BEUDAMED
    FDA Adverse Event Injury Summary report: N

    NSK

    MDR report key: 21684933 · Received March 25, 2025

    Report

    Report Number
    9611253-2025-00006
    Event Type
    Injury
    Date Received
    March 25, 2025
    Date of Event
    February 28, 2025
    Report Date
    March 25, 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

    THIS EVENT OCCURRED IN JAPAN, BUT SIMILAR PRODUCTS ARE MARKETED IN THE US UNDER K203791. THE DENTIST REFUSED TO PROVIDE INFORMATION ABOUT THE PATIENT'S WEIGHT. 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 S-ML 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 PERFORMED A MANUAL REPRODUCIBILITY TEST. THERE WAS NO PROBLEM CONNECTING THE RETURNED HANDPIECE WITH THE LED COUPLING [SERIAL NO. (B)(6)] RETURNED TOGETHER WITH THE HANDPIECE. NAKANISHI THEN PULLED THE HANDPIECE BY HAND FROM THE COUPLING WITHOUT PULLING THE CONNECTOR RING OF THE COUPLING TO SEE WHETHER OR NOT THE HANDPIECE WAS REMOVED FROM THE COUPLING. NAKANISHI DID NOT OBSERVE THE HANDPIECE REMOVAL AS REPORTED BY THE USER. C) NAKANISHI SUPPLIED THE HANDPIECE WITH AIR WITH THE MANUFACTURER'S RECOMMENDED PRESSURE (0.28MPA) AND STOPPED SUPPLYING REPEATEDLY TO REPLICATE THE REPORTED PHENOMENON. SEPARATION OF THE HANDPIECE FROM THE COUPLING WAS NOT OBSERVED DURING THE TEST. D) NAKANISHI EVALUATED PULL-OUT STRENGTH OF THE HANDPIECE BY PULLING THE HANDPIECE FROM THE COUPLING USING FORCE SPECIFIED IN THE SPECIFICATIONS (100N OR GREATER). THE HANDPIECE DID NOT SEPARATE FROM THE COUPLING. E) NAKANISHI CONDUCTED A VISUAL INSPECTION OF THE HANDPIECE AND COUPLING AND OBSERVED THAT THE O-RING AT THE JOINT OF THE HANDPIECE WAS BROKEN AND THE INSERT OF THE COUPLING WAS SLIGHTLY ABRADED BUT COULD NOT OBSERVE ANY ABNORMALITIES IN THE DIMENSIONS OF THE JOINT OF THE HANDPIECE AND COUPLING OR THE SLIDING OF THE CONNECTOR RING. F) NAKANISHI TOOK PHOTOGRAPHS OF ALL THE PARTS AND KEPT THEM IN THE INVESTIGATION REPORT NO.(B)(4). CONCLUSIONS REACHED BASED ON THE INVESTIGATION AND ANALYSIS RESULTS: A) NAKANISHI COULD NOT IDENTIFY THE EXACT CAUSE OF THE HANDPIECE SEPARATING FROM THE COUPLING BECAUSE NAKANISHI WAS NOT ABLE TO REPLICATE THE PHENOMENON DURING TESTING AND DID NOT OBSERVE ANY ABNORMALITIES IN THE VISUAL INSPECTION. B) IN SPITE OF THE FACT THAT NAKANISHI DID NOT IDENTIFY THE CAUSE, NAKANISHI CONSIDERS THE POSSIBILITY FROM MANY YEARS OF EXPERIENCE IN THE LOCK RELEASE BY EXTERNAL FACTORS OR THAT THE CONNECTION WAS TEMPORARILY UNSTABLE DUE TO FOREIGN MATERIALS. C) CARELESSNESS BY THE USER CAUSES ERRONEOUS OPERATION LEADING TO THE REPORTED HANDPIECE SEPARATION. D) IN ORDER TO PREVENT A RECURRENCE OF THE HANDPIECE SEPARATION FROM THE COUPLING, NAKANISHI TOOK THE FOLLOWING ACTIONS: D.1) NAKANISHI REVIEWED THE OPERATION MANUAL AND RECONFIRMED THE CLARITY AND UNDERSTANDABILITY OF THE INSTRUCTIONS. D.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 (B)(6) 2025, NAKANISHI RECEIVED A PHONE CALL FROM A DISTRIBUTOR ABOUT A MALFUNCTION OF AN NSK HANDPIECE. THE DETAILS NAKANISHI OBTAINED ARE AS FOLLOWS: - THE EVENT OCCURRED ON (B)(6) 2025. - A DENTIST WAS PERFORMING AN OCCLUSAL ADJUSTMENT ON TEETH NUMBER SIX AND SEVEN OF A PATIENT USING THE S-ML HANDPIECE (SERIAL NO. (B)(6)) AND THE LED COUPLING (SERIAL NO. (B)(6)) AFTER REMOVING CARIES AND FILLING CAVITIES. - THE PATIENT WAS UNDER LOCAL ANESTHESIA. - DURING THE PROCEDURE, THE HANDPIECE CAME OUT OF THE COUPLING AND STUCK IN THE BACK OF THE PATIENT'S THROAT. - THE DENTIST CARRIED OUT PRESSURE HEMOSTASIS TO THE INJURY. - 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
    1696196 NSK HANDPIECE, AIR-POWERED, DENTAL EFB NAKANISHI INC. S-ML

    Patients

    Seq Age Sex Outcome Treatment
    1 26 YR Male Other