Neuralpulse Ltd. v. Water Pik, Inc: Water Dental Flosser Patent Suit Dismissed
Neuralpulse Ltd. and LuminaThrive LLC sued Water Pik, Inc in the Colorado District Court asserting US9642677B2 covering water dental flosser technology. The plaintiffs voluntarily dismissed the case without prejudice just 20 days after filing — one of the shortest litigation windows in district court patent practice.
A 20-day patent suit against a leading oral care brand — what happened?
On 10 May 2025, Neuralpulse Ltd. and LuminaThrive LLC filed a patent infringement complaint against Water Pik, Inc in the U.S. District Court for the District of Colorado before Judge N. Reid Neureiter. The suit centred on US9642677B2 — a patent covering water dental flosser technology — and targeted Water Pik’s oral irrigation product line. Plaintiff counsel was provided by Glacier Law LLP, with attorneys Tao Liu and Wei Wang on record.
Just 20 days later, on 30 May 2025, the plaintiffs invoked Federal Rule of Civil Procedure 41(a)(1)(A)(i) to voluntarily dismiss the action against Water Pik, Inc without prejudice. This procedural mechanism allows a plaintiff to withdraw a complaint as of right before the defendant has served an answer or a motion for summary judgment — meaning the case closed before Water Pik formally responded. No merits determination was reached, and no costs were awarded.
The extreme brevity of this litigation — 20 days from filing to dismissal — is commercially significant. Voluntary dismissals without prejudice at this early stage typically suggest settlement discussions, a reassessment of claim mapping, or a strategic repositioning rather than an abandonment of the underlying IP rights. The public record does not disclose whether any agreement was reached between the parties, leaving Water Pik’s freedom-to-operate position relative to US9642677B2 formally unresolved.
Filing to Voluntary dismissal in 20 days
Case resolved in 20 days — significantly below the district court median of 2–3 years
Voluntarily dismissed: what the Rule 41 exit means for both parties
Rule 41(a)(1)(A)(i): plaintiff’s unilateral exit before any answer
Fed. R. Civ. P. 41(a)(1)(A)(i) permits a plaintiff to dismiss a complaint without a court order — and without prejudice — before the defendant serves an answer or a motion for summary judgment. Because Water Pik had not yet formally responded, Neuralpulse exercised this right unilaterally. No judicial ruling on the merits was required or issued.
No merits adjudicationWithout prejudice — but what does the public record actually confirm?
The verdict text explicitly states dismissal ‘without prejudice’, meaning Neuralpulse and LuminaThrive retain the right to refile claims based on US9642677B2 against Water Pik in the future. Unlike a dismissal with prejudice, the underlying patent claims are not extinguished. Practitioners should note, however, that the record does not disclose whether a confidential settlement or covenant-not-to-sue was negotiated alongside the dismissal.
Refiling right preservedNeuralpulse preserves its enforcement options on US9642677B2
By dismissing without prejudice, Neuralpulse and LuminaThrive keep US9642677B2 available as an enforcement tool. No claim construction, invalidity ruling, or non-infringement finding was entered — the patent emerges from this litigation with its presumption of validity fully intact. Whether this reflects a negotiated resolution or a tactical retreat, plaintiffs retain full optionality.
Patent validity untestedWater Pik faces unresolved FTO risk in oral irrigation technology
For Water Pik and competitors in the oral irrigation and water flosser market, this outcome provides no formal clearance. US9642677B2 was never invalidated or found non-infringed. The 20-day window suggests the parties may have reached an informal arrangement, but absent a public covenant or licence disclosure, prudent product teams should treat this patent as an active risk requiring independent FTO analysis.
FTO risk unresolvedFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Neuralpulse Ltd. | Company | Oral care technology IP holder — asserting US9642677B2 for water dental flosser innovationsSearch in Eureka ↗ |
| Defendant | Water Pik, Inc | Company | Water Pik, Inc — leading manufacturer of water flossers and oral irrigation devicesSearch in Eureka ↗ |
| Plaintiff counsel | Tao Liu | Attorney | Counsel for Neuralpulse Ltd.Search in Eureka ↗ |
| Plaintiff counsel | Wei Wang | Attorney | Counsel for Neuralpulse Ltd.Search in Eureka ↗ |
| Plaintiff law firm | Glacier Law LLP | Law Firm | Representing Neuralpulse Ltd.Search in Eureka ↗ |
| Presiding judge | Judge N. Reid Neureiter | Judge | Colorado District CourtSearch in Eureka ↗ |
Official order — verbatim text
The dismissal notice invokes Rule 41(a)(1)(A)(i), which operates as of right — no judicial approval was required or sought. The explicit ‘without prejudice’ language is controlling: Water Pik receives no res judicata protection, and Neuralpulse retains the right to reassert the same claims under US9642677B2. Because no answer was filed, no invalidity counterclaims were preserved by Water Pik. The record is silent on any accompanying commercial terms.
