DCT
1:17-cv-01730
3M Co v. Kerr Corp
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: 3M Company and 3M Innovative Properties Company (Delaware)
- Defendant: Kerr Corporation (Delaware)
- Plaintiff’s Counsel: Richards, Layton & Finger, P.A.; Faegre Baker Daniels LLP
- Case Identification: 1:17-cv-01730, D. Del., 12/01/2017
- Venue Allegations: Venue is alleged to be proper in the District of Delaware because the Defendant, Kerr Corporation, is incorporated in the State of Delaware and therefore "resides" in the district.
- Core Dispute: Plaintiff alleges that Defendant’s dental composite products infringe a patent related to a specific combination of nanoparticle fillers used in dental restorative materials.
- Technical Context: The technology concerns dental composites, materials used for fillings and restorations, where performance depends on a balance of strength, durability, and aesthetic properties like polishability and luster.
- Key Procedural History: The complaint notes that the parties engaged in prior patent litigation beginning in 2006, which resulted in a settlement and a license agreement concerning a different 3M patent. The complaint also alleges that Defendant had pre-suit knowledge of the patent-in-suit because it was listed as a cited reference on one of Defendant's own patents, a fact which may be relevant to the allegation of willful infringement.
Case Timeline
| Date | Event |
|---|---|
| 1999-10-28 | '693 Patent Priority Date |
| 2003-06-03 | '693 Patent Issue Date |
| 2015-04-15 | Accused Product SonicFill 2 Launch Date |
| 2016-11-28 | Accused Product Harmonize Launch Date |
| 2017-12-01 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
- Patent Identification: U.S. Patent No. 6,572,693, "AESTHETIC DENTAL MATERIALS," issued June 3, 2003.
The Invention Explained
- Problem Addressed: The patent's background section describes a challenge in formulating dental materials: fillers with large particles provide mechanical strength but result in poor aesthetics and a dull surface after wear, while fillers with very small particles may offer better aesthetics but lack sufficient strength for many applications (’693 Patent, col. 1:21-48).
- The Patented Solution: The invention claims to solve this problem by using a filler with a "unique combination" of two distinct components: (i) larger, porous "clusters" of nano-sized particles that provide strength, and (ii) separate, "non-agglomerated" nano-sized particles that fill the interstitial spaces between the clusters (’693 Patent, Abstract; col. 2:25-34). This dual-component system is described as creating a synergistic effect, yielding a material with both high strength and excellent aesthetic qualities like polishability and luster (’693 Patent, col. 2:27-34).
- Technical Importance: This approach sought to create a "universal" dental composite suitable for both high-stress posterior restorations and aesthetic anterior restorations, a significant goal in restorative dentistry (’693 Patent, col. 1:21-34).
Key Claims at a Glance
- The complaint asserts infringement of one or more claims, including at least independent claim 1 (Compl. ¶24).
- The essential elements of independent claim 1 are:
- A material comprising: (a) a hardenable resin; and
- (b) a filler comprising
- (i) clusters of nano-sized particles, said clusters comprising non-heavy metal oxide particles and heavy metal oxides and being not fully densified and
- (ii) non-agglomerated nano-sized particles selected from the group consisting of non-heavy metal oxide particles, heavy metal oxide particles, and combinations thereof,
- wherein said material is a dental material.
- The complaint reserves the right to assert other claims, which may include dependent claims (Compl. ¶24).
III. The Accused Instrumentality
Product Identification
- Kerr’s SonicFill 2 Composite and Harmonize Universal Composite (Compl. ¶16).
Functionality and Market Context
- The complaint describes the accused products as resin-based, light-cured dental restoratives (Compl. ¶18). The Harmonize product is alleged to contain a "nanoparticle filler network" and a "reinforced filler structure" in which "very small spherical Silica and Zirconia particles are linked together and fused in a reinforced structure" (Compl. ¶19, ¶21). The SonicFill 2 product is alleged to contain a "new filler system" including "nano-scale zirconium oxide and silica oxide particles" (Compl. ¶17). An image from the defendant's website for the Harmonize product depicts this "Reinforced filler structure" (Compl. ¶21).
- The complaint alleges that these products compete directly with Plaintiff's Filtek™ Supreme line of products (Compl. ¶5, ¶10, ¶35).
