventive entity (Jensen & Cao) and the same assignee. Every ground below therefore rests on third-party art, which is exactly what the '445 page's prior-art apparatus supplies.

Prosecution thinness is relevant context: the page's "Patent Citations (1)" shows the examiner cited only US 2004/0241110 A1 (Lee). The '445 page's own "Family Cites Families (28)" and "Similar Documents" lists contain the P&G strip and Ultradent tray-type families that were not applied. Those are the natural § 103 grounds.

2. The claims at issue (recap only)

Two construction points drive the whole analysis:

1. The Markush set is closed but in the alternative. "Selected from the set … consisting of polyethyloxazoline and polyvinylpyrrolidone (PVP)" claims each member separately. A prior-art device with a peroxide gel thickened by PVP alone meets the limitation.
2. "Gelatinous," "non-coalescent," and "visco-elastic" are defined by the patent itself as "resembling gelatin, viscous" and, for "non-coalescent," as material that flexes but does not merge into one body. Any cohesive, permanently deformable polymer gel with a plasticizer/humectant satisfies this language. These words carry little weight as distinguishing limitations.
3. Claim-construction gap (carried over from the verification section): the claims say "polyethyloxazoline," the specification says "poly(2-ethyl-2-oxazoline)." Narrow construction (PEOx specifically) helps the patentee against generic polyoxazolines but hurts it against the Dow art, which claims PEOx by name. Broad construction (polyoxazolines generally) makes every polyoxazoline-based reference applicable. Either way the claim reads on known art.

3. Ground 1 — Claim 1 (and largely claim 2): Lee alone, US 2004/0241110 A1

Lee is the examiner's only citation, so the record already establishes its relevance. Published December 2, 2004 (KR priority May 30, 2003; KR 2004/0103043 published Dec. 8, 2004), it is unambiguously § 102(b) art.

Element map:

Why this is more than a § 103 case: every limitation of claim 1 is disclosed or inherent. Note in particular that Lee's Peroxydone K-30® is a polyvinylpyrrolidone–hydrogen peroxide complex — an adduct that is simultaneously the peroxide source and the PVP component. That is a direct, express teaching of the exact PVP/ peroxide pairing the claim recites, which is fatal to any argument that the PVP branch of the Markush was unpredictable.

Claim 2 additions: Lee discloses "a moisture-proof wrapping paper adhered on the adhesive" (claim 1) — i.e., the composition is packaged and must survive storage; Lee's experimental data show only 1.19–2.38% H₂O₂ loss per hour for the jelly versus 11.38–12.65% for the dry patch (Tables 3–4), i.e., a fortified retention argument; and Lee's patent is directed to overcoming the "irritation" problem, mirroring the '445's long-treatment/mess narratives. The remaining differences (the words "non-fluid," the six-month figure, "particular irregularities") are quantitative/descriptive characterizations of the same jelly-on-film article.

If the patentee avoids anticipation by arguing Lee's PVP is a "coating-forming agent" rather than a "thickener," that is an obviousness argument, not a patentability one. Lee's PVP at 6.5–10 wt% in a water/ethanol jelly with glycerin/butylene glycol necessarily builds viscosity; and the art of record — the '445 specification itself — states that PVP "may be used in this invention with good results." A patentee cannot simultaneously rely on PVP as an operative thickener in its own specification and deny that PVP thickens in the prior art. In re — style admissions of this kind are routinely used against the applicant.

4. Ground 2 — Claim 1 (both branches): Lee (or Ultradent/P&G) in view of the polyoxazoline art

The only element not literally disclosed by Lee is the polyethyloxazoline branch. The '445 page supplies the art:

• US 4,144,211 A (Dow Chemical; Chamberlin & Bangs), cited in "Family Cites Families (28)" — "Novel complexes of polyoxazolines or polyoxazines and halogens, interhalogens or pseudo-halogens." Its claim 3 expressly recites poly(2-ethyl-2-oxazoline). It establishes, as of 1979, that PEOx is a known water-soluble polymer that forms stable complexes with strongly oxidizing halogen species — i.e., it is not merely a generic thickener but one already known to be compatible with aggressive oxidants.
• US 4,481,167 (Dow), found via live search — not on the '445 page, so flagged as extra-record art — "Sanitizing complexes of polyoxazolines or polyoxazines and polyhalide anions." Its specification states that "PEOx:triiodide and PVP:triiodide complexes having high iodine loadings were prepared in aqueous solutions," that PEOx loadings of 10.7% and 16.0% produced homogeneous solutions with viscosities of 11,600 and 67,500 cps, and that the corresponding PVP attempt at 10.5% "resulted in a coagulated multiphase system." This is a direct, express PEOx-vs-PVP comparison in a system containing an oxidizing species, with PEOx taught as the superior thickener/ complexant. That is the strongest single motivation-to-substitute in this record.

