DCT

1:26-cv-11795

CAO Group Inc v. Hismile Pty Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:26-cv-11795, N.D. Ill., 09/25/2026
  • Venue Allegations: Venue is alleged to be proper because the Defendant is a foreign entity, which may be sued in any judicial district, and because Defendant allegedly committed acts of infringement in the district by selling accused products through retail stores and online storefronts.
  • Core Dispute: Plaintiff alleges that Defendant’s teeth whitening strips infringe a patent related to conformable, gelatinous dental compositions.
  • Technical Context: The technology concerns chemical compositions for consumer teeth whitening strips, aiming to provide a product that is stable, effective, mess-free, and conforms well to a user's teeth.
  • Key Procedural History: The asserted patent claims priority to an application filed in 2006 and expired in February 2026. This lawsuit, filed in September 2026 after the patent's expiration, seeks monetary damages for past infringement that occurred during the patent's term.

Case Timeline

Date Event
2006-02-08 '444 Patent Priority Date
2010-00-00 Plaintiff launches its Sheer White!® Teeth Whitening Strips
2023-11-28 U.S. Patent No. 11,826,444 Issues
2024-08-30 Alleged infringing sale of Accused Product into the district
2026-02-08 '444 Patent expires
2026-09-25 Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 11,826,444 - "Peroxide Gel Compositions"

The Invention Explained

  • Problem Addressed: The patent describes several problems with prior art teeth whitening methods Compl. ¶13 Custom-molded trays were cumbersome to create, while generic trays and strips using fluidic gels were messy, did not adhere well, and allowed saliva to wash away the active ingredients, reducing effectiveness Compl. ¶13 ’444 Patent, col. 2:27-3:54 More rigid compositions tended to crack or break when flexed to fit a user’s teeth Compl. ¶14 ’444 Patent, col. 3:55-4:24
  • The Patented Solution: The patent discloses a formable dental whitening device comprising a flexible backing strip carrying a “gelatinous, non-coalescent, visco-elastic” composition ’444 Patent, abstract This composition, which uses specific thickeners such as polyvinylpyrrolidone (PVP), is designed to be stable, highly viscous, and adhere to the backing strip ’444 Patent, col. 6:35-50 When applied, the strip is intended to conform to a user's dental arch without cracking, providing better contact and a less messy application ’444 Patent, col. 8:22-30 The patent likens the composition's flexibility and consistency to "gummi worms" Compl. ¶17 ’444 Patent, col. 8:26-28
  • Technical Importance: This approach sought to enable the creation of shelf-stable, consumer-friendly whitening strips that could carry higher concentrations of active ingredients and provide a better fit and user experience than previous technologies Compl. ¶15 ’444 Patent, col. 6:35-42

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 3, and dependent claim 5 Compl. ¶51
  • Independent Claim 1 requires:
    • A flexible, planar strip of backing material with two flat sides.
    • A “gelatinous, non-coalescent, visco-elastic” dental composition on the backing.
    • The composition must comprise a tooth whitening agent, a solvent, and a thickening agent selected from polyethyloxazoline or polyvinylpyrrolidone (PVP).
    • The device must be able to flex and conform to a user’s dental arch without cracking or breaking when adhered.
  • The complaint notes that it reserves the right to assert additional claims Compl. ¶60

III. The Accused Instrumentality

Product Identification

  • The complaint identifies Defendant’s “PAP+ Strips” as the Accused Products Compl. ¶33

Functionality and Market Context

  • The Accused Products are sold as “convenient, mess-free teeth whitening strips” Compl. ¶40 The complaint includes a photograph of the product packaging, which lists the ingredients, as Exhibit C Compl. ¶33 This ingredient list is alleged to include "PVP" (polyvinylpyrrolidone), one of the thickening agents recited in the patent, and "Phthalimidoperoxycaproic Acid (PAP)," which the complaint identifies as the tooth whitening agent Compl. ¶39 Compl. ¶56 Instructions direct the user to peel a strip, apply the "sticky side" to the teeth, and press and fold it to secure it for a 30-minute treatment Compl. ¶40 The complaint also references a screenshot of Defendant’s website, provided as Exhibit E, which describes PAP as a "scientifically proven teeth whitening ingredient" that "oxidises tooth stains" Compl. ¶41

