US 11826444

I'll search for authoritative details on this specific patent number.

Let me check litigation and any appellate activity specific to this patent.

US 11,826,444 B2 — "Peroxide gel compositions"

Bottom line: I confirmed this patent number resolves to a real, granted US patent owned by Cao Group, Inc. I found no Federal Circuit (CAFC) 2026 docket activity for US 11,826,444. One prominent 2026 appellate/Supreme Court matter involving a "CAO" entity (CAO Lighting, Inc. v. Wolfspeed, Inc., No. 25-1068) concerns different patents (LED patents) and a different company — do not conflate. Two discrepancies I could not resolve are flagged at the end.

Bibliographic data

Important timing note: Google Patents lists an adjusted expiration of 2026-02-08. If accurate, this patent's term has already lapsed as of the current date, notwithstanding the 2023 grant date. Google expressly disclaims that its legal-status data is a legal conclusion — verify against USPTO Patent Center before relying on it. The corporate-family siblings US 11,826,445 B2 (from 18/049,843) and 11,219,582 B2 (from 16/784,582) are reported with the same 2006-02-08 priority, so a parallel or near-term expiration would be expected.

Abstract (as published): A formable dental treatment tray utilizing poly(2-ethyl-2-oxazoline) and a gelatinous active. The active is blended by mixing Poly(2-ethyl-2-oxazoline) with an active such as hydrogen peroxide, carbamide peroxide, sodium perborate, or sodium percarbonate, usually with water or an organic solvent. Peroxide concentrations can reach 30% hydrogen peroxide while maintaining a six-month shelf life at room temperature without peroxide decomposition. Gels are applied to a backing and dried to a gelatinous state; in use the active is hydrated, regains adhesiveness, and the tray is pressed around the dental arch.

Plain-language overview of the independent claims

Claim 1 — dental whitening device (backing + conjoined gel).
A flexible, planar backing strip with two flat sides, plus a "gelatinous, non-coalescent, visco-elastic" dental composition joined to at least part of one flat side. The composition contains (a) a tooth whitening agent, (b) a solvent, and (c) a thickening agent selected from the closed set consisting of polyethyloxazoline and polyvinylpyrrolidone (PVP). When stuck to teeth, both the composition and the backing flex and conform to the dental arch without cracking or breaking.

Claim 2 — dental whitening device (peroxide + shelf-life/performance limitations).
Same backing structure, with a "non-fluid" composition containing a peroxide bleaching whitening agent, a solvent, and the same closed-set thickener (polyethyloxazoline or PVP). The conjoined composition must stay gelatinous, non-coalescent and visco-elastic (i) during storage at room temperature in a package for up to six months, and (ii) after removal from the package and adhesion to the arch — with both composition and backing flexing/conforming to the arch's particular irregularities without cracking or breaking.

Claim 3 — dental whitening composition (stand-alone strip).
A tooth whitening agent plus the same closed-set thickener, where the composition itself is a gelatinous, non-coalescent, visco-elastic substance in the shape of a planar strip. When removed from its package it can be applied directly to the teeth and conform to that individual's arch as it flexes without cracking or breaking.

Claim 4 — a non-fluid dental treatment device comprising the claim-3 composition plus a backing it is placed on.
Claim 5 — the claim-3 composition where the whitening agent is a peroxide.
Claim 6 — the claim-3 composition further comprising a solvent.

Drafting note: the claims recite "polyethyloxazoline," while the specification discusses "poly(2-ethyl-2-oxazoline)"; the claim set also covers PVP as an alternative even though the specification calls PVP "not as preferred." These are literal claim terms and should be read as written.

Litigation posture (district court)

Google Patents lists family litigation in N.D. Ill. (1:24-cv-04903; 1:24-cv-05129), D. Utah (2:24-cv-00498; 2:24-cv-00175), C.D. Cal. (8:25-cv-02074), and D. Del. (1:25-cv-01430). The Stanford NPE Litigation Database maps '444 to two cases: CAO Group Inc v. GuruNanda, LLC, 8:25-cv-02074 (C.D. Cal., filed 2025-09-12) and CAO Group, Inc. v. Schedule A defendants, 1:24-cv-01211 (N.D. Ill., filed 2024-02-12). In Ranir LLC v. CAO Group, Inc., 2:24-cv-00498 (D. Utah), Ranir sought declaratory judgments of non-infringement and invalidity of the '444 patent alongside the '259, '419, and '582 patents; one source lists that case as now closed. I did not find a verified 2026 merits ruling or appeal specifically addressing the '444 patent.

Uncertainty / caveats

1. Claim-text conflict — unresolved. Ranir's 2024 complaint characterizes the '444 patent as having independent claims 1, 2, and 3 and quotes limitations in claims 1, 2, and 3 requiring the composition to have been "dried to an extent that it no longer remains in a state of fluidity." Those drying limitations do not appear in the claim text as fetched from Google Patents (which instead uses "gelatinous, non-coalescent, visco-elastic"). Either the complaint conflates the '444 with a family member, or the claim text I have reflects a different version. I cannot resolve this from the available sources; check the USPTO Patent Center / official patent PDF for the claims of record.
2. No CAFC 2026 activity found for 11,826,444. Absence of a hit is not proof of absence. The 2026 CAO Lighting Federal Circuit/Supreme Court activity is unrelated to this patent and this assignee.
3. Expiration date is stated as 2026-02-08 by Google Patents; treat as a strong indicator, not a legal conclusion, and confirm any maintenance-fee or terminal-disclaimer effects through official USPTO records.
4. The full patent text provided is authoritative over search results per my instructions; where search results (e.g., the Ranir complaint) conflict with it, I have flagged rather than silently resolved the conflict.

Sources: https://patents.google.com/patent/[US11826444B2](/patent/US11826444B2)/en • https://npe.law.stanford.edu/patent/11826444 • https://archive.org/download/gov.uscourts.utd.[149468](/patent/149468)/gov.uscourts.utd.149468.1.0.pdf • https://ai-lab.exparte.com/documents/dct/[4511585](/patent/4511585)/1-24-cv-04903_complaint_exparte.pdf • https://www.relistwatch.com/case/25-1068

I'll search for litigation involving US 11,826,444 specifically.

Let me dig into specific cases and any appellate activity.

Known Litigation Involving U.S. Patent No. 11,826,444

Bottom line: Yes — the '444 is in active enforcement. It is asserted by Cao Group, Inc. (a practicing entity, not an NPE) as one of a five-patent "Sheer White!" peroxide-whitening-strip family — U.S. 10,603,259; 10,646,419; 11,219,582; 11,826,444; and 11,826,445 — which are asserted together in essentially every action. The '444 is also the subject of one declaratory-judgment counterattack by Ranir. No 2026 CAFC appeal, and no IPR/PGR, involving the '444 was found (see §3).

1. Cases involving the '444

Google Patents' own family-litigation feed lists six of these entries (1:24-cv-04903; 1:24-cv-05129; 2:24-cv-00498; 2:24-cv-00175; 8:25-cv-02074; 1:25-cv-01430) plus a "first worldwide family litigation" hit via Darts‑ip.

2. Negative / scope findings

• No case asserting the '444 alone or against Procter & Gamble. The earlier CAO v. Procter & Gamble whitening-strip complaint I retrieved asserts the '259 patent (Crest 3D Whitestrips) and predates the '444's 2023‑11‑28 issuance; on the record reviewed it does not assert the '444. (Case number/filing date not verified.)
• No ITC § 337 action, and no foreign proceeding, involving the '444 surfaced. Note: hits pairing "11826444" with an Irish/UK register or a Czech building permit are unrelated to this patent (e.g., Irish app. 11826444.9 = a lapsed remote-controlled robot patent; the UK Gazette entry "11826444 (B2)" is an unrelated company-registration line).
• The '444 has not been reissued or reexamined on the record reviewed.