Reasons to combine (KSR rationales):

1. Substitution of one known element for another, same purpose, predictable result. PEOx and PVP are both water-soluble, N-containing, film-forming, hygroscopic vinyl-type polymers used as thickeners and complexants. Dow expressly positions them as alternatives and quantifies PEOx's advantage.
2. Finite, identified, predictable solutions. A formulator seeking a peroxide-resistant thickener in 2005 had a short, enumerated list (carbomer/Carbopol, PVP, PVA, PEG, silica, PEOx). Where a claim recites a small closed set and the art teaches that set's members as equivalents, the claim is obvious ("obvious to try" with a reasonable expectation of success).
3. Predictable viscosity/viscoelasticity. Dow reports PEOx solutions at 11,600–67,500 cps — squarely within the '445's own recited target range of 1,000–200,000 centipoise — so the rheological result the '445 asserts ("very viscous gels") was known.

The specification's "surprising compatibility" assertion gets no weight absent data. The '445 states that PEOx is "surprisingly" compatible with peroxide, but supplies no comparative stability data for PEOx versus Carbopol, PVP, silica, or PEG. Unsupported assertions of unexpected results cannot rebut a prima facie case. (Note the internal inconsistency, flagged for the file: the specification simultaneously calls PVP "not as preferred" and says it "may be used in this invention with good results" — the latter is an admission that the PVP branch of the Markush works.)

5. Ground 3 — The "tray"-structure limitations are squarely old: Ultradent family

The '445 specification itself concedes that the prior art contained "more rigid or solidified treatment compositions that are set into a tray or onto a backing material," that these "resist flow [and] tend to stay on the backing strip or tray," and that the only deficiency was that "they do crack and break if flexed." That is an admission that every structural element of the claims — flexible backing + non-fluid, cohesive treatment composition conjoined to it, conformable to a dental arch — was known, with the asserted (but unquantified) difference being elasticity.

The page's "Family Cites Families (28)" and "Similar Documents" lists supply references that embody that admission:

⚠️ Date caveat: the '445 page displays the grant dates (2006-02-14; 2006-03-14; 2007-03-20) for 6,997,708 / 7,011,523 / 7,192,280, which post-date February 8, 2006. Their availability depends on their application filing dates (§ 102(e)), which I did not verify on the patents' face pages. The family listing associates several of these with the Ultradent 2003-05-23 priority cluster (alongside US 6,860,736), which would place them comfortably before the critical date — but this must be confirmed before any ground is actually pleaded. If any of them files after February 8, 2006, it drops out (though the P&G Sagel family, published 1998–2002, does not have this problem).

Combination: Ultradent supplies the device architecture — flexible backing, non-fluid cohesive composition, conformability — and Lee/Dow supply the chemistry (PVP or PEOx + peroxide + solvent in a jelly). The motivation is the very one the '445 recites as the problem to be solved: prior solid compositions "do crack and break if flexed." Using an elastic, hygroscopic water-soluble polymer gel (rather than a brittle dried solid) to obtain the flexibility the art already demanded is a predictable variation with a reasonable expectation of success.

6. Ground 4 — The P&G Sagel strip family + PEOx art

The page's "Family Cites Families (28)" lists the whole P&G strip chain: US 5,894,017; US 5,879,691; US 6,045,811; US 6,136,297; US 6,582,708; and US 2002/0018754 A1 ("Shapes for tooth whitening strips"). These are 1997–2002 publications — well before the critical date — and they teach:

• a strip of material having low flexural stiffness that substantially conforms to the curvature of the wearer's mouth, gaps between adjacent teeth, and the shape of a tooth by permanent deformation under light pressure (the same conformity concept claim 1 asserts);
• a tooth-whitening substance (including hydrogen peroxide) on the strip that is a "viscous fluid or gel" with extrusion resistance — i.e., the cohesive, non-running character the claims call "gelatinous, non-coalescent";
• commercially packaged, shelf-stable strips.

Notably, the intellectual-property posture inverts here: the PTAB petitions surfaced in my search show Cao Group itself petitioning for IPR of P&G's US 5,989,569 (the "permanently deformable strip" patent) over Hoef/Gaglio/Curtis/Shapiro. Cao there argued that a flat strip deformed to fit the dental arch, carrying a peroxide gel, was obvious. That same reasoning cuts against the '445's claim 1 conformity limitations — a prosecution/ litigation estoppel-flavored argument a defendant can deploy.

