BEUDAMED
    FDA Adverse Event Injury Summary report: N

    NSK

    MDR report key: 7572759 · Received June 6, 2018

    Report

    Report Number
    9611253-2018-00026
    Event Type
    Injury
    Date Received
    June 6, 2018
    Date of Event
    March 19, 2018
    Report Date
    June 27, 2018
    Manufacturer
    NAKANISHI INC.
    Product Code
    EGS
    PMA / PMN Number
    K972569
    Adverse Event
    Yes
    Product Problem
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    WI, US
    Reporter Occupation
    DENTIST

    Narratives

    Additional Manufacturer Narrative · 0

    EXEMPTION NUMBER E2016004. (B)(4). - NSK AMERICA CORP. IS LISTED HERE IN AND MR. (B)(4), BECAUSE MR. (B)(4) IS THE OFFICIAL CORRESPONDENT OF BOTH NAKANISHI (B)(4). NAM WILL CONTINUE TO OBTAIN INFORMATION ABOUT THE PATIENT.

    Additional Manufacturer Narrative · 0

    ON (B)(6) 2018, NAKANISHI RECEIVED FROM NSK AMERICA INFORMATION ABOUT THE PATIENT OTHER THAN THE PATIENT WEIGHT. ACCORDING TO THE NSK AMERICA, THE DENTIST REFUSED TO PROVIDE THE INFORMATION. UPON RECEIVING THE DEVICE INVOLVED IN THE MDR EVENT FROM A DISTRIBUTOR, NAKANISHI CONDUCTED A FAILURE ANALYSIS OF THE RETURNED DEVICE [C180517-04]. THESE ACTIVITIES ARE DESCRIBED IN MORE DETAIL BELOW. METHODOLOGY USED: A) NAKANISHI EXAMINED THE DEVICE HISTORY RECORD AND THE REPAIR HISTORY FOR THE SUBJECT X95L DEVICE [SERIAL NUMBER (B)(4)]. 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 ROTATED IT. HOWEVER, THE HANDPIECE WAS LOCKED AND 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 BEARING RETAINER (BALL RETAINING PART) ON THE REAR SIDE OF THE CARTRIDGE WAS BROKEN. - THE CLUTCH SHAFT WAS STUCK IN THE BODY. - THE HEAD GEAR AND UPPER DRIVE GEAR WERE BROKEN/DAMAGED. - THE CLUTCH WAS CORRODED. B) 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: 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.

    Description of Event or Problem · 0

    ON MAY 17, 2018, NAKANISHI RECEIVED AN E-MAIL FROM A DISTRIBUTOR (B)(4) ABOUT A HANDPIECE OVERHEATING. DETAILS ARE AS FOLLOWS. - THE EVENT OCCURRED ON (B)(6) 2018. - A DENTIST WAS REMOVING DECAY AND PLACING BUCCAL RESTORATIONS ON THE PATIENT TEETH #27 AND 28 USING THE X95L HANDPIECE (SERIAL NO.: (B)(4)). - AFTER ABOUT 30 SECONDS OF USE, THE DENTIST FOUND A WHITE, ROUND LESION ON THE INTRAORAL MUCOSA ADJACENT TO THE TEETH #27 AND 28, WHICH WAS CAUSED BY HEAT FROM THE BACK OF THE HANDPIECE HEAD. - THE LESION WAS ABOUT 5MM BY 5MM, AND APPEARED TO BE RELATIVELY DEEP INTO THE TISSUE. - THE HANDPIECE WAS RUN FOR ANOTHER 30 SECONDS WITHOUT TOUCHING TISSUE AT THIS POINT THE PRODUCT STOPPED FUNCTIONING COMPLETELY, AND WOULD NO LONGER ROTATE. - THE RESTORATION WAS COMPLETED WITH A DIFFERENT DEVICE, AND THE PATIENT LEFT THE DENTAL OFFICE WITH MINIMAL SWELLING. - FOLLOWING THIS EVENT, THE PATIENT HAD SEVERE SWELLING AND VISITED A GENERAL MEDICAL PHYSICIAN TWO TIMES. - AS A CONSEQUENCE, THE PATIENT HAD TO VISIT AN EAR NOSE THROAT SPECIALIST. - THE DENTIST HAS FOLLOWED UP EVERY TWO WEEKS WITH THE PATIENT AND THE PATIENT IS HEALING NORMALLY AND ALMOST FULLY RECOVERED.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    418382 NSK HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL EGS NAKANISHI INC. X95L

    Patients

    Seq Age Sex Outcome Treatment
    1 37 YR Other