BEUDAMED
    FDA Adverse Event Injury Summary report: N

    NSK

    MDR report key: 8430212 · Received March 18, 2019

    Report

    Report Number
    9611253-2019-00015
    Event Type
    Injury
    Date Received
    March 18, 2019
    Date of Event
    February 15, 2019
    Report Date
    May 10, 2019
    Manufacturer
    NAKANISHI INC.
    Product Code
    EGS
    PMA / PMN Number
    K972569
    Adverse Event
    Yes
    Product Problem
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    CA
    Reporter Occupation
    DENTIST

    Narratives

    Additional Manufacturer Narrative · 0

    UPON RECEIVING THE DEVICE INVOLVED IN THE MDR EVENT FROM A DISTRIBUTOR, NAKANISHI CONDUCTED A FAILURE ANALYSIS OF THE RETURNED DEVICE [C190222-04]. THESE ACTIVITIES ARE DESCRIBED IN MORE DETAIL BELOW. METHODOLOGY USED: A) NAKANISHI EXAMINED THE DEVICE HISTORY RECORD AND THE REPAIR HISTORY FOR THE SUBJECT Z85L DEVICE [SERIAL NUMBER ABG30060]. THERE WERE NO PROBLEMS OBSERVED DURING THE MANUFACTURING OR TESTING NOTED IN THE DHR. THERE WERE ALSO NO REPAIR HISTORY RECORDS SINCE THE DEVICE WAS SHIPPED. B) NAKANISHI SET A TEST BUR IN THE HANDPIECE, CONNECTED THE HANDPIECE TO THE MOTOR AND TRIED TO ROTATE THE MOTOR. HOWEVER, THE HANDPIECE WAS LOCKED AND THE MOTOR DID NOT ROTATE AT ALL. THEREFORE, NAKANISHI WAS NOT ABLE TO CONDUCT TEMPERATURE TESTING OF THE DEVICE. IDENTIFICATION OF THE SPECIFIC FAILURE MODE(S) AND/OR MECHANISM(S) AND THE ASSOCIATED DEVICE COMPONENTS INVOLVED: A) NAKANISHI DISASSEMBLED THE HANDPIECE AND PERFORMED A VISUAL INSPECTION OF THE INSIDE PARTS. NAKANISHI OBSERVED THE FOLLOWING PHENOMENA: - THE BALL BEARING IN THE CARTRIDGE WAS BROKEN. - THERE WAS DEBRIS ON THE OTHER PARTS. B) NAKANISHI TOOK PHOTOGRAPHS OF ALL OF THE DISASSEMBLED PARTS AND KEPT THEM IN THE INVESTIGATION REPORT #C190222-04. CONCLUSIONS REACHED BASED ON THE INVESTIGATION AND ANALYSIS RESULTS: 1) NAKANISHI IDENTIFIED THAT THE CAUSE OF THE OVERHEATING OF THE RETURNED DEVICE WAS ABNORMAL RESISTANCE DURING ROTATION CAUSED BY THE BROKEN BEARING DUE TO THE INGRESS OF UNDESIRABLE MATERIALS INTO THE BEARING. 2) A LACK OF MAINTENANCE CAUSES THE ACCUMULATION OF DEBRIS ON THE INSIDE PARTS, WHICH CAUSES DEBRIS INGRESS INTO THE BEARING DURING ROTATION. THIS CONTRIBUTES TO THE HANDPIECE OVERHEATING. 3) IN ORDER TO PREVENT A RECURRENCE OF THE HANDPIECE OVERHEATING, NAKANISHI TOOK THE FOLLOWING ACTIONS: 3.1) NAKANISHI REVIEWED THE OPERATION MANUAL AND RECONFIRMED CLARITY AND UNDERSTANDABILITY OF THE INSTRUCTIONS. 3.2) NAKANISHI REPORTED THE ABOVE EVALUATION RESULTS TO NSK AMERICA AND DIRECTED NSK AMERICA TO REMIND THE USER OF THE IMPORTANCE OF MAINTENANCE, AS INSTRUCTED IN THE OPERATION MANUAL.

    Additional Manufacturer Narrative · 0

    (B)(4). EXEMPTION NUMBER E2016004.

    Description of Event or Problem · 0

    ON FEBRUARY 21, 2019, NAKANISHI RECEIVED AN E-MAIL FROM A DISTRIBUTOR ((B)(4)) ABOUT A HANDPIECE OVERHEATING. DETAILS ARE AS FOLLOWS. THE EVENT OCCURRED ON (B)(6) 2019. THE DENTIST WAS PERFORMING A CROWN PREPARATION FOR THE PATIENT'S TOOTH #37 USING THE Z85L HANDPIECE (SERIAL NO. (B)(4)). THE PATIENT WAS UNDER LOCAL ANESTHESIA. DURING THE PROCEDURE, THE DENTIST NOTICED THAT THE HANDPIECE HEAD WAS HEATING UP AND FOUND A CIRCULAR BURN ABOUT THE SIZE OF A CANADIAN TWO-DOLLAR COIN (28MM DIAMETER) ON THE LEFT DORSAL AND VENTRAL SURFACE OF THE PATIENT'S TONGUE. THE DENTIST PRESCRIBED PERIOPLUS RINSE AND ORACORT TO THE PATIENT. THE INJURY WAS FOUND TO BE HEALING NORMALLY UPON FOLLOW-UP VISIT WITH THE PATIENT. THE DENTIST DETERMINED THAT NO FURTHER MEDICAL ATTENTION WAS REQUIRED FOR THE INJURY.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    220701 NSK HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL EGS NAKANISHI INC. Z85L

    Patients

    Seq Age Sex Outcome Treatment
    1 50 YR Other