Combined with Lee (chemistry: peroxide + PVP + solvent in a jelly on a film) and Dow US 4,144,211 / 4,481,167 (PEOx as a known, superior alternative to PVP in oxidizing systems), every limitation of claims 1 and 2 is met, and the motivation is the shared, long-recognized objective of keeping a bleaching gel in place on uneven teeth without extrusion, migration, or mess.

7. Claim 2's "six months at room temperature in a package" — why it is not a saving limitation

Three independent routes make the stability limitation obvious:

1. Known peroxide stabilizers. The page lists AU 2002314772 A1 (Biofx) — "Stabilizing peroxides with stannous halides" in the family citations; Lee uses sodium stannate (1 wt%) as a peroxide stabilizer and EDTA-type chelants appear in the '445's own additive list. Adding a known stannate/chelate stabilizer to a PEOx or PVP peroxide gel to reach a commercially acceptable shelf life is routine optimization of a recognized result-effective variable.
2. Known stable polymer–peroxide complexes. PVP–H₂O₂ complexes (Peroxydone, in Lee) and the Dow PEOx–halogen/polyhalide complexes are both isolated, shelf-stable solids. If a stable PEOx/oxidant complex is known, a stable PEOx/H₂O₂ gel is not a patentable surprise.
3. Commercial practice. Packaged, shelf-stable whitening strips (P&G), patches (LG's ES 2320321 T3 / US 8,652,446 and US 2004/0241110 with its moisture-proof wrapping) and tray devices were all marketed with multi-month shelf lives. The six-month figure is a statement of intended result, and the claims do not recite any structural or compositional feature — no specific MW, no concentration, no stabilizer, no packaging structure — that achieves it. A result limitation with no disclosed mechanism adds nothing.

8. Secondary considerations / expected rebuttals

9. Caveats, uncertainties, and what would change this assessment

• Everything above is an advocate's § 103 theory, not an adjudicated result. No IPR, reexam, or invalidity judgment on the '445 patent was found in my searches. The grounds are constructed from the '445 page's own prior-art apparatus.
• The only reference I positively confirmed in full text (Lee, US 2004/0241110 A1 — claims, tables, examples) was retrieved and quoted directly. US 4,144,211's claim 3 to poly(2-ethyl-2-oxazoline) was confirmed in the retrieved text. US 4,481,167's PEOx-vs-PVP viscosity/coagulation comparison was retrieved via a Justia mirror of the patent — it is not on the '445 page's lists and should be pulled from the patent's own face/columns before use.
• Filing dates for US 6,997,708; 7,011,523; and 7,192,280 were not verified. Their § 102(e) availability turns entirely on that.
• Term/expiry (from the earlier section): the page lists "Expired – Lifetime, expires 2026-02-08." If that is right, the patent lapsed before either stated "current date," which materially changes remedies but not the § 103 analysis. Two confirmations are needed: (a) whether any PTA extended the term (the file wrapper shows a non-final action June 21, 2023, and a response July 3, 2023 — a rapid allowance, so PTA is likely small), and (b) whether a terminal disclaimer was filed over the sibling US 11,826,444 (same issue date, same 2026-02-08 expiration — a strong indicator one exists, which would also moot a non-statutory double-patenting attack and cap any recovery).
• Procedural posture if invalidity is to be tested: the patent was asserted against many defendants beginning February 2024 (N.D. Ill. Schedule A cases), so 35 U.S.C. § 315(b) one-year bars may already have run for early-served defendants. For parties served later (e.g., the Nov. 24, 2025 D. Del. action against Ivoclar Vivadent, 1:25-cv-01430, per the Stanford NPE database), an IPR on the Lee + Dow + Ultradent combination would be timely if filed within a year of service. IPR remains available on an expired patent, but the value is retrospective only.
• Reference-date hygiene: because the '445 claims 2006 priority, all art must be verified as of the correct critical date. Lee's December 2, 2004 publication clears § 102(b) on its face; the P&G family (1997–2002) clears it easily; the Ultradent items need the filing-date check noted above.

Bottom line: Claims 1 and 2 of US 11,826,445 are, on the face of the art listed on the patent's own page, vulnerable to § 103(a) challenge under at least four independent grounds — most powerfully Lee (US 2004/0241110) alone or in view of US 4,144,211 / US 4,481,167, and the P&G Sagel strip family in view of the same polyoxazoline art. The weak points in the prior art coverage are (i) the late filing dates of the Ultradent "solid composition" patents and (ii) the absence of any single reference expressly pairing poly(2-ethyl-2-oxazoline) with hydrogen peroxide in a dental device — a gap that a district court or the Board would likely bridge with the Dow substitution rationale, but which is the patentee's best (and largely unsupported) line of defense.