510(k) Report

510(k) · Cleared

Cleared

Air Motor (Model name: FX204 M4); Air Motor (Model name: M205)

K233308510(k) TraditionalCleared Apr 25, 2024209-day reviewClass I21 CFR 872.4200

Data to Oct 25, 2026 (FDA decisions) Oct 12, 2026 (recalls) Sep 30, 2026 (MAUDE) refreshed weekly, last Nov 3, 2026

Nakanishi, Inc. · EFB Handpiece, Air-Powered, Dental

Cleared on Apr 25, 2024 as substantially equivalent to K143704 (W&H Dentalwerk Buermoos GmbH, 2015) and 1 other predicate after a 209-day review. Its family tree reaches back 5 generations to 1998.

Decided
Apr 25, 2024
Review
209 days
Class
Class I
Product code
EFB
Recalls
None
Predicates
2

Its longest line of descent runs back 5 generations to K983183 (1998). 8 ancestors in all. No later device cites it as a predicate yet.

  1. Root · 5 generations backK983183 Gyro Long-Life,Black Pearl Eco, Ondine &Croma, Prestige, Bora…Bien Air USA, Inc. · 1998
  2. 4 generations backK031145 Estylus Electric Motor SystemDentsply Intl. · 2003
  3. 3 generations backK072989 Axis SystemDentsply Intl., Inc. · 2008
  4. 2 generations backK143704 Advanced Air SystemW&H Dentalwerk Buermoos GmbH · 2015
  5. 1 generation backK162926 Air-Powered Handpieces and Handpiece AttachmentsW&H Dentalwerk Burmoos GmbH · 2017
  6. This deviceK233308 Air Motor (Model name: FX204 M4); Air Motor (Model name: M205)Nakanishi, Inc. · 2024
View FIG. 1 as a table

Line of descent and top descendants

GenerationNumberDeviceApplicantDecidedRecalls
−5K983183Gyro Long-Life,Black Pearl Eco, Ondine &Croma, Prestige, Bora, Aquilon…Bien Air USA, Inc.1998—
−4K031145Estylus Electric Motor SystemDentsply Intl.2003—
−3K072989Axis SystemDentsply Intl., Inc.2008—
−2K143704Advanced Air SystemW&H Dentalwerk Buermoos GmbH2015—
−1K162926Air-Powered Handpieces and Handpiece AttachmentsW&H Dentalwerk Burmoos GmbH2017—
0 (this device)K233308Air Motor (Model name: FX204 M4); Air Motor (Model name: M205)Nakanishi, Inc.2024—

Other ancestors by year cleared

Year clearedDevicesWith a Class I recall
200120
200710
FIG. 1 — Lineage of K233308, 1998–2024Source: FDA 510(k) summaries, read by 510(k) Report · How lineage is built

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Notable FDA decisions, review times and new Class I recalls. See an issue.

Sources: FDA 510(k) database (decision fields), the FDA summary (predicates and indications), FDA recall and enforcement reports, and MAUDE; processed by 510(k) Report. Verify on FDA.gov · Methodology and accuracy.

Planning a device in EFB? A 510(k) Report weighs predicate choices, recall history and review times for a new device like this one.

Top candidate predicates for a new EFB device

  1. #1 K262144 DIAMED Handpiece;DIAMED Airmotor;DIAMED…score 13.3 · 5 generations · no Class I recall
  2. #2 Held for the reportin the report
  3. #3 Held for the reportin the report
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What was it cleared against? (2)

Devices the submitter claimed this one is substantially equivalent to (*), and reference devices cited for a specific test or feature (†), as written in the FDA summary.

TypeNumberDeviceApplicantDecidedRecalls
*K143704Advanced Air System
Summary page 5
…assification Name: Handpiece, Air-Powered, Dental Regulation Number: 872.4200 Device Class: I Product Codes: EFB Legally Marketed Predicate Devices Predicate Device #: K143704 Predicate Trade Name: Advanced Air System Product Code: EFB Reference Device #: K162926 Predicate Trade Name: W&H Air-Powered Ha…
W&H Dentalwerk Buermoos GmbH2015—
*K162926Air-Powered Handpieces and Handpiece Attachments
Summary page 5
…ss: I Product Codes: EFB Legally Marketed Predicate Devices Predicate Device #: K143704 Predicate Trade Name: Advanced Air System Product Code: EFB Reference Device #: K162926 Predicate Trade Name: W&H Air-Powered Handpieces And Handpiece Attachments Product Code: EFB Device Description Summary The air…
W&H Dentalwerk Burmoos GmbH2017—

Also cleared against K143704: 1 other device →

What descends from it?

No later submission names this one as a predicate yet.

Has anything in its family been recalled? (0 Class I)

No FDA recall names this device.

No ancestor or descendant has a Class I recall.

What does this lineage say?

  • The line of descent spans 26 years and passes through 6 companies; a new generation was cleared every 4.6 years on median.
  • None of the 8 ancestors has a recall.
  • 1 other device also cites its predicate K143704.

How does its category compare?

All EFB devices

EFB Handpiece, Air-Powered, Dental: FDA decisions, review times, recalls and adverse event reports over 20 years. 2024, this device’s year, is highlighted.

FDA decisions per year · EFB

1in 2025

2007: 122008: 72009: 112010: 82011: 42012: 82013: 32014: 72015: 72016: 32017: 72018: 32019: 32020: 52021: 22022: 52023: 42024: 52025: 12026 (partial year): 4
2007high 12 (2007) · low 1 (2025)2026

2026 to Oct 25, outlined.

Median 510(k) review, days · EFB

209in 2024

2007: 61 days median2008: 97 days median2009: 120 days median2010: 116 days median2011: 168 days median2012: 130 days median2013: 207 days median2014: 200 days median2015: 296 days median2016: 205 days median2017: 246 days median2018: 210 days median2019: 348 days median2020: 259 days median2022: 430 days median2023: 158 days median2024: 209 days median2026 (partial year): 252 days median
2007high 430 (2022) · low 61 (2007)2026

Receipt to decision; years with fewer than 3 clearances left blank.

Recalls per year · EFB

No recall names EFB since 2007.

Adverse event reports per year · EFB

83in 2025

2007: 132008: 192009: 402010: 782011: 962012: 972013: 612014: 732015: 872016: 1222017: 1532018: 812019: 1172020: 942021: 1232022: 1572023: 1162024: 1042025: 83
2007high 157 (2022) · low 13 (2007)2025

MAUDE reports naming product code EFB, not matched to any one device; reports are not rates.

View these four charts as a table
YearDecisionsMedian 510(k) review, daysRecalls (Class I)MAUDE reports
20071261013
2008797019
200911120040
20108116078
20114168096
20128130097
20133207061
20147200073
20157296087
201632050122
201772460153
20183210081
201933480117
20205259094
20212—0123
202254300157
202341580116
202452090104
20251—083
202642520—

What is it indicated for?

Air Motor is intended for the following application(s): Driving the handpiece for the tooth restoration, prophylaxis, and root canal preparation.

Indications for use as stated in the FDA summary.

Cite this page

510(k) Report. “K233308: Air Motor (Model name: FX204 M4); Air Motor (Model name: M205).” Lineage record from FDA 510(k) data and the FDA summary. Updated Nov 3, 2026. Accessed Nov 3, 2026. https://510kreport.com/device/K233308

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Record history
  • FDA decision record loaded May 2, 2026
  • Summary read Oct 13, 2026 (extraction version 9eaa42aa01ed)
  • Lineage and recalls computed Nov 3, 2026
  • Page last updated Nov 3, 2026