BEUDAMED
    FDA Adverse Event Injury Summary report: N

    NSK

    MDR report key: 6192912 · Received December 21, 2016

    Report

    Report Number
    9611253-2016-00074
    Event Type
    Injury
    Date Received
    December 21, 2016
    Date of Event
    December 8, 2016
    Report Date
    April 4, 2017
    Manufacturer
    NAKANISHI INC.
    Product Code
    EGS
    Adverse Event
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    JA
    Reporter Occupation
    OTHER

    Narratives

    Additional Manufacturer Narrative · 1

    AS OF DECEMBER 20, 2016, NAKANISHI IS STILL CONTACTING THE DISTRIBUTOR FOR MORE INFORMATION, INCLUDING PATIENT INFORMATION. THIS EVENT OCCURRED IN (B)(6), BUT SIMILAR PRODUCTS ARE MARKETED IN THE US UNDER (B)(4).

    Additional Manufacturer Narrative · 1

    NAKANISHI TRIED TO OBTAIN THE PATIENT WEIGHT FROM THE DENTIST, BUT THE DENTIST DID NOT PROVIDE THE INFORMATION. UPON RECEIVING THE DEVICE INVOLVED IN THE MDR EVENT FROM A DISTRIBUTOR, NAKANISHI CONDUCTED A FAILURE ANALYSIS OF THE RETURNED DEVICE THAT INCLUDED MEASURING THE TEMPERATURE OF THE OPERATING DEVICE [C161214-01-1]. THESE ACTIVITIES ARE DESCRIBED IN MORE DETAIL BELOW. METHODOLOGY USED: A) NAKANISHI EXAMINED THE DEVICE HISTORY RECORD AND THE REPAIR HISTORY FOR THE SUBJECT EVA-Y 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. SINCE THE EVA-Y WAS USED WITH THE HANDPIECE, EC-30 AT THE TIME OF THE EVENT, NAKANISHI CONNECTED THE HEAD TO THE HANDPIECE AND ACTIVATED THE MOTOR AT 10,000 MIN-1 (THE MAXIMUM ROTATION SPEED FOR THE HEAD) FOR AN OPERATION TEST. THE DEVICE DID NOT MAKE A VERTICAL RECIPROCATING MOTION AS INTENDED. NAKANISHI CONDUCTED TEMPERATURE TESTING OF THE RETURNED DEVICE IN THE FOLLOWING MANNER: 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. NAKANISHI ATTACHED A THERMOCOUPLE (SENSOR TO MEASURE A TEMPERATURE) TO EACH OF THE TESTING POINTS. NAKANISHI ROTATED THE DEVICE'S MOTOR AT 10,000 MIN-1, WHICH IS THE MAXIMUM RPM FOR THE MOTOR THAT DRIVES THE HANDPIECE (10,000 MIN-1 FOR THE HANDPIECE), AND MEASURED THE EXOTHERMIC SITUATION. NAKANISHI MEASURED THE TEMPERATURE RISE OF THE RETURNED HANDPIECE SET AT 10,000 MIN-1 (MOTOR REVOLUTION 10,000 MIN-1). NAKANISHI DID NOT OBSERVE A TEMPERATURE RISE HIGH ENOUGH TO CAUSE A BURN INJURY AT ANY OF THE TEST POINTS DURING THE TEST PERIOD. 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 EXTREME ABRASION ON THE PLUNGER AND CAM. NAKANISHI TOOK PHOTOGRAPHS OF ALL OF THE DISASSEMBLED PARTS AND KEPT THEM IN A FILE. 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 EXCESSIVE OUTPUT DUE TO THE ABRADED INSIDE PARTS. A LACK OF MAINTENANCE CAUSES ABRASION ON THE INSIDE PARTS LEADING 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 CHECKING THE HANDPIECE PRIOR TO USE TO PREVENT OVERHEATING AS INSTRUCTED IN THE OPERATION MANUAL.

    Description of Event or Problem · 1

    ON (B)(6) 2016, AN NSK HANDPIECE HEAD, EVA-Y, WAS RETURNED FROM A DISTRIBUTOR TO NAKANISHI FOR REPAIR. THERE WAS A NOTE WITH THE DEVICE STATING A HANDPIECE HAD OVERHEATED. THE ONLY INFORMATION NAKANISHI OBTAINED FROM THE NOTE ABOUT THE EVENT IS AS FOLLOWS. THE EVENT OCCURRED ON (B)(6) 2016.. A DENTIST WAS PROVIDING A PATIENT WITH A DENTAL TREATMENT USING A 2-PIECE DEVICE: EVA-Y (SERIAL NO. (B)(4)) AND EC-30 (SERIAL NO. (B)(4)).- THE HANDPIECE SUDDENLY OVERHEATED AND BURNED THE CORNER OF THE PATIENT'S MOUTH.

    Description of Event or Problem · 1

    THE DETAILED INFORMATION ABOUT THE EVENT THAT NAKANISHI DID NOT ACQUIRE AT THE TIME OF INITIAL REPORT IS AS FOLLOWS: THE DENTIST WAS STRIPPING A RIGHT PREMOLAR OF THE PATIENT'S LOWER JAW USING THE DEVICE. THE PATIENT WAS NOT UNDER ANESTHESIA. DURING THE PROCEDURE, THE PATIENT COMPLAINED ABOUT PAIN IN THE LIPS. RIGHT AFTER HEARING THE COMPLAINT, THE DENTIST COOLED THE LIP DOWN. THE DENTIST DETERMINED MEDICAL INTERVENTION FOR THE BURN INJURY WAS NOT NEEDED. THE DENTIST WAS AWARE THAT THE TEMPERATURE OF THE HANDPIECE WAS HIGHER THAN USUAL, PRIOR TO THE PROCEDURE.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    843872 NSK HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL EGS NAKANISHI INC. EVA-Y

    Patients

    Seq Age Sex Outcome Treatment
    1 23 YR Other