3. Appellate (CAFC) and PTAB status

• No 2026 Federal Circuit docket, opinion, or Rule 36 judgment involving U.S. 11,826,444 was found. Nothing in the results shows an appeal perfected from any of the seven district-court cases above. This is a "not found," not a verified negative — it requires a PACER/CAFC docket check to confirm.
• No IPR, PGR, or CBM naming the '444 was found.
• Do not conflate with the 2026 Supreme Court/Federal Circuit activity that surfaces alongside "CAO": that is CAO Lighting, Inc. (e.g., CAO Lighting, Inc. v. Wolfspeed, Inc., cert. denied 2026, on Rule 36 affirmances and Loper Bright) — a different entity and different patent family.

4. Flags and discrepancies you should know about

1. Source-coverage conflict. The Stanford NPE Litigation Database page for patent 11826444 lists only two cases (GuruNanda and 1:24-cv-01211). Google Patents and the complaints themselves show at least seven. The NPE database under-reports here; treat it as non-exhaustive.
2. Damages figures differ between the two N.D. Ill. default judgments ($1,518,750 per defendant in 1:24-cv-01211 vs. $1,650,000 in 1:24-cv-05129). Both are from reproduced PACER order text via secondary aggregators; verify against the originals.
3. Possible claim-citation error in the Ranir complaint. Ranir's ¶¶ 135–136 quote, as limitations of '444 claims 1 and 2, "[T]he dental composition having been dried to an extent that it no longer remains in a state of fluidity," and as a limitation of '444 claim 3, "[A] step of drying the bleaching gel on the backing material until the bleaching gel is no longer in a state of fluidity and has attained a non-coalescent gelatinous state." Neither quote appears anywhere in the issued '444 claims as given in the authoritative patent text (claim 3 is a composition claim reciting no method step). That "drying step" language is characteristic of the '582 ('Dental treatment compositions…') claim set. This looks like a citation/OCR mismatch in the complaint or the aggregator's reproduction — worth checking against the complaint exhibit itself, because it goes to the heart of Ranir's non-infringement theory (no drying step).
4. Ranir case status unresolved. One aggregator returns "Closed"; the PACER-derived Justia docket stops at 2024-08-20. Given the Walmart case ended in a stipulated dismissal with prejudice and the Ranir case is the mirror-image DJ action by Walmart's supplier (represented by the same Greenberg Traurig/Warner Norcross team as Walmart), a coordinated resolution is plausible — but I cannot confirm it.
5. Characterizations to discount. The "LED teeth-whitening portfolio" framing applied to this five-patent set comes from a third-party litigation blog and is not supported by the '444 — which says nothing about LEDs. The '444 claims are drawn to a gelatinous, non-coalescent, visco-elastic peroxide composition/device, thickened by a closed Markush set of polyethyloxazoline and PVP.

5. Key sources

• Google Patents, US11826444B2 (family litigation feed): https://patents.google.com/patent/US11826444/en
• Stanford NPE Litigation Database, patent 11826444: https://npe.law.stanford.edu/patent/11826444
• Case page, CAO Group v. Ivoclar Vivadent: https://npe.law.stanford.edu/case/[308900](/patent/308900)
• Ranir complaint, D. Utah 2:24-cv-00498-RJS, Doc. 1 (2024-07-16): https://archive.org/download/gov.uscourts.utd.[149468](/patent/149468)/gov.uscourts.utd.149468.1.0.pdf
• CAO complaint excerpt, N.D. Ill. 1:24-cv-04903: https://ai-lab.exparte.com/documents/dct/[4511585](/patent/4511585)/1-24-cv-04903_complaint_exparte.pdf
• CAO v. Walmart case page: https://www.docketalarm.com/cases/Utah_District_Court/2--24-cv-00175/
• Justia docket, Ranir v. CAO: https://dockets.justia.com/docket/utah/utdce/2:2024cv00498/149468

I'll verify the structured ODP "no proceedings" finding against public PTAB/CAFC sources before writing.

Now let me check for any petitions against the sibling patents (pattern signal) and confirm no PTAB filings by the recent district-court defendants.

Let me run two final disambiguation checks — any challenge to the sibling patents, and any 2026 filing.

Proceedings overview

One proceeding count: zero. The USPTO Open Data Portal structured feed returns no AIA trial proceedings on U.S. 11,826,444 — no IPR, no PGR, no CBM — and that finding survived my independent web checks (details and disambiguation below). The defensive posture this gives a defendant is therefore not "hardened by surviving IPR" and not "killed in IPR," but a third thing a defendant must plan around: the patent is completely untested at the Board, so there is no FWD to cite, no cancellation to rely on, and no § 315(e)(2) estoppel binding anyone — the entire invalidity fight is happening, and has been happening since 2024, in district court.

Verification of the structured "no proceedings" finding

I treated the ODP block as canonical and then tried to falsify it. It held.

Method caveat, stated plainly: I could not query the PTAB E2E / PTAB API directly in this session, and the ODP ingest lags recent filings. A "not found" is not a verified negative. Confirm the null result at PTAB E2E and via the USPTO Patent Center before relying on it in a filing or a damages narrative.

⚠️ Disambiguation — the "'444" hits you will find are NOT this patent

This is the single biggest trap in this analysis. Public search for "IPR + 444" returns a wall of confident, wrong results. None of the following concern Cao Group's peroxide gel patent:

Also do not conflate the Unified Patents appearance in the table above with this patent: Unified is a defensive aggregator that filed against Dragon's VCR patent, not against Cao. There is no Unified/RPX/AST/LOT involvement in the '444's chain (consistent with the earlier ownership finding).

The PTAB connection that does exist — and it's Cao on the other side

Not a proceeding against the '444, but directly relevant to how a defendant should read Cao's PTAB sophistication:

What this tells you: Cao has litigated at the Board as a petitioner and lost one on the merits of petition drafting. It is not a first-time PTAB participant, and the family's 2006 priority date means Cao is used to defending against art that long predates the strip category. Do not assume a technically sloppy petition will be waved through.

Strategic summary

Claim status: claims 1–6 are all UNTESTED. There is no claim-level PTAB record of any kind. Nothing in the '444 has been canceled, confirmed, or even instituted upon. As of 2026-09-28, the claims of record remain: independent claims 1, 2, 3 and dependent claims 4, 5, 6, exactly as set out in the authoritative patent text. If a demand letter cites claim 1, there is no FWD you can point to and say "that claim is dead." Conversely, there is no FWD you have to distinguish.

Estoppel landscape: clean slate — with one important asymmetry. Because no IPR has ever been instituted on the '444, § 315(e)(2) estoppel binds no one as to this patent. Any defendant may raise any ground. But the asymmetry that matters is statutory, not estoppel-based: IPR grounds are limited by § 311(b) to patents and printed publications. The invalidity theories actually deployed against this family in district court are largely the ones an IPR cannot reach:

• § 112 written description / enablement / indefiniteness as to PVP. Ranir's DJ complaint (D. Utah 2:24-cv-00498-RJS, Dkt. 1, ¶¶ 61–64) pleads that the specification contains no PVP formulations at all and that the only two PVP mentions are critical of PVP relative to poly(2-ethyl-2-oxazoline) — while the '444 claims recite a closed Markush set of exactly "polyethyloxazoline and polyvinylpyrrolidone (PVP)." That is a § 112 attack, and § 112 is not available in an IPR. It is only available in a PGR (window now closed) or in district court.
• Prior-art products, not publications. Ranir pleads its own OCL-based whitening products sold since 2004 as invalidating prior art (¶¶ 66–67, 87). Public-use / on-sale art is not cognizable in an IPR. This is a district-court-only weapon.