US9642677B2 — Water Dental Flosser Technology
US9642677B2, filed under application number US13/831401, protects innovations in water dental flosser technology — devices that deliver pressurised water streams for interdental cleaning and oral irrigation. The patent sits at the intersection of oral health device engineering and consumer medical equipment design. Its grant reflects a substantive USPTO examination finding novelty and non-obviousness over the prior art in the oral irrigation field.
Water flossers represent a growing segment of the oral care device market, with Water Pik holding a dominant commercial position. A patent covering core water flosser architecture carries meaningful competitive weight: if the claims are broad, they could capture a significant share of commercially available oral irrigation products. The fact that Neuralpulse chose to assert this patent against the category leader — and retained it intact through dismissal — suggests the rights holder views US9642677B2 as a commercially valuable enforcement asset.
Should your oral irrigation product team run an FTO against US9642677B2?
Any company designing, manufacturing, or distributing water dental flossers or oral irrigation devices in the U.S. market should treat US9642677B2 as an active risk. This litigation produced no invalidity finding, no non-infringement ruling, and no public licence. The patent emerged from a 20-day case with its enforceability fully intact and may be reasserted at any time. R&D and product teams planning new oral care device launches should commission independent FTO analysis before entering or expanding in this product category.
PatSnap Eureka’s FTO Search Agent can map your product’s technical features against the independent claims of US9642677B2, identify relevant prior art that could support invalidity arguments, and flag co-pending continuation applications that may extend the patent family’s reach. Eureka’s litigation monitoring layer will also alert you if Neuralpulse refiles against Water Pik or new defendants — giving your team early warning before market exposure increases.
Run a freedom-to-operate analysis on US9642677B2 to assess your product’s exposure
Run FTO in Eureka →Similar oral care device patent suits in U.S. district courts
Explore comparable patent infringement cases involving oral irrigation and water flosser technology filed in U.S. district courts, including the District of Colorado.
What this case signals for oral care device IP enforcement
A sub-30-day patent suit in Colorado rarely reflects weakness — it often signals leverage, negotiation, or strategic repositioning.
Early voluntary dismissals without prejudice are not concessions
A Rule 41(a)(1)(A)(i) dismissal before any defendant response preserves maximum plaintiff optionality. Patent holders who exit this early typically retain enforcement rights in full. IP teams monitoring Water Pik product lines should not interpret this dismissal as a clearance event for US9642677B2.
The 20-day window is consistent with rapid pre-answer negotiation
Cases resolved within three weeks of filing frequently reflect behind-the-scenes discussions: licensing conversations, demand letters already in play, or agreed standstills. The absence of any defendant filing suggests Water Pik’s legal team engaged promptly. Whether that engagement produced a durable agreement is not publicly known.
Neuralpulse v Water — key questions answered
The dismissal without prejudice means Neuralpulse Ltd. and LuminaThrive LLC retain the right to refile patent infringement claims against Water Pik based on US9642677B2. No merits ruling was issued, no invalidity finding was entered, and Water Pik received no formal legal clearance. The patent’s presumption of validity remains intact.
The asserted patent is US9642677B2 (application number US13/831401), covering water dental flosser technology. The product accused was Water Pik’s Water Dental Flosser product line. No claim construction or validity determination was issued during the 20-day case.
The public record does not disclose the reason for the 20-day dismissal. Possible explanations consistent with the facts include: a confidential settlement or licensing agreement, a negotiated covenant-not-to-sue, or a strategic decision to refile in a different venue or with revised claim mapping. No defendant filing or court order preceded the dismissal.
No. A dismissal without prejudice under Rule 41(a)(1)(A)(i) provides no res judicata protection. Neuralpulse may refile the same claims against Water Pik in any competent U.S. district court, subject to applicable statutes of limitations. Water Pik’s FTO position relative to US9642677B2 remains formally unresolved.
Fed. R. Civ. P. 41(a)(1)(A)(i) allows a plaintiff to dismiss a complaint without a court order before the defendant serves an answer or a motion for summary judgment. In patent cases, this is commonly used to exit litigation before significant costs accrue — often in parallel with settlement negotiations. The dismissal is automatic upon filing and does not require judicial approval.
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