BEUDAMED
    FDA Adverse Event Injury Summary report: N

    BRASSELER/NSK

    MDR report key: 8533187 · Received April 19, 2019

    Report

    Report Number
    9611253-2019-00028
    Event Type
    Injury
    Date Received
    April 19, 2019
    Date of Event
    February 5, 2019
    Report Date
    June 11, 2019
    Manufacturer
    NAKANISHI INC.
    Product Code
    EGS
    PMA / PMN Number
    K972569
    Adverse Event
    Yes
    Product Problem
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    SC, US
    Reporter Occupation
    OTHER

    Narratives

    Additional Manufacturer Narrative · 0

    ACCORDING TO THE DISTRIBUTOR, THE DENTIST REFUSED TO PROVIDE THE PATIENT'S WEIGHT. UPON RECEIVING THE DEVICE INVOLVED IN THE MDR EVENT FROM THE DISTRIBUTOR, NAKANISHI CONDUCTED A FAILURE ANALYSIS OF THE RETURNED DEVICE THAT INCLUDED MEASURING THE OPERATING TEMPERATURE OF THE DEVICE [C190405-03]. THESE ACTIVITIES ARE DESCRIBED IN MORE DETAIL BELOW. METHODOLOGY USED: A) NAKANISHI EXAMINED THE DEVICE HISTORY RECORD AND THE REPAIR HISTORY FOR THE SUBJECT TI95L DEVICE [SERIAL NUMBER C6116254]. 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 MOST PROXIMAL TO THE PATIENT (TESTING POINT (1)) AND POINTS FURTHER TOWARD THE DISTAL END OF THE DEVICE (TESTING POINTS (2) THROUGH (4)). 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 DEVICE'S MOTOR AT 40,000 MIN-1, WHICH IS THE MAXIMUM RPM FOR THE MOTOR THAT DRIVES THE HANDPIECE (200,000 MIN-1 FOR THE HANDPIECE), WITH WATER SPRAY, AND MEASURED THE EXOTHERMIC RESPONSE. B.3) NAKANISHI MEASURED THE TEMPERATURE RISE OF THE RETURNED HANDPIECE SET AT 200,000 MIN-1 (MOTOR REVOLUTION 40,000 MIN-1). NAKANISHI OBSERVED AN ABNORMAL TEMPERATURE RISE AT TEST POINTS (1) AND (2) A FEW SECONDS AFTER THE START. TEMPERATURE MEASUREMENTS 37 SECONDS AFTER THE START ARE AS FOLLOWS: - TEST POINT (1): 66.8 DEGREES C - TEST POINT (2): 70.5 DEGREES C - TEST POINT (3): 39.2 DEGREES C - TEST POINT (4): 29.0 DEGREES C THE RISE IN TEMPERATURE WAS SO SUDDEN THAT THE TEST WAS CONCLUDED 37 SECONDS INTO THE PLANNED 5-MINUTE EVALUATION PERIOD. 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 RETAINERS (BALL RETAINING PART) ON THE FRONT AND REAR SIDES OF THE CARTRIDGE WERE BROKEN. - THERE WAS DEBRIS IN THE PUSH BUTTON. - THERE WAS CORROSION ON SEVERAL OF THE GEARS. 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 RETAINERS. NAKANISHI CONSIDERS THE POSSIBILITY FROM MANY YEARS OF EXPERIENCE THAT THE CAUSE OF THE BEARING RETAINERS BEING BROKEN WAS THE INGRESS OF UNDESIRABLE MATERIALS INTO THE BEARINGS. 2) A LACK OF MAINTENANCE CAUSES THE ACCUMULATION OF DEBRIS ON THE INSIDE PARTS, WHICH CAUSES DEBRIS INGRESS INTO THE BEARINGS 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 THE 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

    EXEMPTION NUMBER E2016004. (B)(4). (B)(4) TOOK THE FOLLOWING ACTIONS, BUT FURTHER INFORMATION ABOUT THE EVENT WAS STILL NOT PROVIDED FROM (B)(4)'S DISTRIBUTOR. ON MARCH 21, 2019, (B)(4) RECEIVED A BRASSELER BRANDED TI95L FROM (B)(4) FOR REPAIR. THERE WAS A NOTE WITH THE DEVICE STATING THAT THE HANDPIECE WAS OVERHEATING. ON MARCH 25, 2019, (B)(4) NOTIFIED BRASSELER USA OF THE EVENT BY E-MAIL. NO RESPONSE WAS PROVIDED. (B)(4) IS CURRENTLY TRYING TO CONTACT THE CUSTOMER DIRECTLY TO OBTAIN DETAILS ABOUT THE EVENT, AND WAITING FOR THEIR REPLY.

    Description of Event or Problem · 0

    NAKANISHI RECEIVED FURTHER INFORMATION ABOUT THE EVENT FROM THE DISTRIBUTOR. THE EVENT OCCURRED ON (B)(6) 2019, NOT (B)(6), 2019. THE PROCEDURE THE DENTIST WAS PERFORMING AT THE TIME OF THE EVENT WAS A COMPOSITE FILLING ON UPPER RIGHT TEETH 22B, 21B, 20DO. THE PATIENT WAS UNDER LOCAL ANESTHESIA. DURING THE PROCEDURE, THE DENTIST NOTICED A 1ST DEGREE WHITE BURN LESION ON THE CORNER OF THE PATIENT'S LOWER LIP. THE DENTIST ADMINISTERED VASELINE AND A TOPICAL NSAID AS TREATMENT AT THE TIME OF THE INJURY. THE DENTIST HAS BEEN UNABLE TO VERIFY IF THE INJURY IS HEALING NORMALLY BECAUSE THE PATIENT HAS REFUSED TO RETURN TO THE OFFICE.

    Description of Event or Problem · 0

    ON APRIL 5, 2019, NAKANISHI RECEIVED AN E-MAIL FROM A DISTRIBUTOR ((B)(4)) ABOUT A HANDPIECE OVERHEATING. DETAILS ARE AS FOLLOWS: THE EVENT OCCURRED AROUND (B)(6) 2019 (THE EXACT DATE IS UNKNOWN). A DENTIST WAS PERFORMING A DENTAL PROCEDURE USING THE TI95L HANDPIECE (SERIAL NO. (B)(4)). DURING THE PROCEDURE, THE HANDPIECE OVERHEATED AND BURNED A PATIENT.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    323512 BRASSELER/NSK HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL EGS NAKANISHI INC. TI95L

    Patients

    Seq Age Sex Outcome Treatment
    1 17 YR Other