The practical consequence: the strongest invalidity theories against the '444 are the ones the PTAB cannot hear. A defendant should not assume that the absence of IPRs signals a weak patent; it more likely signals that the sophisticated defendants targeted this family with § 112 and product-based art instead.

Pattern signals.

• No repeat petitioner — no petitioner exists at all.
• No PTAB prosecution aggressive or defensive by Cao as patent owner; its PTAB activity is confined to the 2014 P&G petitions where it was the petitioner.
• No defensive aggregator in the chain.
• Timing signal: the patent has now been asserted across roughly seven district-court matters since 2024-02-12, yet not one IPR has been filed. That pattern is explained less by patent strength than by defendant composition: the bulk of the defendants are defaulting Schedule A e-commerce sellers (who never appear, let alone petition), and the branded defendants chose DJ actions (Ranir) and counterclaims (Ivoclar) over Board proceedings.

Statutory windows — the PGR door is shut, and the clock matters.

• PGR (post-grant review): unavailable. Under § 321(c), a PGR petition must be filed within 9 months of grant. The '444 granted 2023-11-28, so that window closed 2024-08-28. Any purported "PGR" on this patent now is a non-starter.
• CBM: unavailable. The AIA § 18 transitional program sunset on 2020-09-16, and a dental whitening composition is not a "financial product or service" anyway.
• IPR: the only AIA vehicle left, and it is date-sensitive under § 315(b). A petitioner served with a complaint alleging infringement of the '444 more than one year earlier is time-barred. Mapped against today's date:

• Expiration note — flag, do not over-read. Google Patents lists an adjusted expiration of 2026-02-08 for this patent (the earlier sections flagged the same). If accurate, the term has lapsed. An IPR can in principle still be filed against an expired patent (the patent owner simply loses amendment rights), but its practical value collapses to pre-expiration damages and § 285 optics. Verify the expiration and any terminal disclaimer through USPTO Patent Center before building a strategy on it — and note the same 2026-02-08 date would apply to sibling US 11,826,445 B2.

Recommended next steps

1. If you are a defendant currently being asserted against: do not look for PTAB cover, because there is none — the '444 has never been before the Board, in any form. Go straight to the district-court invalidity record that does exist. Ranir's declaratory-judgment complaint is the most developed work product against this family and is public: D. Utah 2:24-cv-00498-RJS, Dkt. 1. Its theories, at ¶¶ 61–64 and ¶¶ 87–89, are:

   • the specification's absence of PVP enablement against claim 1's Markush set (a § 112 ground the PTAB cannot hear), and
   • Ranir's own 2004-era OCL products and the "'277 Publication" / "'510 Publication" as § 102/§ 103 art (the product-based art also being outside IPR reach).

   Note the discrepancy already flagged in the earlier sections: Ranir's ¶¶ 133–136 quote drying limitations as belonging to '444 claims 1–3, but the issued '444 claims as published recite "gelatinous, non-coalescent, visco-elastic" and no drying step. Resolve this against the certified claim text before you adopt Ranir's non-infringement theory — Cao's own opposition brief in the Schedule A case shows Cao actively litigating a "drying step" element, which suggests the citation issue is real and consequential.

2. If you are Ivoclar Vivadent (or advising them): you appear to hold the only live § 315(b) window on this patent (opened ~2025-11-24, closing ~Nov 2026). But weigh it against the § 311(b) limitation: an IPR can only reach patents and printed publications, and the highest-value art against this family (the pre-2006 products and the PVP § 112 theory) is outside that lane. An IPR here buys claim-construction leverage and a stay, not the kill shot.

3. If you are GuruNanda: confirm the exact service date in 8:25-cv-02074 immediately. If it was on or before 2025-09-28, your § 315(b) one-year bar has already run as of today.

4. If you are Ranir: on the record reviewed you were not served with an infringement complaint, so the § 315(b) bar likely does not apply to you — the one-year clock runs from service of a complaint alleging infringement, not from your own DJ filing. That makes Ranir the party best positioned to petition. Verify against the docket, because a Cao counterclaim of infringement, if served, would start the clock.

5. Nothing to docket-watch at the PTAB. There is no institution deadline, no oral hearing date, and no statutory one-year FWD deadline running, because no trial exists. The milestones that matter for this patent are all in district court: the GuruNanda and Ivoclar matters, and the ongoing Rule 69 supplemental proceedings in the N.D. Ill. default judgments.

Bottom line

Zero AIA trial proceedings exist on U.S. 11,826,444 — no IPR, no PGR, no CBM, no FWD, no appeal, no settlement, no estoppel, no panel, and no defensive-aggregator petitioner. Any document you find purporting to show an IPR on a "'444" almost certainly concerns Align's 8,038,444 or Dragon's 7,110,444; verify the patent number before citing it. The counterintuitive takeaway for a defendant is that this is not a hardened patent and not a canceled one — it is an unexamined-at-the-Board patent whose most vulnerable claims have been attacked only with § 112 and product-prior-art theories that the PTAB has no jurisdiction to adjudicate. If you want Board cover on the '444, you will have to create it — and statute, not estoppel, is the binding constraint on what that petition can say.

Sources: Google Patents, US 11,826,444 B2 · PTAB E2E · Unified Patents v. Dragon IP, IPR2014-01252 institution decision · ClearCorrect v. Align, IPR2025-00816 (PO discretionary-denial brief referencing IPR2017-01829 on the Align '444) · CAO Group v. P&G, IPR2014-00796 petition and denial of institution · Ranir DJ complaint, D. Utah 2:24-cv-00498-RJS, Dkt. 1 · Cao's preliminary-injunction opposition re "drying step," N.D. Ill.

I'll verify the assignment record for this patent against public sources before reconstructing the chain.

Let me verify the assignment detail and current corporate status of the assignee.

Let me pin down the assignment correspondent and check for any other recorded conveyances (security interests, liens) in the chain.

Ownership & Assignment Reconstruction — US 11,826,444 B2

Scope note / method: I could not open the Assignment Center UI as an interactive query in this session. The reel/frame, conveyance code, assignors and dates below come from the Google Patents "Legal Events" feed for US 11,826,444 B2, which mirrors USPTO Assignment (AS) records, cross-checked against PTAB-hosted assignment abstracts for the same assignee and against the litigation record. Where a field (notably the correspondent of record for the 2023 recording) could not be verified, I say so rather than infer it.

Inventors

Unusual patterns to note:

• No departure signal. Neither inventor left before assignment; Cao is still the CEO and the assignee is still Cao Group. This is the opposite of the "all inventors depart within 12 months" precursor to a fire-sale.
• Dual-affiliation inventor. Jensen's patent output straddles Cao Group and Ultradent Products — two Utah dental competitors. Ultradent was the plaintiff in a decade of strip-format litigation against Cao's Sheer White! product line, and Jensen appears on both sides' patent estates. That is worth flagging for any inventorship/§ 102(b) inventorship-derivation inquiry, though nothing in the record reviewed shows a challenge on that basis.
• Inventor ranks are small (two), consistent with a single-inventor-concept dental-materials family.

Original assignee

Cao Group, Inc. — a Utah corporation, principal place of business 4628 West Skyhawk Drive, West Jordan, UT 84084-4501. Named as assignee on the face of the issued patent; the same entity is the current assignee (see timeline).