IV. Analysis of Infringement Allegations
U.S. Patent No. 6,572,693 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A material comprising: (a) a hardenable resin; | The accused SonicFill 2 and Harmonize products are described as "light-cured, low-shrink, resin-based, dental restorative" materials, which are alleged to contain a hardenable resin (Compl. ¶18, ¶27). | ¶27 | col. 11:15-24 |
| and (b) a filler comprising (i) clusters of nano-sized particles, said clusters comprising non-heavy metal oxide particles and heavy metal oxides and being not fully densified | The accused products are alleged to contain fillers with "clusters of nano-sized particles" comprising silica (a non-heavy metal oxide) and zirconia (a heavy metal oxide), where the clusters are "not fully densified." This is supported by an image of Harmonize's "reinforced filler structure" (Compl. ¶21). | ¶21, ¶28 | col. 4:21-45 |
| and (ii) non-agglomerated nano-sized particles selected from the group consisting of non-heavy metal oxide particles, heavy metal oxide particles, and combinations thereof, | The fillers in the accused products are alleged to "also include at least non-agglomerated nano-sized particles of silica and/or zirconia" in addition to the clusters (Compl. ¶29). | ¶29 | col. 7:31-35 |
| wherein said material is a dental material. | Both SonicFill 2 and Harmonize are marketed and sold as dental restorative materials (Compl. ¶18, ¶19, ¶27). | ¶27 | col. 3:28-37 |
- Identified Points of Contention:
- Scope Questions: A central question may be whether the term "clusters of nano-sized particles", as defined in the patent, reads on the accused products' "reinforced filler structure" (Compl. ¶21). The analysis will turn on whether the properties of the accused structure—such as its method of formation, porosity, and degree of particle association—fall within the scope of the patent’s specific definition of a "cluster."
- Technical Questions: The complaint alleges the accused products contain both "clusters" and separate "non-agglomerated nano-sized particles" (Compl. ¶26, ¶28-29). A key evidentiary question will be whether discovery and expert analysis can demonstrate the presence of these two distinct filler components as required by the claim, rather than just one type of composite structure. Another technical question is whether the accused "clusters" are "not fully densified" as the patent requires, a property defined by specific analytical techniques like the BET method (’693 Patent, col. 4:45-51). The complaint alleges this but does not provide technical data to support it.
V. Key Claim Terms for Construction
The Term: "clusters of nano-sized particles"
- Context and Importance: This term defines the primary structural component of the claimed filler. The infringement case hinges on whether Defendant’s "reinforced filler structure" (Compl. ¶21) meets this definition.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification states that the term ""cluster" refers to the nature of the association among the...particles" which are associated by "relatively weak intermolecular forces that cause them to clump together, i.e., to aggregate, even when dispersed in a hardenable resin" (’693 Patent, col. 4:21-27). This could support a broad reading covering various forms of particle aggregation.
- Evidence for a Narrower Interpretation: The patent describes a specific multi-step process for creating the clusters, including mixing precursor sols, spray drying, and calcining, which results in a "substantially amorphous" structure that is "not fully densified" (’693 Patent, col. 6:10-68; col. 4:21-45). A party may argue the term should be limited to structures possessing the specific properties imparted by such a process.
The Term: "not fully densified"
- Context and Importance: This limitation distinguishes the claimed "clusters" from conventional, solid filler particles. Plaintiff must prove that Defendant's structures possess this characteristic.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent states the phrase describes a particle that is not "near theoretical density, having substantially no open porosity" (’693 Patent, col. 4:42-45). This is a qualitative description that could be interpreted broadly.
- Evidence for a Narrower Interpretation: The patent explicitly references the Brunauer-Emmet-Tell (BET) method using nitrogen adsorption to determine surface area as a way to detect porosity, giving "an indication of porosity" (’693 Patent, col. 4:45-51). A party could argue that the term requires a measurable level of porosity detectable by this specific, quantitative analytical technique.
VI. Other Allegations
- Willful Infringement: The complaint alleges that Defendant’s infringement was and is willful (Compl. ¶33-37). The factual basis for this allegation includes the assertion that Defendant had pre-suit knowledge of the ’693 Patent because it was cited as a reference on one of Defendant's own assigned patents (U.S. Patent No. 6,890,968) (Compl. ¶34). The complaint also alleges knowledge based on Defendant’s familiarity with Plaintiff’s commercial products, which are marked with the ’693 Patent number (Compl. ¶35).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of structural definition: can the term "clusters of nano-sized particles... being not fully densified," which is described in the patent as being formed through a specific chemical process, be construed to cover the "reinforced filler structure" in the accused dental composites? The outcome will depend on whether the physical and chemical properties of the accused structures meet the specific limitations described in the patent's specification.
- A second key issue will be one of compositional evidence: does the accused filler system contain two distinct populations of particles—the larger "clusters" and the separate "non-agglomerated" nanoparticles—as required by Claim 1? The plaintiff will bear the burden of proving, likely through materials science and microscopy evidence, that both claimed components are present in the accused products.