BEUDAMED
    FDA Adverse Event Malfunction Summary report: N

    NSK Z95L

    MDR report key: 4690564 · Received April 8, 2015

    Report

    Report Number
    9611253-2015-00036
    Event Type
    Malfunction
    Date Received
    April 8, 2015
    Report Date
    March 30, 2015
    Manufacturer
    NAKANISHI, INC. (NSK)
    Product Code
    EGS
    PMA / PMN Number
    K972569
    Adverse Event
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    JA
    Reporter Occupation
    SERVICE PERSONNEL

    Narratives

    Additional Manufacturer Narrative · 1

    COMPLAINT REVIEW: THERE WAS NO REPAIR HISTORY ON FILE FOR THIS HANDPIECE. INVESTIGATION : ' THE HANDPIECE WAS FORWARDED TO THE MANUFACTURER (NAKANISHI) FOR AN ANALYSIS AND INVESTIGATION ON MAY 27, 2014. AS OF THIS REPORT NO ADDITIONAL INFORMATION HAS BEEN RECEIVED. UPON RECEIPT FROM THE DENTIST OF THE DEVICE INVOLVED IN THE MDR EVENT, NAKANISHI CONDUCTED A FAILURE ANALYSIS OF THE RETURNED DEVICE THAT INCLUDED AN ATTEMPT TO MEASURE THE TEMPERATURE OF THE OPERATING DEVICE (C130329-01-1). THESE ACTIVITIES ARE DESCRIBED IN MORE DETAIL BELOW. METHODOLOGY USED: THE DEVICE WAS CONFIGURED FOR TEMPERATURE TESTING IN THE EXACT STATE IN WHICH IT WAS RETURNED. SPECIFICALLY, NO LUBRICATION OR CLEANING WAS PERFORMED ON THE RETURNED DEVICE BEFORE THIS FIRST TEST IN ORDER TO CHARACTERIZE THE DEVICE UNDER CONDITIONS THAT WOULD DUPLICATE THE USE SITUATION AT THE TIME OF THE EVENT. TEMPERATURE SENSORS WERE FIRST ATTACHED TO THE EXTERIOR OF THE DEVICE AT TWO TEST POINTS (I.E., MOST PROXIMAL TO THE PATIENT AND THE DISTAL END OF THE DEVICE). THE TEST SET UP WAS PREPARED TO TAKE TEMPERATURE MEASUREMENTS AT ALL POINTS SIMULTANEOUSLY, INCLUDING A REFERENCE MEASUREMENT AT AMBIENT ROOM TEMPERATURE. NAKANISHI ATTACHED A THERMOCOUPLE (SENSOR TO MEASURE A TEMPERATURE) TO EACH OF THE TESTING POINTS. NAKANISHI ROTATED THE HANDPIECE AT 40,000 RPM, WHICH IS MAXIMUM RPM FOR THE MOTOR THAT DRIVES THE HANDPIECE (200,000 RPM FOR THE HANDPIECE), WITH WATER SPRAY AND MEASURED THE EXOTHERMIC SITUATION. NAKANISHI MEASURED THE TEMPERATURE RISE OF THE RETURNED HANDPIECE SET AT 200,000 RPM (MOTOR REVOLUTION 40,000 RPM). NAKANISHI CONFIRMED THE TEMPERATURE AT THE HEAD OF THE HANDPIECE ROSE SUDDENLY AFTER THE BEGINNING OF THE MEASUREMENT. IN FACT, THE RISE WAS SO SUDDEN (MORE THAN 61.1 DEGREES AT THE SIDE OF HEAD AND 78.2 DEGREES AT THE HEAD CAP} THAT THE TEST WAS ENDED ONLY 10 SECONDS INTO THE PLANNED 3-MINUTE EVALUATION PERIOD: IDENTIFICATION OF THE SPECIFIC FAILURE MODE(S) AND/OR MECHANISM(S) AND THE ASSOCIATED DEVICE COMPONENTS(S) INVOLVED: NAKANISHI DISASSEMBLED THE HANDPIECE AND PERFORMED A VISUAL INSPECTION OF THE INSIDE PARTS. NAKANISHI OBSERVED DAMAGE ON THE CARTRIDGE BEARING. THE AMOUNT OF OIL OBSERVED INSIDE THE HANDPIECE INDICATED THAT THE DEVICE WAS NOT ADEQUATELY CLEANED. DUE TO THE OIL LEVEL OBSERVED, AS WELL AS THE PRESENCE OF SOME ABRASIVE POWDERS IN THE HANDPIECE, NAKANISHI REASSEMBLED AND WASHED THE HANDPIECE USING NAKANISHI PANA-SPRAY. NAKANISHI OBSERVED DIRT/DEBRIS BEING EXPELLED FROM THE HEAD OF THE HANDPIECE BY USING A WHITE FILTER TO CATCH ANYTHING THAT WAS EXPELLED. AFTER CLEANING AND LUBRICATING, THE HANDPIECE WAS REASSEMBLED AS DEFINED IN THE OPERATIONS MANUAL, NAKANISHI MEASURED THE TEMPERATURE OF THE HANDPIECE. EVEN AFTER CLEANING, NAKANISHI STILL OBSERVED A QUICK RISE IN TEMPERATURE. CONCLUSIONS REACHED BASED ON THE INVESTIGATION AND ANALYSIS RESULTS: NAKANISHI IDENTIFIED THAT THE CAUSE OF OVERHEATING OF THE RETURNED DEVICE WAS DUE TO DAMAGE TO THE CARTRIDGE BEARING. THE DAMAGE OBSERVED CAUSED ABNORMAL ROTATIONAL RESISTANCE, WHICH WOULD RESULT IN THE HANDPIECE OVERHEATING.

    Description of Event or Problem · 1

    THIS MDR IS BEING REPORTED AT THIS TIME AS PART OF OUR INTERNAL REVIEW OF PAST COMPLAINTS AND SERVICE RECORDS. DUE TO THE INCIDENT BEING IN THE PAST, WE ARE LIMITED IN THE INFORMATION THAT WE CAN OBTAIN FROM THE INITIAL COMPLAINANT. THE FOLLOWING INFORMATION IS FROM A DISTRIBUTOR TO NAKANISHI INC. (NSK), REGARDING A DEVICE MANUFACTURED BY NSK. EVENT SUMMARY: ACCORDING TO A DENTIST, THIS ADVERSE EVENT OCCURRED IN THE MIDDLE OF (B)(6) 2014. THE HANDPIECE TOUCHED THE INSIDE OF PATIENT'S MOUTH DURING TREATMENT, AND THE TREATMENT FINISHED WITHOUT ANY COMPLAINT FROM THE PATIENT. THEN THE DENTIST FOUND THAT THE INSIDE OF PATIENT'S MOUTH HAD BEEN BURNED WHITE. THE DENTIST GAVE THE PATIENT AN OINTMENT AND MONITORED THE HEALING PROGRESS.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    230254 NSK Z95L HANDPIECE,CONTRA-AND RIGHT-ANGLE ATTACHMENT,DENTAL, PRODUCT CODE: EGS EGS NAKANISHI, INC. (NSK) Z95L

    Patients

    Seq Age Sex Outcome Treatment
    1 Other