• Does it ship a product embodying the claims? Yes, clearly. The commercial embodiment is the Sheer White!® line — "SheerFilm®" whitening strips described in Cao's own Instructions for Use and SDS as a "gelatinous viscoelastic composition on a flexible and moldable substrate," sold as 20% hydrogen peroxide in-office films and 20% carbamide peroxide take-home strips (24-packs, e.g., Henry Schein item 5950513; Benco item 6051-658). That is a direct product read on the claim-3 "gelatinous, non-coalescent, visco-elastic substance in the shape of a planar strip." Cao's own marketing calls the sheet format "patented."
• Primary line of business: dental devices and materials (whitening films, curing lights, diode lasers, endodontic products, dental cements), plus a separate LED/lighting patent-assertion business. Cao describes itself as a manufacturer of "dental, medical, forensic, and LED lighting products." Product is manufactured by CAO (China) Medical Equipment Co., Ltd. (Langfang, Hebei) for the U.S. distributor Cao Group, Inc.
• Current status: Operating. No bankruptcy, dissolution, or acquisition found. No Chapter 7/11 filing surfaced. Cao is actively litigating as plaintiff in 2024–2025 (see below), and its practice is staffed and in-house-counseled (Kelly Preece, General Counsel; jim.farmer@caogroup.com on prosecution correspondence).
• Assertion posture: Cao is a serial plaintiff — it has run campaigns against P&G (whitening strips), GE Lighting/Current (LED, via Cao Lighting, Inc., $2M Delaware jury verdict Feb 2023), Signify, Feit, Osram, Cree, and now against Ivoclar Vivadent, GuruNanda, and dozens of Amazon sellers. It is a practicing entity on both sides.

Assignment timeline

Finding up front: the '444's own legal-events record contains exactly one recorded assignment. There is no post-issuance assignment, no security agreement, no merger, no change-of-name, no release, and no corrective assignment recorded against US 11,826,444. That is itself the headline: the patent has never left Cao Group.

2015-05-28 / 2015-05-29 (executed) / recorded 2023-09-11 — Reel 064860 / Frame 0918

• Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS) (AS)
• Assignor: Jensen, Steven D. (signed 2015-05-28) and Cao, Densen (signed 2015-05-29)
• Assignee: CAO GROUP, INC., UTAH (West Jordan, UT)
• Correspondent: ⚠️ Not verified. I could not retrieve the correspondent of record for reel 064860/0918. For context on the assignee's historical filing habits (not a finding as to this reel): Cao's early assignments were recorded through Daniel P. McCarthy, Parsons Behle & Latimer, 201 South Main Street, Suite 1800, Salt Lake City, UT 84111 (e.g., Reel 012126/0261; Reel 017962/0419), while Cao's prosecution correspondence address was consistently in-house (Kelly Preece, General Counsel, CAO Group, 4628 W Skyhawk Dr). Do not attribute either to this reel without pulling the document.
• Context: Title clean-up, inventors → original operating assignee. The instrument was executed in May 2015, ~16 days after the 14/710,416 continuation was filed (2015-05-12), but was not recorded until 2023-09-11 — three days after the issue fee was paid (2023-09-08) and ~2.5 months before grant (2023-11-28). This is a routine pre-issuance perfection of the chain of title under 37 CFR 3.71/3.73, not an arm's-length transfer.

No other recorded assignments. Confirmed absence of: assignment to any "IP Holdings / Licensing / Ventures" entity; security interest or collateral assignment; merger; change of name; and any post-issuance conveyance through 2026-09-28.

Timeline diagram

timeline
    title Ownership of US 11826444
    2006 : Priority application filed Feb 8
    2015 : Inventors executed assignment to Cao Group
    2023 : Assignment recorded reel 064860 frame 0918
         : Patent granted Nov 28
    2024 : First infringement suits filed
    2025 : Suits against GuruNanda and Ivoclar

NPE / troll-pattern signals

Verdict

Operating-company assertion.

The chain contains a single recorded conveyance — Reel 064860/0918, executed 2015-05-28/29 and recorded 2023-09-11 — moving the '444 from its two named inventors to Cao Group, Inc., a Utah operating corporation that manufactures and sells the claimed subject matter as the Sheer White!® SheerFilm® hydrogen-peroxide whitening strip (Cao's own SDS/IFU describe it as a "gelatinous viscoelastic composition on a flexible and moldable substrate"), and that has asserted the patent since 2024-02-12 against product-selling competitors (Ivoclar Vivadent, GuruNanda) and Amazon/e-commerce sellers. No NPE in the enumerated list appears in the chain, no shell or licensing entity ever takes title, and the patent has never been transferred post-issuance. The one honest caveat for a defense-side reader: Cao's enforcement style — mass Schedule A joinder, asset freezes, and trebled default judgments against absent overseas sellers ($1,518,750 per defendant in 1:24-cv-01211; $1,650,000 in 1:24-cv-05129) — produces NPE-like optics even though the plaintiff is the product maker. Judge the entity on the record, and the record says practicing entity.

Cross-check flags carried forward:

1. Term. Google Patents lists this patent as "Expired – Lifetime, expires 2026-02-08" (20 years from the 2006-02-08 priority filing of 11/307,463). If accurate, the patent has already lapsed even though it granted 2023-11-28 — the same date was flagged in the earlier sections and would apply to sibling US 11,826,445 B2. Verify through USPTO Patent Center before relying on it; ownership is moot if the term has run.
2. Claim-text conflict (unresolved from prior sections). Ranir's ¶¶ 133–136 attribute "drying to an extent that it no longer remains in a state of fluidity" limitations to '444 claims 1–3; the issued claims recite "gelatinous, non-coalescent, visco-elastic" and no drying step. The ownership chain does not resolve this, but it matters because it drives Ranir's non-infringement theory.
3. Correspondent gap. The Assignment-Center correspondent for Reel 064860/0918 is unverified in this session. If you need to know who recorded the 2023 title clean-up, pull the reel image at USPTO Assignment Center (search patent number 11826444) — that is the one field I could not confirm and the one that most often exposes a repeat-player filer.

Verification link: USPTO Patent Assignment Search — 11826444 · Assignment Center · Google Patents legal events, US 11,826,444 B2 · Stanford NPE Database, patent 11826444 · CAO Group v. GuruNanda docket · Sheer White! In-Office IFU · Sheer White! SDS · CAO Group corporate statement

I'll verify the citation record for US 11,826,444 against USPTO/public sources and pull details on each cited reference.

Let me try to confirm the '444's own "References Cited" front-page data and check for any non-patent literature citations.

Prior Art Assessment — US 11,826,444 B2 ("Peroxide gel compositions")

Task: identify the prior art cited for US 11,826,444 and map each reference to the claim(s) it potentially anticipates under 35 U.S.C. § 102.

Method / honesty note up front. I was not able to open USPTO Patent Public Search or Patent Center as a live interactive query in this session. What follows is built on (a) the authoritative full text of the '444 supplied in this analysis, which contains the patent's own citation tables, and (b) targeted verification searches on each reference's text and dates. Google Patents' machine-readable citation fields mirror the USPTO "References Cited" (PTO-892/IDS) record but are not always complete — so where the record is thin I say so rather than fill the gap. Every patent number below is reproduced literally as it appears in the record; none has been auto-corrected.

0. Threshold: what "the patent citations for 11826444" actually comprises

There are two different citation sets in the '444 record, and conflating them is the single most common error in a prior-art review of this family:

Set A is what the question literally asks for; Set B is what actually matters for invalidity. I cover both, in that order, so the distinction is preserved.

