BEUDAMED
    FDA Adverse Event Injury Summary report: N

    NSK

    MDR report key: 6857604 · Received September 12, 2017

    Report

    Report Number
    9611253-2017-00045
    Event Type
    Injury
    Date Received
    September 12, 2017
    Date of Event
    July 27, 2017
    Report Date
    October 5, 2017
    Manufacturer
    NAKANISHI INC.
    Product Code
    EGS
    PMA / PMN Number
    K972569
    Adverse Event
    Yes
    Product Problem
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    CA, US
    Reporter Occupation
    DENTIST

    Narratives

    Additional Manufacturer Narrative · 0

    EXEMPTION NUMBER E2016004. NAKANISHI INC. (MANUFACTURER) IS SUBMITTING THE REPORT ON BEHALF OF (B)(4). (B)(4). (B)(4) IS LISTED HERE IN AND MR. (B)(4) BECAUSE MR. (B)(4) IS THE OFFICIAL CORRESPONDENT OF BOTH NAKANISHI INC. AND (B)(4). NAM TOOK THE FOLLOWING ACTIONS TO OBTAIN THE DETAILED INFORMATION ABOUT THE EVENT AND PATIENT, HOWEVER, THE PATIENT'S WEIGHT, ETHNICITY AND RACE WERE NOT PROVIDED. ON (B)(4) 2017, IMMEDIATELY AFTER BECOMING AWARE OF THE EVENT, NAM CONTACTED THE DENTAL OFFICE AND SPOKE WITH A DENTAL ASSISTANT. IN THE CONVERSATION, NAM PROMISED THE ASSISTANT TO SEND THE (B)(4) INFORMATION FORM QA-011. ON (B)(4) 2017, NAM CONTACTED THE DENTAL OFFICE BY PHONE AND LEFT A VOICE MAIL MESSAGE. NO RESPONSE WAS RECEIVED FROM THE DENTAL OFFICE. ON (B)(6) 2017, NAM SENT AN E-MAIL TO THE DENTAL ASSISTANT TO REQUEST TO RETURN THE COMPLETED QA-011 INFORMATION FORM. NAM ALSO LEFT A VOICE MAIL MESSAGE, BUT RECEIVED NO RESPONSE. ON (B)(6) 2017, NAM RECEIVED A CALL FROM THE ASSISTANT, BUT NO FURTHER INFORMATION WAS PROVIDED, BECAUSE THE DENTAL OFFICE INSISTED ON HANDLING THE ISSUE ON THEIR OWN. ON (B)(6) 2017, NAM MADE A PHONE CALL TO THE DENTAL OFFICE TO SPEAK WITH THE DENTIST, BUT THE DENTIST WAS NOT AVAILABLE. ON (B)(6) 2017, NAM SPOKE WITH THE DENTIST AND THE DENTIST AGREED TO FORWARD THE PATIENT INFORMATION TO NAM. ON (B)(6) 2017, THE INFORMATION FORM WAS SENT BACK TO NAM, BUT THE PATIENT'S WEIGHT, ETHNICITY AND RACE WERE NOT PROVIDED.

    Description of Event or Problem · 0

    ON (B)(6) 2017, NAKANISHI RECEIVED AN E-MAIL FROM A DISTRIBUTOR (B)(4) THAT A HANDPIECE HAD OVERHEATED AND BURNED THREE PATIENTS. NAKANISHI IS SUBMITTING THREE SEPARATE MDRS BASED ON THIS COMMUNICATION. THIS MDR IS REGARDING THE THIRD PATIENT. DETAILS ARE AS FOLLOWS. ON (B)(6) 2017, (B)(4) WAS MADE AWARE OF THE EVENT BY COMMUNICATION WITH AN (B)(4) SALES REPRESENTATIVE. THE EVENT OCCURRED ON (B)(6) 2017. A DENTIST WAS PERFORMING A COMPOSITE RESTORATION USING AN (B)(4) HANDPIECE, Z95L (SERIAL NO.: (B)(4) ). DURING THE PROCEDURE, THE HANDPIECE PUSH BUTTON HALF SLANTED IN, OVERHEATED AND BURNED THE INSIDE OF THE PATIENT'S CHEEK. THE PATIENT WAS UNDER LOCAL ANESTHESIA. NO BURN TREATMENT WAS PROVIDED TO THE PATIENT, AND NO PATIENT FOLLOW-UP IS SCHEDULED. THE PATIENT MAY HAVE PERMANENT PARESTHESIA, BUT THIS IS YET TO BE DETERMINED, ACCORDING TO THE DENTIST. THERE WERE NO ABNORMALITIES OR MALFUNCTION OBSERVED WITH THE HANDPIECE PRIOR TO THE EVENT.

