BEUDAMED
    FDA Adverse Event Malfunction Summary report: N

    NSK

    MDR report key: 23263035 · Received October 9, 2025

    Report

    Report Number
    9611253-2025-00051
    Event Type
    Malfunction
    Date Received
    October 9, 2025
    Date of Event
    September 10, 2025
    Report Date
    October 10, 2025
    Manufacturer
    NAKANISHI INC.
    Product Code
    EGS
    Product Problem
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    JA
    Reporter Occupation
    003

    Narratives

    Additional Manufacturer Narrative · 0

    THIS EVENT OCCURRED IN JAPAN, BUT SIMILAR PRODUCTS ARE MARKETED IN THE US UNDER K972569. THE DENTIST REFUSED TO PROVIDE INFORMATION ABOUT THE PATIENT'S ETHNICITY AND RACE. UPON RECEIVING THE DEVICE INVOLVED IN THE MDR EVENT, NAKANISHI CONDUCTED A FAILURE ANALYSIS OF THE RETURNED DEVICE [REPORT NO. (B)(4)]. THESE ACTIVITIES ARE DESCRIBED IN MORE DETAIL BELOW. METHODOLOGY USED: A) NAKANISHI EXAMINED THE DEVICE HISTORY RECORD AND THE REPAIR HISTORY FOR THE SUBJECT DA-800C5L DEVICE [SERIAL NO.(B)(6)]. THERE WERE NO PROBLEMS OBSERVED DURING MANUFACTURING OR TESTING NOTED IN THE DHR. THERE WERE ALSO NO REPAIR HISTORY RECORDS SINCE THE DEVICE WAS SHIPPED. B) NAKANISHI DISASSEMBLED THE HANDPIECE AND CONDUCTED A VISUAL INSPECTION OF THE INTERNAL PARTS. NAKANISHI OBSERVED THE FOLLOWING: THE PUSH BUTTON AND THE PRESS-FIT RING WERE ABRADED AND SOILED. THE FRONT AND REAR CARTRIDGES WERE DISCOLORED AND SOILED. THE BUR, WHICH RETURNED TOGETHER WITH THE HANDPIECE WAS DISCOLORED AND SCRATCHED. C) NAKANISHI TOOK PHOTOGRAPHS OF ALL THE DISASSEMBLED PARTS AND KEPT THEM IN THE INVESTIGATION REPORT NO. (B)(4). CONCLUSIONS REACHED BASED ON THE INVESTIGATION AND ANALYSIS RESULTS: A) NAKANISHI IDENTIFIED THE CAUSE OF THE HEADCAP SEPARATION FROM THE RETURNED DEVICE WAS REMOVING THE PRESS-FIT RING OUT OF THE HEADCAP DUE TO THE COMBINATION OF WEAR OF INTERNAL PARTS DUE TO AGING TOGETHER WITH CUTTING VIBRATION BASED ON THE FINDINGS IN THE VISUAL INSPECTION. B) USAGE BEYOND THE RECOMMENDED SERVICE LIFE LED TO THE ABOVE ISSUE, WHICH CONTRIBUTED TO THE REPORTED EVENT. C) IN ORDER TO PREVENT A RECURRENCE OF THE HEADCAP SEPARATION, NAKANISHI TOOK THE FOLLOWING ACTIONS: C.1) NAKANISHI REVIEWED THE OPERATION MANUAL AND RECONFIRMED THE CLARITY AND UNDERSTANDABILITY OF THE INSTRUCTIONS. C.2) NAKANISHI WILL REPORT THE ABOVE EVALUATION RESULTS TO THE DENTIST AND REMIND THE DENTIST OF THE IMPORTANCE OF USING THE DEVICE AS INSTRUCTED IN THE OPERATION MANUAL.

    Description of Event or Problem · 0

    ON SEPTEMBER 16, 2025, NAKANISHI RECEIVED AN EMAIL FROM A DISTRIBUTOR ABOUT A MALFUNCTION OF A NSK HANDPIECE. THE DETAILS NAKANISHI OBTAINED ARE AS FOLLOWS. THE EVENT OCCURRED ON (B)(6) 2025. A DENTIST WAS PERFORMING A BRIDGE REMOVAL PROCEDURE ON A PATIENT USING THE DA-800C5L HANDPIECE (SERIAL NO. (B)(6)). DURING THE PROCEDURE, THE HEADCAP AND SPRING OF THE HANDPIECE SUDDENLY CAME OFF FROM THE HANDPIECE AND DROPPED INSIDE THE PATIENT'S MOUTH. THE PARTS WERE RECOVERED IMMEDIATELY, AND THE PATIENT WAS NOT AFFECTED.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    279598 NSK HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL EGS NAKANISHI INC. DA-800C5L

    Patients

    Seq Age Sex Outcome Treatment
    1 78 YR Female Other