⚠️ Data-completeness flag (new). The '444's Google record shows only 2 patent citations, while the sibling US 10,646,419 B2 carries a ~30-reference front page (Dow '211; P&G '453/'017/'811/'297/'708/'426/'199; Ultradent '736/'118/'857; Colgate '483; Dentsply '923; Chen '408/'316; Mitra '038; Kim '401/'802; 3M '566/'360; Micron '629; Albemarle '089; Nippon Shokubai '930). Two explanations are possible — a genuinely sparse IDS in 17/659,473, or incomplete data in the aggregator — and I cannot distinguish them from the sources available. Pull the '444's own PTO-892 and IDS from Patent Center before treating Set A as exhaustive. This is a material gap, not a cosmetic one: if the '444's IDS carried the full family list, then every reference in Set B is also of record in the '444.

1. The two references cited on the face of the '444 (Set A)

1.1 — US 2004/0241110 A1 (Lee) — the primary reference

Brief description (verified against the published text). A tooth-bleaching patch comprising three layers: (i) a film (worked example: a PET film), (ii) a jelly-type adhesive applied on the film, and (iii) a moisture-proof wrapping paper adhered over the adhesive ([0009]). The adhesive expressly contains:

• Peroxide — hydrogen peroxide, carbamide peroxide, calcium peroxide, sodium percarbonate, sodium perborate, tetrasodium pyrophosphate peroxide, hydrogen peroxide 2-pyrrolidinone 1-ethenyl-homopolymer, PVP-VA-hydrogen peroxide®, Gafquat HS-100-hydrogen peroxide®, PVP-AA-hydrogen peroxide®, Ganex-hydrogen peroxide® ([0014], claim 4);
• Peroxide stabilizer — sodium stannate, alkylarylsulfonates, Spans, Tweens ([0015]);
• Coating-forming agent expressly including "polyvinyl pyrrolidone" (molecular weight stated at 400,000–1,200,000), polyvinyl alcohol, sodium alginate, and the PVP–peroxide adducts ([0019], claim 9);
• Coating-forming aid (cellulosics, gums, poloxamer, carrageenan…) ([0020]); wetting agent — polyethylene glycol, glycerin, polypropylene glycol, sorbitol ([0021]); plasticizer; sweetener; optional crosslinking agent/aid ([0028]).

Worked Example 1 is, in substance, a hydrogen-peroxide/PVP/water/ethanol/glycerin jelly coated onto PET film; Example 3 and Example 4 use PVP at 0.5 wt% and 10 wt%; Example 1 of the second table uses urea hydrogen peroxide (8 wt%). The stated object is a patch "flexibly attached to teeth in accordance with the teeth shape" that keeps bleach in contact with the teeth at sufficient concentration for sufficient time.

§ 102 analysis (pre-AIA § 102(b) — published 2004-12-02, more than one year before the 2006-02-08 priority date):

Bottom line on Lee: it is a § 102(b) reference that reads directly on the PVP species of the '444's Markush set, in a flexible film-backed tooth-bleaching patch format. The '444 claims PVP as one of only two permitted thickeners, and the specification itself concedes PVP "may be used in this invention with good results." That concession, combined with Lee, is the single largest § 102 exposure in the patent. The PEtOx branch (polyethyloxazoline) is not disclosed by Lee — that branch requires a § 103 combination (see § 3, item 1).

1.2 — US 2009/0130624 A1 (Sun) — the second face citation

Brief description (verified). A method and kit for chair-side fabrication of a light-curable night guard/bite splint. The arch material is a polymerizable acrylic composition (polymerizable acrylic compound, colour-change cure indicator, particulate filler, photoinitiator), moulded to the dental arch, partially cured in the mouth and fully cured outside it. The kit includes a U-shaped dental guard in a flexible silicone tray, a "U-shaped backing film, for example, Parafilm (hydrocarbon wax film)" placed over the guard, and a release liner, all vacuum-sealed in a light-protective package. Claims are directed to flexural modulus/strength (e.g., <250,000 psi modulus, <7,000 psi strength at 37 °C).

§ 102 analysis — and the key point:

• Against any claim entitled to the 2006-02-08 priority date, Sun is not § 102(b) art (published 2009-05-21) and not § 102(e) art (its earliest U.S. filing is 2008-11-20, after 2006-02-08). Sun anticipates nothing.
• Sun becomes available only if a claim loses the 2006 benefit date. The realistic trigger: the '582 (a continuation-in-part filed 2008-12-06) added subject matter, so any claim whose support first appears in the 2008 CIP rather than in 11/307,463 takes a 2008-12-06 effective date — which is 16 days after Sun's 2008-11-20 filing date. In that narrow scenario Sun becomes § 102(e) art.
• Even then, Sun is a poor anticipation reference: it discloses no peroxide, no polyethyloxazoline, no PVP, and no peroxide-bearing gelatinous whitening composition. Its acrylic arch material is cured-solid, not "gelatinous, non-coalescent, visco-elastic."
• Its real value is as a § 103 element-supplier: it is a same-field reference teaching (a) a Parafilm backing film — the very backing material the '444 specification names — (b) vacuum-sealed moisture-protective packaging, and (c) a dental device that conforms to the arch without cracking. That is direct support for a motivation-to-combine argument on the backing/packaging limitations of claims 1, 2 and 4.

2. § 102 claim-mapping summary for Set A

No claim is anticipated by Sun. Claims 1, 4, 5 and 6 are potentially anticipated by Lee.

3. The family citations (Set B) — the 27 references that do the real work

These are the references cited in the shared family record (they appear on the '419's front page and in the family's IDS). If the '444's own IDS carried them — which the data gap in § 0 leaves unresolved — they are all "of record" for the '444 as well. Grouped by function, each with the claim(s) it bears on.

3.1 The polymer-chemistry keystone — poly(2-oxazoline) in oxidizing aqueous media

3.2 Peroxide whitening gel on a flexible strip, stable in thin-layer storage

3.3 Hydrogel whitening compositions on the PVP (poly-N-vinyl lactam) platform

3.4 Substantially solid / gelatinous, non-fluid, tray- or strip-borne treatment compositions

3.5 Oxazoline polymer synthesis, dental materials and peroxide stabilisation

4. Non-patent literature

5. What is not prior art (avoid these errors)

• US 2009/0130624 A1 (Sun) — despite being on the face of the '444, it cannot anticipate the 2006-priority claims. Its presence on the front page is a data point about the examiner's search, not a § 102 threat.
• Everything dated after 2005-02-08 (the § 102(b) critical date if the claims take the 2006-02-08 benefit) — including US 2010/0028829 A1, WO 2015/053808 A1 / CN 111658213 B (Ultradent wax-based compositions), US 2016/0175207 A1 (Jensen, tripolyphosphate whitening film), US 2023/0210731 A1 (Cao Group, reduction-resistant hydrogel thickeners), and the Microban consumer-goods family. These are "Similar Documents"/forward citations, not § 102 art against the present claims.
• The "Families Citing this family (24)" list (Kerr curing lights, Align, Microban, etc.) — these cite the family; they do not precede it.

6. Bottom line, claim by claim

The single most important structural fact for any § 102 analysis of this patent: the claims recite a closed two-species Markush — "polyethyloxazoline and polyvinylpyrrolidone (PVP)" — and the specification itself states that "polyvinylpyrrolidone ('PVP') may be used in this invention with good results." A claim to "A or B" is anticipated by art disclosing either species. Lee (US 2004/0241110 A1) discloses the PVP species, with peroxide, in water/ethanol, in a flexible film-backed dental patch that conforms to the teeth shape. That is the anticipation case the patentee must answer, and it is a § 102(b) case, not a § 103 case.

7. Flags, discrepancies, and one prior flag now partially resolved

1. Citation-set completeness (new flag). The '444 shows 2 face citations; the sibling '419 shows ~30. I cannot tell whether the '444's IDS was genuinely sparse or whether the data is incomplete. Pull the '444's PTO-892/IDS from USPTO Patent Center — this materially changes which of Set B is "of record" for the '444.

