BEUDAMED
    FDA Adverse Event Injury Summary report: N

    NSK

    MDR report key: 21802536 · Received April 8, 2025

    Report

    Report Number
    9611253-2025-00012
    Event Type
    Injury
    Date Received
    April 8, 2025
    Date of Event
    March 11, 2025
    Report Date
    April 9, 2025
    Manufacturer
    NAKANISHI INC.
    Product Code
    EFB
    Adverse Event
    Yes
    Product Problem
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    JA
    Reporter Occupation
    003

    Narratives

    Additional Manufacturer Narrative · 0

    THE DENTIST REFUSED TO PROVIDE ANY INFORMATION ABOUT THE PATIENT. THIS EVENT OCCURRED IN JAPAN, BUT SIMILAR PRODUCTS ARE MARKETED IN THE US UNDER K113655. 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 Z800FL DEVICE [(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 CONDUCTED A VISUAL INSPECTION OF THE DEVICE AND OBSERVED THE FOLLOWING: - THE HEADCAP AND CARTRIDGE WERE SEPARATED FROM THE DEVICE. - THE CARTRIDGE WAS DISASSEMBLED. - THE THREADS OF THE HEADCAP AND HEAD WERE NOT ABRADED. C) NAKANISHI MEASURED THE SIZE OF THE BUR RETURNED WITH THE CARTRIDGE AND OBSERVED VALUES OUT OF DEVICE SPECIFICATION. - THE MAXIMUM DIAMETER OF THE WORKING PORTION WAS 3.03MM (SPECIFICATION: 2.00MM). - THE DIAMETER OF THE SHANK WAS 1.587MM (SPECIFICATION: 1.59~1.60MM). D) NAKANISHI MOUNTED A NEW CARTRIDGE TO THE HEAD OF THE HANDPIECE, ATTACHED THE RETURNED BUR TO THE NEW CARTRIDGE AND ROTATED THE HANDPIECE UNDER NO LOAD AND CUT A MELAMINE PLATE WHILE ROTATING THE HANDPIECE TO CHECK WHETHER OR NOT THE HEADCAP WOULD LOOSEN. THE REPORTED LOOSENING OF THE HEADCAP WAS NOT REPLICATED IN THE DEVICE EVALUATION. E) 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) ALTHOUGH NAKANISHI COULD NOT REPLICATE THE REPORTED EVENT, NAKANISHI CONSIDERS THE POSSIBILITY FROM SIMILAR EVENT THAT NSK HAS EXPERIENCED IN THE PAST, THE COMBINATION OF THE REPEATED CUTTING VIBRATION TOGETHER WITH ABNORMAL VIBRATION, WHICH CAUSED BY HIGH-LOAD CUTTING OR USE OF THE OUT-OF-SPECIFICATION BUR, COULD RESULT IN THE REPORTED HEADCAP LOOSENING/SEPARATION. B) MISUSE BY THE USER LED TO THE ABOVE ISSUE, WHICH CONTRIBUTED TO THE REPORTED EVENT. C) IN ORDER TO PREVENT A RECURRENCE OF THE HEADCAP LOOSENING/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 O0F USING THE DEVICE AS INSTRUCTED IN THE OPERATION MANUAL.

    Description of Event or Problem · 0

    ON MARCH 18, 2025, A NSK Z800FL HANDPIECE WAS RETURNED FROM A DISTRIBUTOR TO NAKANISHI FOR REPAIR. THERE WAS A NOTE WITH THE DEVICE STATING THAT THE DEVICE HAD OVERHEATED AND BURNED A PATIENT. UPON RECEIPT OF THE INFORMATION, NAKANISHI MADE A PHONE CALL TO THE DENTAL OFFICE FOR FURTHER INFORMATION ABOUT THE EVENT INCLUDING INFORMATION ABOUT THE PATIENT. THE DETAILS ARE AS FOLLOWS: - THE EVENT OCCURRED ON MARCH 11, 2025. - A DENTIST WAS PREPARING A BRIDGE AND PERFORMING AN OCCLUSAL ADJUSTMENT ON #7 TOOTH OF A PATIENT'S UPPER LEFT JAW USING THE Z800FL HANDPIECE (SERIAL NO. (B)(6)). - THE PATIENT WAS UNDER ANESTHESIA. - DURING THE PROCEDURE, THE HEADCAP POPPED OFF FROM THE HANDPIECE AND THE INTERNAL PARTS DROPPED INSIDE THE PATIENT'S MOUTH. - THE PATIENT DID NOT SWALLOW THE PARTS BUT RECEIVED A SCRATCH INSIDE THEIR MOUTH. - THE DENTIST APPLIED OINTMENT TO THE INJURY OF THE PATIENT. - THE PATIENT IS REPORTED TO HAVE HEALED NORMALLY WITHOUT NEED FOR ADDITIONAL MEDICAL TREATMENT. - ACCORDING TO THE DENTIST, THERE WERE NO ABNORMALITIES OBSERVED IN THE DEVICE PRIOR TO USE.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    1422295 NSK HANDPIECE, AIR-POWERED, DENTAL EFB NAKANISHI INC. Z800FL

    Patients

    Seq Age Sex Outcome Treatment
    1 NA Unknown Other