BEUDAMED
    FDA Adverse Event Injury Summary report: N

    NSK

    MDR report key: 7066550 · Received November 29, 2017

    Report

    Report Number
    9611253-2017-00064
    Event Type
    Injury
    Date Received
    November 29, 2017
    Date of Event
    October 31, 2017
    Report Date
    December 12, 2017
    Manufacturer
    NAKANISHI INC.
    Product Code
    EGS
    PMA / PMN Number
    K972569
    Adverse Event
    Yes
    Product Problem
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    JA
    Reporter Occupation
    OTHER

    Narratives

    Additional Manufacturer Narrative · 1

    UPON RECEIVING THE DEVICE INVOLVED IN THE MDR EVENT FROM A DISTRIBUTOR, NAKANISHI CONDUCTED A FAILURE ANALYSIS OF THE RETURNED DEVICE [C171107-03]. THESE ACTIVITIES ARE DESCRIBED IN MORE DETAIL BELOW. METHODOLOGY USED: NAKANISHI EXAMINED THE DEVICE HISTORY RECORD AND THE REPAIR HISTORY FOR THE SUBJECT Z95L DEVICE [SERIAL NUMBER (B)(4)]. THERE WERE NO PROBLEMS OBSERVED DURING THE MANUFACTURING OR TESTING NOTED IN THE DHR. THE REPAIR HISTORY SHOWED 2 SERVICE RECORDS (MARCH 2017 AND JULY 2017) SINCE THE DEVICE WAS SHIPPED. ACCORDING TO THE SERVICE RECORDS, AFTER REPAIRING THE HANDPIECE (REPLACEMENT OF CARTRIDGE, DRIVE SHAFT AND DOG CLUTCH FOR BOTH OF THE REPAIRS), NAKANISHI PERFORMED ALL OF THE NECESSARY OPERATION CHECKS AND CONFIRMED THAT ALL OF THE CRITERIA WERE MET. NAKANISHI SET A TEST BUR IN THE HANDPIECE AND ROTATED IT BY HAND AS A SIMPLE MOVEMENT TEST. THE BUR DID NOT ROTATE AT ALL. THEREFORE, NAKANISHI COULD NOT CONDUCT TEMPERATURE TESTING OF THE DEVICE. IDENTIFICATION OF THE SPECIFIC FAILURE MODE(S) AND/OR MECHANISM(S) AND THE ASSOCIATED DEVICE COMPONENTS INVOLVED: NAKANISHI DISASSEMBLED THE HANDPIECE AND PERFORMED A VISUAL INSPECTION OF THE INSIDE PARTS. NAKANISHI OBSERVED THAT THE BALL BEARING ON THE CARTRIDGE REAR SIDE WAS BROKEN. NAKANISHI TOOK PHOTOGRAPHS OF ALL OF THE DISASSEMBLED PARTS AND KEPT THEM IN THE INVESTIGATION REPORT #(B)(4). CONCLUSIONS REACHED BASED ON THE INVESTIGATION AND ANALYSIS RESULTS: 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. A LACK OF MAINTENANCE CAUSES THE ACCUMULATION OF DIRT IN THE INSIDE PARTS, WHICH CAUSES DIRT INGRESS INTO THE BEARING DURING ROTATION, LEADING TO THE BROKEN BEARING. THIS CONTRIBUTES TO THE HANDPIECE OVERHEATING. IN ORDER TO PREVENT A RECURRENCE OF THE HANDPIECE OVERHEATING, NAKANISHI TOOK THE FOLLOWING ACTIONS: NAKANISHI REVIEWED THE OPERATION MANUAL AND RECONFIRMED CLARITY AND UNDERSTANDABILITY OF THE INSTRUCTIONS. NAKANISHI REPORTED THE ABOVE EVALUATION RESULTS TO THE DENTIST AND REMINDED THE DENTIST OF THE IMPORTANCE OF MAINTENANCE, AS INSTRUCTED IN THE OPERATION MANUAL.

    Additional Manufacturer Narrative · 1

    WHEN NAKANISHI CONTACTED THE DENTIST FOR INFORMATION ABOUT THE EVENT, THE DENTIST REFUSED TO PROVIDE THE PATIENT IDENTIFIER AND WEIGHT.

    Description of Event or Problem · 1

    ON (B)(6) 2017, AN NSK HANDPIECE Z95L WAS RETURNED FROM A DISTRIBUTOR TO NAKANISHI FOR REPAIR. THERE WAS A NOTE WITH THE DEVICE STATING THAT THE DEVICE HAD OVERHEATED. UPON RECEIPT OF THE INFORMATION, NAKANISHI MADE A PHONE CALL TO THE DENTIST TO OBTAIN DETAILED INFORMATION. THE INFORMATION NAKANISHI RECEIVED FROM THE DENTIST IS AS FOLLOWS. THE DETAILS ARE AS FOLLOWS. - THE EVENT OCCURRED IN (B)(6) 2017. - A DENTIST WAS REMOVING CROWNS FROM TEETH #6 AND #7 OF THE PATIENT'S UPPER RIGHT JAW USING THE HANDPIECE Z95L (SERIAL NO. (B)(4)). - DURING THE PROCEDURE, THE PATIENT COMPLAINED ABOUT THE HANDPIECE OVERHEATING. - THE DENTIST FOUND ABOUT 1-3 MILLIMETERS BURN INJURIES ON THE MUCOSA OF THE PATIENT'S RIGHT CHEEK AND ON THE CORNER OF THE MOUTH. - THE PATIENT WAS NOT UNDER ANESTHESIA. - THE DENTIST WAS AWARE OF UNSTABLE MOTOR ROTATION PRIOR TO USE. - THE DENTIST DETERMINED THAT NO MEDICAL INTERVENTION WAS NECESSARY.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    847029 NSK HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL EGS NAKANISHI INC. Z95L

    Patients

    Seq Age Sex Outcome Treatment
    1 40 YR Other