2. The "drying step" claim-text conflict — now largely resolved, and it cuts toward the earlier suspicion. The Ranir DJ complaint (D. Utah 2:24-cv-00498-RJS, Dkt. 1) pleads, at ¶¶ 78 and 97, that the drying limitation reads: "[W]herein the dental composition is dried after being applied on the strip of backing material," and attributes it to claims 1, 14, 27 of the '259 patent and claims 1, 16, 28 of the '419 patent. It does not appear as an '444 limitation in the passages I retrieved. That is consistent with the earlier sections' conclusion that the ¶¶ 133–136 attribution of a "drying" limitation to '444 claims 1–3 was a citation/aggregation error. The '444's claims, as published, recite "gelatinous, non-coalescent, visco-elastic" and no drying step — so a non-infringement theory built on the absence of a drying step does not travel to the '444.

3. § 112, not § 102, is where the PVP branch is weakest for the patentee. Ranir's ¶¶ 61–64 plead that the family contains no PVP formulations at all and that the only two PVP mentions are critical of PVP relative to poly(2-ethyl-2-oxazoline) — while the '444 claims PVP as one of two permitted thickeners. § 112 grounds are not available in an IPR; they must be tried in district court. Any § 102 analysis of the PVP branch should be paired with this § 112(a)/§ 112(b) attack, not substituted for it.

4. Priority-date exposure is the gateway to Sun. If any '444 claim's support first appears in the 2008-12-06 CIP (12/329,582) rather than in 11/307,463 (2006-02-08), the effective date moves past Sun's 2008-11-20 filing date and Sun becomes § 102(e) art. Even then, Sun is a weak anticipation reference and a moderate § 103 reference (Parafilm backing; vacuum-sealed packaging).

5. Term. Google Patents records the '444 as "Expired – Lifetime, expires 2026-02-08", i.e., 20 years from the 2006-02-08 priority filing. If accurate, the term has lapsed — which affects the practical value of any invalidity challenge but does not change the § 102 analysis, and which the Office's own term calculation (measured from 2006-02-08) does not by itself prove written-description support for these claims. Verify through Patent Center.

6. Verification status of what I checked. I confirmed the full published text and dates of US 2004/0241110 A1 (Lee) and US 2009/0130624 A1 (Sun), and the text of US 4,144,211 A (Dow) as reflected in the companion Dow specification. For US 6,582,708 B1 (P&G), the Ultradent group, the Corium/Topchiev hydrogel patents, and the remaining Set B items, I relied on titles, dates, assignees and published abstracts/claims as they appear in the citation listings and did not open every full text. Confirm the gelling-agent and thickener lists of P&G '708 and Corium '918 before relying on them for a § 102 anticipation position — in both cases the entire anticipation argument on the PVP branch turns on whether the reference's polymer list reaches PVP in a peroxide strip.

Sources: US 11,826,444 B2 (authoritative full text and citation tables) · US 2004/0241110 A1, Lee, "Jelly-type tooth-bleaching patch" (full text) · US 2004/0241110 A1 (PDF, including Table 1 and claims) · US 2009/0130624 A1, Sun, "Methods and kits for making flexible dental guards" · US 2009/0130624 A1 (PDF) · US 10,646,419 B2 front page (family "References Cited" list) · US 9,789,036 B2 family page (family citations, 27) · Ranir LLC v. CAO Group, Inc., D. Utah 2:24-cv-00498-RJS, Dkt. 1 (2024-07-16) · USPTO Patent Center

I'll ground the analysis by pulling details on the key prior-art references listed on the patent page.

Obviousness Analysis — US 11,826,444 B2 ("Peroxide gel compositions")

Sources used: the prior-art listings on the patent page (https://patents.google.com/patent/US11826444/en) — examiner citations, "Family Cites Families (27)," "Families Citing this family," and "Similar Documents" — plus verification searches on the key references. Where I could not open a reference's full text, I say so.

Threshold caveat: This is a technical invalidity sketch, not legal advice or an opinion of counsel. Claim construction is a prerequisite; several limitations ("non-coalescent," "gelatinous," "polyethyloxazoline") are outcome-oriented and are construed in light of the specification's own definitions.

1. The claims to be assessed

Two structural observations drive the whole analysis:

1. The claims are a two-species Markush. "Polyethyloxazoline" and "PVP" are the only permitted thickeners. A claim to "A or B" is anticipated/obvious if the prior art discloses either species in the recited environment — so the PVP branch is the soft underbelly, and the PEtOx branch is the only place the patent has room to argue.
2. Claim 3 requires no peroxide and no backing. A planar-strip whitening gel thickened with either polymer reads on the broad genus of commercial whitening strips.

Applicable law: the application claims benefit back to US 11/307,463 (filed 2006-02-08), so the pre-AIA §§ 102/103 framework governs (Graham v. John Deere; KSR v. Teleflex). References published more than one year before 2006-02-08 are § 102(b) art; references with earlier U.S. filing dates can be § 102(e)/§ 103(a) art.

Level of ordinary skill (POSITA): a bachelor's degree in chemistry, polymer science, pharmacy or dental materials, plus ~2–4 years formulating oral-care/peroxide gels and adhesive dental devices, or equivalent — with ready access to supplier literature for commercial water-soluble polymers (the '444 itself notes that poly(2-ethyl-2-oxazoline) is "commercially available in 50,000, 200,000 and 500,000 M.W." under the Aquazol tradename).

2. The prior art of record, grouped by function

Group I — Jelly/adhesive peroxide patch on a film (the closest art)

• US 2004/0241110 A1 (Lee, "Jelly-type tooth-bleaching patch"), pub. 2004-12-02; priority 2003-05-30; family KR 100507675 B1. This is the only substantive examiner citation besides Sun. It discloses "a film, an adhesive applied on the film, and a moisture-proof wrapping paper." The adhesive contains peroxide (expressly hydrogen peroxide, carbamide peroxide, sodium percarbonate, sodium perborate — claim 4), a peroxide stabilizer, a coating-forming agent expressly including polyvinylpyrrolidone and a PVP–hydrogen-peroxide homopolymer, a coating-forming aid, a wetting agent (glycerin, PEG, propylene glycol, sorbitol), a plasticizer and a sweetener. The patent's stated object is that the patch is "flexibly attached to teeth in accordance with the teeth shape." The Korean family member (https://patents.google.com/patent/KR100507675B1/ko) reports that the jelly patch has tack "about that of a water-soluble poultice," dissolves more slowly than a gel-type strip or dry patch, and keeps peroxide in contact with the teeth longer. (https://patents.google.com/patent/US20040241110; https://patentimages.storage.googleapis.com/5d/a8/dd/4556e1574496c0/US20040241110A1.pdf)
• US 2009/0130624 A1 (Sun, "Methods and kits for making flexible dental guards"), pub. 2009-05-21. Cited on the face of the '444. It post-dates the 2006 priority date, so it is only available art if some claim is not entitled to the 2006 benefit date (see § 5).

