BEUDAMED
    FDA Adverse Event Injury Summary report: N

    NSK

    MDR report key: 20356030 · Received October 2, 2024

    Report

    Report Number
    9611253-2024-00049
    Event Type
    Injury
    Date Received
    October 2, 2024
    Date of Event
    August 13, 2024
    Report Date
    October 3, 2024
    Manufacturer
    NAKANISHI INC.
    Product Code
    EBW
    PMA / PMN Number
    K163402
    Adverse Event
    Yes
    Product Problem
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    OK, US
    Reporter Occupation
    DENTIST
    Health Professional
    Yes

    Narratives

    Additional Manufacturer Narrative · 0

    THE DENTIST REFUSED TO PROVIDE INFORMATION ABOUT THE PATIENT'S AGE, WEIGHT, ETHNICITY, AND RACE. UPON RECEIVING THE DEVICE INVOLVED IN THE MDR EVENT FROM THE DISTRIBUTOR, NAKANISHI CONDUCTED A FAILURE ANALYSIS OF THE RETURNED DEVICE, WHICH INCLUDED MEASURING THE OPERATING TEMPERATURE OF THE DEVICE [REPORT NO. C240910-01]. THESE ACTIVITIES ARE DESCRIBED IN MORE DETAIL BELOW. METHODOLOGY USED: A) NAKANISHI EXAMINED THE DEVICE HISTORY RECORD AND THE REPAIR HISTORY FOR THE SUBJECT NLZ MOTOR [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 CONDUCTED TEMPERATURE TESTING OF THE RETURNED DEVICE IN THE FOLLOWING MANNER: B.1) TEMPERATURE SENSORS WERE ATTACHED TO THE EXTERIOR OF THE DEVICE AT VARIOUS TEST POINTS. THIS INCLUDED THE POINT CLOSEST TO THE HANDPIECE (TESTING POINT (1)) AND POINTS FURTHER TOWARD THE DISTAL END OF THE DEVICE (TESTING POINTS (2) AND (3)). THE TEST SETUP WAS PREPARED TO TAKE TEMPERATURE MEASUREMENTS AT ALL POINTS SIMULTANEOUSLY, INCLUDING A REFERENCE MEASUREMENT AT AMBIENT ROOM TEMPERATURE. B.2) NAKANISHI ATTACHED A THERMOCOUPLE (SENSOR TO MEASURE TEMPERATURE) TO EACH OF THE TESTING POINTS. NAKANISHI ROTATED THE MOTOR AT 40,000MIN-1, WHICH IS THE MAXIMUM RPM, AND MEASURED THE EXOTHERMIC RESPONSE. B.3) NAKANISHI DID NOT OBSERVE RISES IN TEMPERATURE AT THE TEST POINTS. THE MAXIMUM TEMPERATURE MEASURED 5 MINUTES INTO THE TEST WERE AS FOLLOWS: - TEST POINT (1): 24.1 DEGREES C. - TEST POINT (2): 26.4 DEGREES C. - TEST POINT (3): 26.1 DEGREES C. IDENTIFICATION OF THE SPECIFIC FAILURE MODE(S) AND/OR MECHANISM(S) OF THE ASSOCIATED DEVICE COMPONENTS WAS CONDUCTED AS FOLLOWS: A) NAKANISHI DISASSEMBLED THE HANDPIECE AND PERFORMED A VISUAL INSPECTION OF THE INTERNAL PARTS. NAKANISHI OBSERVED THE FOLLOWING: - THERE WERE SEVERAL DENTS ON THE MOTOR CASE. - THE INSERT WAS SOILED AND THE CLUTCH WAS ABRADED. - THERE WERE TRACES THAT OIL HAD COME INTO THE MOTOR FROM THE OUTSIDE. B) NAKANISHI TOOK PHOTOGRAPHS OF ALL THE DISASSEMBLED PARTS AND KEPT THEM IN THE INVESTIGATION REPORT NO. C240910-01. CONCLUSIONS REACHED BASED ON THE INVESTIGATION AND ANALYSIS RESULTS: A) NAKANISHI COULD NOT IDENTIFY THE EXACT CAUSE OF OVERHEATING OF THE RETURNED DEVICE BECAUSE NAKANISHI WAS NOT ABLE TO REPLICATE THE TEMPERATURE RISE AT THE TIME OF THE EVENT AND DID NOT OBSERVE ANY ABNORMALITIES IN THE VISUAL INSPECTION. B) IN SPITE OF THE FACT THAT NAKANISHI COULD NOT IDENTIFY THE CAUSE, NAKANISHI TOOK THE FOLLOWING ACTIONS TO BE SAFE: B.1) NAKANISHI REVIEWED THE OPERATION MANUAL AND RECONFIRMED THE CLARITY AND UNDERSTANDABILITY OF THE INSTRUCTIONS. B.2) NAKANISHI REPORTED THE ABOVE EVALUATION RESULTS TO THE DISTRIBUTOR AND DIRECTED THE DISTRIBUTOR TO REMIND THE USER OF THE IMPORTANCE OF PRE-USE CHECK AND OF MAINTENANCE AS INSTRUCTED IN THE OPERATION MANUAL.

    Description of Event or Problem · 0

    ON SEPTEMBER 10, 2024, NAKANISHI BECAME AWARE OF A MOTOR OVERHEATING THROUGH A COMPLAINT INPUT INTO THE COMPLAINT DATABASE BY A DISTRIBUTOR (NSK AMERICA). DETAILS ARE AS FOLLOWS: - THE EVENT OCCURRED ON AUGUST 13, 2024. - THE PATIENT RECEIVED A THERMAL BURN INJURY TO THEIR LOWER LIP AND INSIDE OF THEIR CHEEK FROM THE NLZ MOTOR (SERIAL NO. (B)(6)). - THE DENTIST HAD JUST FINISHED WORKING ON TOOTH#17 AND DID NOT NOTICE ANY HEAT BECAUSE OF WHERE HE HOLDS THE HANDPIECE WHILE USING IT. - THE DENTAL ASSISTANT WAS USING THE HANDPIECE TO POLISH AND CLEAN THE MARGIN FOR A TEMPORARY CROWN ON TOOTH#30 WHEN SHE FELT THAT THE MOTOR WAS EXTREMELY HOT. IT WAS THEN THAT THEY OBSERVED THE BURN INJURY. - THE ATTACHMENT USED ON THE MOTOR WAS THE HENRY SCHEIN BRAND MAXIMA ELITE 2 (SERIAL NO. (B)(6)). - THE DENTIST HAS HAD A FOLLOW-UP VISIT WITH HIS PATIENT AND SHE IS REPORTED TO BE HEALING NORMALLY.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    1138487 NSK CONTROLLER, FOOT, HANDPIECE AND CORD EBW NAKANISHI INC. NLZ

    Patients

    Seq Age Sex Outcome Treatment
    1 NA Female Other