BEUDAMED
    FDA Adverse Event Summary report: N

    NSK

    MDR report key: 4928310 · Received July 16, 2015

    Report

    Report Number
    9611253-2015-00100
    Date Received
    July 16, 2015
    Date of Event
    June 17, 2015
    Report Date
    July 14, 2015
    Manufacturer
    NAKANISHI INC.
    Product Code
    EGS
    PMA / PMN Number
    K972569
    Adverse Event
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    JA
    Reporter Occupation
    OTHER

    Narratives

    Additional Manufacturer Narrative · 1

    UPON RECEIPT OF THE DEVICE INVOLVED IN THE MDR EVENT, NAKANISHI CONDUCTED A FAILURE ANALYSIS OF THE RETURNED DEVICE THAT INCLUDED MEASUREMENT OF THE TEMPERATURE OF THE OPERATING DEVICE (C150702-18-1). THESE ACTIVITIES ARE DESCRIBED IN MORE DETAIL BELOW. METHODOLOGY USED: NAKANISHI EXAMINED THE DEVICE HISTORY RECORD FOR THE SUBJECT TI-MAX TI95EX DEVICE (SERIAL NUMBER (B)(4)). THERE WERE NO PROBLEMS OBSERVED DURING THE MANUFACTURING OR TESTING NOTED IN THE DHR. NAKANISHI PERFORMED A SIMPLE MOVEMENT TEST. NAKANISHI SET A TEST BUR IN THE HANDPIECE AND ROTATED IT BY HAND. NAKANISHI OBSERVED THAT THE BUR DID NOT ROTATE SMOOTHLY, WHICH INDICATES HIGH ROTATION RESISTANCE. NAKANISHI CONDUCTED A TEMPERATURE TESTING OF THE RETURNED DEVICE IN THE FOLLOWING MANNER: TEMPERATURE SENSORS WERE FIRST ATTACHED TO THE EXTERIOR OF THE DEVICE AT VARIOUS TEST POINTS (E.G., MOST PROXIMAL TO THE PT AND ALONG POINTS FURTHER TOWARD THE DISTAL END OF THE DEVICE). THE TEST SETUP WAS PREPARED TO TAKE TEMPERATURE MEASUREMENTS AT ALL POINTS SIMULTANEOUSLY; NAKANISHI ATTACHED A THERMOCOUPLE (SENSOR TO MEASURE A TEMPERATURE) TO EACH OF THE TESTING POINTS 1, 2, 3 AND 4. 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 OBSERVED THE ABNORMAL TEMPERATURE RISE (68.1 DEGREES C) AT THE TEST POINT, WHERE IS THE HEADCAP PUSH BUTTON OF THE HANDPIECE, AFTER THE BEGINNING OF THE MEASUREMENT. THE RISE WAS SO SUDDEN THAT THE TEMPERATURE 68.1 DEGREES C WAS CONFIRMED ONLY 100 SECONDS INTO THE PLANNED 5 MINUTES EVALUATION PERIOD. IDENTIFICATION OF THE SPECIFIC FAILURE MODE(S) AND/OR MECHANISM(S) AND THE ASSOCIATED DEVICE COMPONENT(S) INVOLVED: NAKANISHI DISASSEMBLED THE HANDPIECE AND PERFORMED A VISUAL INSPECTION OF THE INSIDE PARTS. NAKANISHI OBSERVED ABRASION AND ABRASIVE POWDER ACCUMULATED IN EACH INNER PART; NAKANISHI TOOK PHOTOGRAPHS OF ALL THE ABRASION AND ABRASIVE POWDER MENTIONED ABOVE AND KEPT THEM IN A FILE. CONCLUSIONS REACHED BASED ON THE INVESTIGATION AND ANALYSIS RESULTS: NAKANISHI IDENTIFIED THAT THE CAUSE OF OVERHEATING OF THE RETURNED DEVICE WAS DUE TO ABRASION AND ACCUMULATION OF ABRASIVE POWDER IN THE INNER PARTS; A LACK OF MAINTENANCE CAUSES ABRASION AND ACCUMULATION OF THE POWDER IN THE INNER PARTS, WHICH CAUSED ABNORMAL ROTATION RESISTANCE, RESULTING IN THE HANDPIECE OVERHEATING; IN ORDER TO PREVENT A RECURRENCE OF THE HANDPIECE OVERHEATING, NAKANISHI REMINDED THE DENTIST OF THE IMPORTANCE OF MAINTAINING THE DEVICE AND PRIOR-TO-USE CHECKUPS AS THE OPERATION MANUAL DIRECTS.

    Description of Event or Problem · 1

    ON (B)(6) 2015, NAKANISHI RECEIVED THE INFORMATION THAT A DENTIST BURNED A PATIENT DURING A DENTAL SURGERY. NAKANISHI CONTACTED THE DENTIST AND OBTAINED THE FOLLOWING DETAILED INFORMATION. THE DENTIST WAS SEPARATING A CROWN OF AN IMPACTED TOOTH IN MANDIBLE USING A TI95EX (CONTRA-ANGLE HANDPIECE) CONNECTED TO SURGICPRO PLUS (SURGICAL MOCROMOTOR SYSTEM ) WITH SALINE SPRAYED. DURING THE SURGERY, THE DENTIST BURNED THE PATIENT ON THE CHEEK MUCOSA, WHERE THE HANDPIECE WAS COMING IN CONTACT WITH. THE BURN WAS CAUSED DUE TO OVERHEATING OF THE HANDPIECE. THE DENTIST HAS NOT RECEIVED ANY COMPLAINT FROM THE PATIENT. THE HANDPIECE INVOLVED IN THE EVENT WAS SENT TO THE MANUFACTURER FOR INVESTIGATION.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    463994 NSK HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL EGS NAKANISHI INC. TI95EX

    Patients

    Seq Age Sex Outcome Treatment
    1 Other