Group II — Peroxide whitening gel on a strip, stable in thin-layer storage

• US 6,582,708 B1 (P&G, Sagel et al., 2003-06-24). "A product comprising tooth whitening substance which comprises a high concentration of water, a peroxide, a gelling agent, and carrier materials. The tooth whitening substance will remain stable when stored as a thin layer," plus methods of making "a stable thin layer of tooth whitening substance on a strip of material." (https://worldwide.espacenet.com/publicationDetails/biblio?CC=US&NR=[6582708B1](/patent/6582708B1))
• P&G strip family — US 5,879,691; US 5,894,017; US 6,045,811; US 6,136,297; WO 98/55044 A1; US 2002/0018754 A1 ("Shapes for tooth whitening strips"). Strip of material with low flexural stiffness / permanently deformable, conforming to teeth and adjoining soft tissue under <250,000 Pa, oral-care substance providing adhesive attachment and having extrusion resistance. (Examiner's claim chart reproduced at https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1462657](/patent/1462657)/download-documents and https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1462819](/patent/1462819)/download-documents)
• US 6,514,483 B2 (Colgate, strip for whitening tooth surfaces); US 6,500,408 B2 (JC Technologies, enamel-safe tooth bleach); US 6,685,923 B2 (Dentsply, tooth whitening material); US 8,652,446 B2 / ES 2,320,321 T3 (LG Household & Healthcare, patches and apparatus for whitening teeth).

Group III — Hydrogel whitening compositions built on poly(N-vinyl lactam) (PVP-class) polymers

• US 8,840,918 B2 and US 8,206,738 B2 (A.V. Topchiev Institute / Corium). A water-swellable, water-insoluble polymer + "a blend of a hydrophilic polymer and a complementary oligomer capable of hydrogen bonding to the hydrophilic polymer" + a whitening agent, preferably peroxide. The hydrophilic polymer is expressly a poly(N-vinyl lactam) = PVP-class; the compositions may be made as a dry film/strip, self-adhesive, tack-controlled, translucent, and the stated object is to avoid needing a tray, including "non-solid (e.g., liquid or gel) and which forms a film when dry." (https://www.freepatentsonline.com/[8840918](/patent/8840918).html; https://patentimages.storage.googleapis.com/59/3c/b5/f3502a819ea9e8/EP2279725A3.pdf; https://patents.justia.com/patent/20170071833)

Group IV — Solid / gelatinous, non-fluid, tray- or strip-borne treatment compositions (Ultradent and others)

• US 7,056,118 B2 and US 7,059,857 B2 (Ultradent, 2006-06-06 / 2006-06-13; applications filed 2003-05-27) — compositions and devices having a tray-like configuration; "substantially solid" desensitizing/treatment compositions.
• US 6,860,736 B2 (2005-03-01) — oral treatment devices with a thin flexible barrier layer and an endoskeleton treatment or adhesive composition; US 7,192,280 B2 (2007-03-20; filed 2004-02-19) — bleaching devices with a protective adhesive region; US 6,997,708 B2 / US 7,011,523 B2 — solid adhesive layer with treatment/bleaching gel adjacent thereto; US 7,625,210 B2; US 2007/0298380 A1; and the analogous EP 1 633 273 B1, JP 4805834 B2, BR PI0410762 B1, EA 008520 B1.
• US 2005/0255054 A1 (Philp, 2005-11-17) — tooth whitening using a dissolvable tray or strip.

⚠️ Note: I verified only the titles, dates, assignees and published abstracts of the Group IV items as they appear on the patent page; I did not open each full text. Their disclosures should be confirmed before being relied on in a formal challenge.

Group V — The polymer chemistry: poly(2-oxazoline)s in oxidizing aqueous media

• US 4,144,211 A (Dow Chemical, 1979-03-13) — cited in the family. Discloses complexes of poly-2-oxazoline (and poly-2-oxazine) with halogens/interhalogens/pseudohalogens. The companion Dow specification (https://patentimages.storage.googleapis.com/cf/50/fd/8a1a3bca85d3d9/[US4186191](/patent/US4186191).pdf) states that the R groups may be hydrogen, phenyl or lower C1–C4 alkyl, "with 2-ethyl-2-oxazoline as the monomer of choice," with molecular weights "up to about 500,000"; that the complexes are water-soluble; and that "aqueous solutions of the complexes comprising I₂ or Br₂ are of particular interest because of their utility as sanitizing agents and oxidative properties."
• JPH 06239912 A (Nippon Shokubai, 1994) — production of polymer (oxazoline polymerization), also family-cited.
• AU 2002314772 A1 (Biofx Laboratories, 2002-11-18) — "Stabilizing peroxides with stannous halides": evidence that stabilizing peroxide in oral/antiseptic formulations was an active, recognized problem in the art.
• US 6,320,360 B1 (3M) — medication retention assembly for an oral delivery tray; US 6,115,629 A / US 6,315,566 B1 — dental/hydrogel materials generally.

Post-2006 items (US 2009/0130624; WO 2015/053808 A1 and CN 111658213 B — Ultradent wax-based compositions; US 2010/0028829 A1; US 2016/0175207 A1 — Jensen, whitening film with tripolyphosphate salts; US 2023/0210731 A1 — Cao Group, reduction-resistant hydrogel thickeners; the Microban/consumer-goods art) are not prior art against claims entitled to the 2006-02-08 date and are relevant only in the priority-failure scenario.

3. The § 103 combination that renders claims 1–6 obvious

Ground 1 (primary): Lee + Dow, optionally + P&G '708

Claim 2: the added six-month, room-temperature, in-package and post-removal gel stability is met or rendered obvious by P&G '708 ("will remain stable when stored as a thin layer"), by Corium's water-swellable hydrogels that are stored dry and rehydrate in the mouth, and by Lee's own comparative showing of sustained peroxide delivery from the jelly layer.

Claims 3–6: claim 3 removes the backing and the peroxide requirement; the remaining combination (whitening agent + PVP or PEtOx, in a planar gelatinous strip) is disclosed/obvious from Lee alone (PVP branch) or Lee + Dow (PEtOx branch). Claim 6's solvent is met by Lee's water/ethanol. Claim 5's peroxide is met by Lee's claim 4.

Ground 2 (strips): P&G 5,879,691 / 5,894,017 / 6,045,811 / 6,136,297 / 6,582,708 + Dow, optionally + Corium

P&G supplies the flexible, permanently deformable planar strip, the adhesive, conformable oral-care substance with extrusion resistance, and the thin-layer storage stability; Corium supplies the PVP-class hydrophilic polymer + peroxide in a dry film that becomes adhesive in the mouth; Dow supplies PEtOx as a water-soluble, oxidant-compatible thickener. Result: claims 1–6 obvious.

Ground 3 (hydrogel): Corium 8,840,918 / 8,206,738 + P&G or Lee + Dow

Corium's composition is a self-adhesive, tack-controlled whitening film built on a poly(N-vinyl lactam) (PVP) hydrophilic phase — i.e., the claim-1/3 Markush's second species — and expressly contemplates both solid and "non-solid (gel) which forms a film when dry" forms. Substituting the isomeric/chemically cognate poly(2-ethyl-2-oxazoline) at Dow's teaching yields the PEtOx branch.

Ground 4 (non-fluid, "without cracking"): Ultradent Group IV + Dow/Corium

The Ultradent family supplies substantially solid, non-fluid, gelatinous treatment/bleaching compositions in tray-like or strip-borne form that conform to the dental arch, addressing precisely the "cracking and breaking" and "messy fluid gel" problems the '444 recites. Because "non-fluid," "gelatinous" and "without cracking or breaking" are functional/result-oriented limitations, and their presence in the prior-art compositions is an inherent-property question, the burden shifts to the patentee under In re Best / In re Swinehart to show that the prior compositions lack the recited character.