IV. Analysis of Infringement Allegations

'444 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a strip of backing material, wherein the strip of backing material is flexible and planar such that the strip of backing material has two flat sides Each Accused Product includes upper and lower strips made of a thin, flat, flexible film backing that carries the whitening composition. ¶54 col. 8:10-13
a gelatinous, non-coalescent, visco-elastic dental composition conjoined to at least a portion of one of the flat sides of the strip of backing material The dental composition is alleged to be gelatinous, non-coalescent, and visco-elastic, having properties between a solid and a fluid, and is marketed as "mess-free." ¶55 col. 5:54-6:8
the dental composition being comprised of a tooth whitening agent, a solvent, and a thickening agent selected from the set of thickening agents consisting of polyethyloxazoline and polyvinylpyrrolidone (PVP) The product packaging allegedly discloses that the composition contains a whitening agent (PAP), a solvent (Water/Aqua), and a recited thickening agent (PVP). ¶56 col. 10:3-11
wherein when adhered to a user's dental arch both the dental composition and the backing material flex and conform to the user's dental arch without cracking or breaking The complaint alleges that for the product to be used as instructed—pressed and folded over teeth—it must necessarily flex and conform to the dental arch without cracking. ¶57 col. 8:22-30
  • Identified Points of Contention:
    • Scope Questions: A central question may be the scope of the term "a tooth whitening agent." The patent is titled "Peroxide Gel Compositions," but Claim 1 is not explicitly limited to peroxides. Defendant markets its product as "Peroxide Free," using PAP as the active ingredient Compl. ¶58 The complaint argues that PAP is a type of peroxide and, alternatively, that the claim is broad enough to cover non-peroxide agents, pointing to specification language and the doctrine of claim differentiation Compl. ¶19 Compl. ¶58
    • Technical Questions: A key factual question may be whether the accused PAP+ Strips' composition meets the specific definition of "gelatinous, non-coalescent, visco-elastic" provided in the patent. The patent defines these terms with specific physical properties, such as the material's behavior over 10 minutes under certain conditions ’444 Patent, col. 6:1-8 The complaint alleges this limitation is met "on information and belief," citing the product's "mess-free" marketing and its ability to be pressed onto teeth Compl. ¶55 The actual physical properties of the accused composition will likely be a subject of discovery and expert analysis.

V. Key Claim Terms for Construction

  • The Term: "a tooth whitening agent"

    • Context and Importance: This term's construction is critical because Defendant's product uses PAP and is marketed as "Peroxide Free," while the patent is titled "Peroxide Gel Compositions." The infringement analysis hinges on whether PAP falls within the scope of this term as used in the patent.
    • Intrinsic Evidence for a Broader Interpretation: The plain language of independent claims 1 and 3 requires only "a tooth whitening agent" without limitation to peroxide Compl. ¶19 The specification states that "other active ingredients may be added to the composition for more desired effects, with or without peroxide" ’444 Patent, col. 10:3-5 Furthermore, dependent claim 5 recites "the tooth whitening agent being a peroxide," which suggests by claim differentiation that the independent claim from which it depends is not limited to peroxides Compl. ¶19
    • Intrinsic Evidence for a Narrower Interpretation: The patent's title, abstract, and much of the detailed description focus on peroxide-based compositions, such as hydrogen peroxide and carbamide peroxide ’444 Patent, abstract ’444 Patent, col. 9:1-10:65 A defendant might argue this context limits the invention's scope to conventional peroxides, excluding PAP.

  • The Term: "gelatinous, non-coalescent, visco-elastic"

    • Context and Importance: This compound term is a cornerstone of the invention, distinguishing it from prior art fluids and brittle solids. Practitioners may focus on this term because the patentee acted as their own lexicographer, providing a highly specific, technical definition that may not be met by a product that is merely "gel-like" in a colloquial sense.
    • Intrinsic Evidence for a Broader Interpretation: The specification uses an analogy, stating the composition has a "flexibility and consistency similar to the popular confection known as gummi worms" ’444 Patent, col. 8:26-28 This could be argued to support a more functional interpretation based on feel and behavior rather than strict testable parameters.
    • Intrinsic Evidence for a Narrower Interpretation: The patent explicitly defines "gelatinous" by reference to definitions for "solid" and "fluid," stating that the gelatinous compound "will have some degree of flex and deformation ... but will not coalesce so that a specific sample or portions thereof are still determinable" after 10 minutes under specified conditions ’444 Patent, col. 5:54-6:8 This explicit definition provides a precise, testable standard that will likely be central to claim construction.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that Defendant "infringed directly and/or indirectly" Compl. ¶51 It alleges inducement may be supported by the instructions on the accused product's packaging and website, which allegedly direct users to apply the strips in an infringing manner Compl. ¶40 Compl. ¶41 Compl. ¶54
  • Willful Infringement: The complaint alleges that Defendant knew of the '444 Patent, or was willfully blind to it, no later than its issue date of November 28, 2023 Compl. ¶45 It is alleged that Defendant’s continued sales after this date, including a documented sale in August 2024, constitute knowing and willful infringement warranting enhanced damages Compl. ¶45-46 Compl. ¶63

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of definitional scope: can the term "a tooth whitening agent", from a patent titled and heavily focused on "peroxide," be construed to cover the Phthalimidoperoxycaproic Acid (PAP) used in Defendant's product, which is marketed as "peroxide-free"? Resolution will depend on claim construction, weighing the plain language and claim differentiation against the specification's context.

  • A second key issue will be one of technical evidence: does the composition of the accused PAP+ Strips meet the patent’s highly specific and technical definition of being "gelatinous, non-coalescent, and visco-elastic"? This question may turn on the results of expert testing and analysis comparing the physical properties of the accused product against the precise parameters laid out in the patent's specification.