    Additional Manufacturer Narrative · 1

    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 OPERATING TEMPERATURE OF THE DEVICE [C170823-03]. THESE ACTIVITIES ARE DESCRIBED IN MORE DETAIL BELOW. METHODOLOGY USED: A) NAKANISHI EXAMINED THE DEVICE HISTORY RECORD AND THE REPAIR HISTORY FOR THE SUBJECT Z95L DEVICE [SERIAL NUMBER (B)(4)]. THERE WERE NO PROBLEMS OBSERVED DURING THE MANUFACTURING OR TESTING NOTED IN THE DHR. THERE WERE NO RECORDS INDICATING NAKANISHI (THE MANUFACTURER) REPAIRED THE DEVICE SINCE THE DEVICE WAS SHIPPED. NSK AMERICA (NAM) ALSO DID NOT PROVIDE REPAIR SERVICE FOR THE DEVICE, HOWEVER, ACCORDING TO THE DENTIST, THE HANDPIECE WAS REPAIRED AT A FACILITY OTHER THAN NAM. THE DENTAL OFFICE IS IN POSSESSION OF THE SERVICE RECORD, BUT DID NOT PROVIDE THE RECORD TO NAM. B) NAKANISHI CONDUCTED A VISUAL INSPECTION OF THE RETURNED DEVICE. NAKANISHI OBSERVED THE FOLLOWING PHENOMENA: THE HEADCAP REMAINED PRESSED IN THE HANDPIECE (SLIDING FAILURE). THERE WAS BREAKAGE OF AND EVIDENCE OF CONTACT WITH THE PUSHER OF THE CARTRIDGE AND DEBRIS ON THE BEARING IN THE HEADCAP. THERE WAS EVIDENCE OF CONTACT WITH THE HEADCAP ON THE PUSHER OF THE CARTRIDGE. C) NAKANISHI TOOK PHOTOGRAPHS OF ALL OF THE OBSERVED PARTS AND KEPT THEM IN A FILE. D) NAKANISHI CONDUCTED TEMPERATURE TESTING OF THE RETURNED DEVICE IN THE FOLLOWING MANNER: D.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. D.2) NAKANISHI ATTACHED A THERMOCOUPLE (SENSOR TO MEASURE A 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. D.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 POINT (2) A FEW SECONDS AFTER THE START. TEMPERATURE MEASUREMENTS 9 SECONDS AFTER THE START ARE AS FOLLOWS: TEST POINT (1): 42.6 DEGREES C; TEST POINT (2): 139.7 DEGREES C; TEST POINT (3): 30.1 DEGREES C; TEST POINT (4): 27.8 DEGREES C. THE RISE IN TEMPERATURE WAS SO SUDDEN THAT THE TEST WAS CONCLUDED 9 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. B) NAKANISHI TOOK PHOTOGRAPHS OF ALL OF THE DISASSEMBLED PARTS AND KEPT THEM IN A FILE. C) NAKANISHI THEN REPLACED THE DEPRESSED HEADCAP WITH A NEW HEADCAP AND MEASURED THE EXOTHERMIC SITUATION YET AGAIN. THERE WAS NO ABNORMAL RISE IN TEMPERATURE DURING THE 300-SECOND-TEST PERIOD (SEE BELOW). NAKANISHI CONFIRMED THAT THE RETURNED HANDPIECE WAS OPERATING AS EXPECTED AND WITHIN TEMPERATURE SPECIFICATIONS ONCE THE DEPRESSED HEADCAP HAD BEEN REPLACED. TEST POINT (1): 41.9 DEGREES C; TEST POINT (2): 45.7 DEGREES C; TEST POINT (3): 38.9 DEGREES C; TEST POINT (4): 39.6 DEGREES C. CONCLUSIONS REACHED BASED ON THE INVESTIGATION AND ANALYSIS RESULTS: 1) NAKANISHI IDENTIFIED THAT THE CAUSE OF THE OVERHEATING OF THE RETURNED DEVICE WAS FRICTION HEAT GENERATED BY CONTACT BETWEEN THE HEADCAP AND THE PUSHER OF THE CARTRIDGE, WHICH WAS CAUSED BY THE HEADCAP BEING DEPRESSED DURING ROTATION (SLIDING FAILURE). 2) MISUSE BY THE USER LEADS TO THE CONTACT BETWEEN THE HEADCAP AND THE PUSHER OF THE CARTRIDGE, WHICH CONTRIBUTES TO THE REPORTED OVERHEATING. 3) APPROPRIATENESS OF THE REPAIR CONDUCTED BY A DIFFERENT COMPANY COULD NOT BE FULLY EVALUATED BECAUSE THE REPAIR RECORD HAD NOT BEEN PROVIDED BY THE DENTAL OFFICE. 4) IN ORDER TO PREVENT A RECURRENCE OF THE HANDPIECE OVERHEATING, NAKANISHI TOOK THE FOLLOWING ACTIONS: 4.1) NAKANISHI REVIEWED THE OPERATION MANUAL AND RECONFIRMED CLARITY AND UNDERSTANDABILITY OF THE INSTRUCTIONS. 4.2) NAKANISHI REPORTED THE ABOVE EVALUATION RESULTS TO NSK AMERICA AND DIRECTED NSK AMERICA TO REMIND THE USER OF THE IMPORTANCE OF USING THE DEVICE, AS INSTRUCTED IN THE OPERATION MANUAL. 4.3) NAKANISHI ALSO DIRECTED NSK AMERICA TO TELL THE DENTAL OFFICE TO HAVE THE HANDPIECE REPAIRED AT NSK AMERICA WHEN NECESSARY TO AVOID ANY UNEXPECTED MALFUNCTION CAUSED BY INAPPROPRIATE REPAIR.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    638635 NSK HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL EGS NAKANISHI INC. Z95L

    Patients

    Seq Age Sex Outcome Treatment
    1 17 YR Other