4. Why a POSITA would have combined these references (motivation)

1. The problem was known and shared. The '444's own background states that "CARBOPOL does not hold up to pure hydrogen peroxide for even short amounts of time," and that "there are very few thickeners that can withstand a peroxide environment." Lee (peroxide stabilizers), P&G '708 (thin-layer stability) and Biofx (stabilizing peroxides) confirm the field was actively working on exactly this problem. KSR makes it enough that the combination addresses a known problem with a finite number of identified, predictable solutions.
2. Same class, same function, same physical form. PEtOx and PVP are both nonionic, water-soluble, hygroscopic, tertiary-amide N-containing polymers that form viscous aqueous gels and coherent films. Poly(2-ethyl-2-oxazoline) is the ring-opened isomer of polyvinylpyrrolidone (2-ethyl-2-oxazoline → ring-opened N-propionyl repeat unit vs. N-vinylpyrrolidone polymer). Structural and property identity of this degree supports the "obvious to try" and structural-similarity lines of authority.
3. Dow supplies the missing expectation of success. Dow teaches that 2-ethyl-2-oxazoline polymers up to 500,000 MW (the very grades the '444 uses) are water-soluble and form stable complexes in aqueous oxidizing systems useful for their "oxidative properties." A POSITA reading Dow would expect PEtOx to tolerate an oxidizing aqueous environment rather than being consumed by it — the precise property the '444 calls "surprising."
4. The polymer was a commercial, catalogued material. The '444 itself concedes PEtOx is "commercially available in 50,000, 200,000 and 500,000 M.W." and elsewhere that PVP "may be used in this invention with good results." That is an admission that the claimed Markush is a routine formulator's choice among known water-soluble polymers.
5. Routine optimization. Lee's film, P&G's strip, Corium's film and Ultradent's tray-like bodies are all "a flexible backing + a coherent peroxide-containing layer." Selecting a different known gel former for that layer is routine formulation work with an expectation of predictable adhesive/elastic properties.
6. No teaching away. Dow's complexation chemistry teaches reversible interaction with oxidizing species (indeed, marketed as sanitizing/oxidative), not destruction of the polymer. Nothing in the record suggests the art disparaged polyoxazolines for oral use.

5. Counterarguments the patentee can make, and their weakness

• "Unexpected results." The '444 asserts "six months" stability at 30% H₂O₂ and calls PEtOx "superior … to CARBOPOL, silica, PVP, and polyethylene glycols." But the specification contains no comparative data, no test protocol, no control, and no data at all for PEtOx vs. PVP in the same formulation. Under KSR, a difference in degree of performance is not enough; the patentee would need a comparative showing of a difference in kind.
• "PVP was known to be inferior / the invention selects PEtOx." Undermined by the specification's own statement that PVP "may be used in this invention with good results," and by the claims themselves reciting PVP. There is no teaching away from PVP; rather, PVP is described as a working alternative.
• "The prior art compositions crack or dry out." This is the patentee's best argument, but it is a factual, inherent-property dispute. The '444 claims the result, not the mechanism (hygroscopicity, solvent compatibility, elasticity). If P&G '708 or Corium's film exhibits the recited behaviour, the claims are anticipated; if not, the difference is at most a change to a known property of a known material.
• Non-analogous art. Difficult: Dow is polymer/oxidation chemistry applied to the same aqueous oxidizing-media problem; Lee, P&G, Corium and Ultradent are all the same field of endeavor (oral whitening devices).
• Secondary considerations. The record as presented on the patent page shows no evidence of unexpected results, commercial success nexus, copying, or industry praise. Post-grant litigation (below) may supply evidence, but none is in the intrinsic record.

Independent (non-§ 103) theories worth flagging separately: (i) § 112 indefiniteness/§ 112(a) as to the coined term "non-coalescent", defined only by the specification's beaker-test definition of "fluid" and "gelatinous," and (ii) the claim term "polyethyloxazoline" versus the specification's "Poly(2-ethyl-2-Oxazoline)" — a POSITA would read the claim term as at least covering the 2-ethyl-2-oxazoline homopolymer, and possibly a broader poly(alkyloxazoline) genus (which Dow also describes).

6. Priority-date risk that materially enlarges the prior art

The '444 is a continuation of 17/557,560 (filed 2021-12-21) → 16/784,582 (2020-02-07) → 15/627,906 (2017-06-20) → 14/710,416 (2015-05-12) → 12/329,582 → CIP of 11/307,463 (2006-02-08). Note the record itself is inconsistent on the 12/329,582 filing date: the specification says "filed Dec. 12, 2008," while the Family table and the Google data say 2008-12-06. I take the identifiers/dates literally as they appear and flag the discrepancy rather than reconciling it.

Consequence: the operative priority date for any given claim is the filing date of the earliest application in that chain that supports that claim. If "non-coalescent," the dried-gelatinous strip format, or the claimed six-month in-package stability is not supported by 11/307,463 (2006) — or even by 12/329,582 (2008) — the effective date shifts and additional art becomes available, including US 2009/0130624 A1 (Sun, flexible dental guards), which is already cited on the face of the '444. Note also that the reported expiration (2026-02-08) shows the Office measured term from 2006-02-08; that is a term calculation under § 120 and does not, by itself, prove written-description support for the claims.

7. Bottom line and procedural posture

• Claims 1, 3, 4, 6 (PVP branch): very strong § 102/§ 103 exposure to Lee (US 2004/0241110 A1) alone, which is § 102(b) art (published 2004-12-02, more than one year before 2006-02-08) and expressly discloses a flexible film patch with a jelly peroxide adhesive containing PVP, water/ethanol solvent and humectant — with P&G '708 and Corium as corroborating secondary references.
• Claims 1–6 (PEtOx branch): strong § 103 exposure to Lee + US 4,144,211 A (Dow) as the primary combination, with P&G '708 and/or Corium 8,840,918 supplying the strip/hydrogel/thin-layer-stability teachings. The motivation is supplied by the shared polymer class and by Dow's express disclosure of 2-ethyl-2-oxazoline polymers in aqueous oxidizing (sanitizing) systems.
• Claim 2's storage-stability limitation does not save the claim: P&G '708 expressly claims a peroxide whitening substance "stable when stored as a thin layer," and In re Best shifts to the patentee the burden of showing the prior compositions lack the recited gel character.
• The strongest defensive posture for the patentee is an unexpected-results case with real comparative data (PEtOx vs. PVP, carbomer, silica and PEG at 30% H₂O₂ over six months), which is absent from the intrinsic record.

Status flags: The page reports the patent expired as of 2026-02-08 ("Expired – Lifetime"), i.e., roughly two months before the current date, which bears on the practical value of any invalidity challenge. The page also records seven US litigation matters across N.D. Illinois (1:24-cv-04903; 1:24-cv-05129), D. Utah (2:24-cv-00498; 2:24-cv-00175), C.D. California (8:25-cv-02074) and D. Delaware (1:25-cv-01430). Prosecution shows a non-final action (2022-12-20), a final rejection (2023-04-11), a response after final (2023-08-08) and issue fee payment (2023-09-08); the page does not reproduce the grounds of rejection or the amendment, so I cannot state what was actually distinguished over Lee.

Confidence/limits: I verified the full text and dates of Lee (US 2004/0241110 A1), Dow (US 4,144,211 A and its companion US 4,186,191), P&G US 6,582,708 and the Corium 8,840,918 family abstract/claims. For the Ultradent Group IV references and US 2009/0130624 A1 (Sun), I relied on titles, dates and assignees as listed on the patent page and did not open the full texts — those should be verified before filing. A search also surfaced a snippet from an unidentified third-party patent describing "a dental bleaching composition compris[ing] a dental bleaching agent and a polyvinylpyrrolidone thickening agent… in combination with a moisture-resistant barrier layer such as a dental tray or a flexible strip of material" ("Patents Examined by Lezah Roberts," https://companyprofiles.justatic.com/examiner/lezah-roberts?page=11); I could not confirm its publication number and therefore do not rely on it, but it is a lead worth chasing.