BEUDAMED
    FDA Adverse Event Injury Summary report: N

    NSK

    MDR report key: 9509038 · Received December 23, 2019

    Report

    Report Number
    9611253-2019-00060
    Event Type
    Injury
    Date Received
    December 23, 2019
    Date of Event
    December 1, 2019
    Report Date
    December 24, 2020
    Manufacturer
    NAKANISHI INC.
    Product Code
    EGS
    PMA / PMN Number
    K972569
    Adverse Event
    Yes
    Product Problem
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    AZ, US
    Reporter Occupation
    DENTIST

    Narratives

    Additional Manufacturer Narrative · 0

    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 [C191207-01]. THESE ACTIVITIES ARE DESCRIBED IN MORE DETAIL BELOW. METHODOLOGY USED: NAKANISHI EXAMINED THE DEVICE HISTORY RECORD AND THE REPAIR HISTORY FOR THE SUBJECT Z95L DEVICE [SERIAL NO. CBH80529]. 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. 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 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 INTO THE TEST. TEMPERATURE MEASUREMENTS 5 MINUTES AFTER THE START OF THE TEST WERE AS FOLLOWS: TEST POINT (1): 62.4 DEGREES C, TEST POINT (2): 77.9 DEGREES C, TEST POINT (3): 32.4 DEGREES C, TEST POINT (4): 32.9 DEGREES C. IDENTIFICATION OF THE SPECIFIC FAILURE MODE(S) AND/OR MECHANISM(S) OF THE ASSOCIATED DEVICE COMPONENTS WAS CONDUCTED AS FOLLOWS: A) NAKANISHI DISASSEMBLED THE HANDPIECE AND PERFORMED A VISUAL INSPECTION OF THE INTERNAL PARTS. NAKANISHI OBSERVED THE FOLLOWING PHENOMENA: - THE BALL RETAINER ON THE REAR SIDE OF THE CARTRIDGE WAS BROKEN. - THERE WAS DEBRIS ON THE OTHER PARTS. B) NAKANISHI TOOK PHOTOGRAPHS OF ALL OF THE DISASSEMBLED PARTS AND KEPT THEM IN INVESTIGATION REPORT #C191207-01. CONCLUSIONS REACHED BASED ON THE INVESTIGATION AND ANALYSIS RESULTS: A) NAKANISHI IDENTIFIED THAT THE CAUSE OF THE OVERHEATING OF THE RETURNED DEVICE WAS ABNORMAL RESISTANCE DURING ROTATION DUE TO THE BROKEN BEARING RETAINER. NAKANISHI CONSIDERS THE POSSIBILITY FROM MANY YEARS OF EXPERIENCE THAT THE CAUSE OF THE BROKEN BEARING RETAINER WAS THE INGRESS OF UNDESIRABLE MATERIALS INTO THE BEARING. B) A LACK OF MAINTENANCE CAUSED THE ACCUMULATION OF DEBRIS ON THE INTERNAL PARTS, WHICH CAUSED DEBRIS INGRESS INTO THE BEARING DURING ROTATION. THIS CONTRIBUTED TO THE HANDPIECE OVERHEATING. C) IN ORDER TO PREVENT A RECURRENCE OF THE HANDPIECE OVERHEATING, NAKANISHI TOOK THE FOLLOWING ACTIONS: C.1) NAKANISHI REVIEWED THE OPERATION MANUAL AND RECONFIRMED THE CLARITY AND UNDERSTANDABILITY OF THE INSTRUCTIONS. C.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

    THIS SUPPLEMENTAL REPORT IS SENT AS A CORRECTION BECAUSE THE INITIAL REPORT WAS INADVERTENTLY CONSIDERED BY FDA TO BE A SINGLE MDR REPORT. THIS SUPPLEMENT REPORT CLARIFIES THAT 1) THE SAME EVENT WAS INITIALLY REPORTED SEPARATELY BY BOTH THE MANUFACTURER AND THE INITIAL IMPORTER AND 2) THE INITIAL MANUFACTURER REPORT WAS THEREFORE NOT INTENDED AS A SINGLE MDR REPORT. THE ORIGINAL REPORT INCLUDED ON THE FRONT PAGE BOTH THE MANUFACTURER REPORT NUMBER AND THE IMPORTER REPORT NUMBER TO CROSS-REFERENCE EACH REPORT PER "GENERAL INSTRUCTIONS - FOR FORM FDA 3500A MEDWATCH (FOR MANDATORY REPORTING)" (FORM FDA 3500A SUPPLEMENT (4/16) - FORM INSTRUCTIONS). HOWEVER, FDA IS IN THE PROCESS OF UPDATING THE INSTRUCTIONS TO FORM 3500A TO CLARIFY THAT THE CROSS-REFERENCE INFORMATION SHOULD INSTEAD BE PLACED IN SECTION H.10. THIS SUPPLEMENTAL REPORT NOW PLACES THE INITIAL IMPORTER REPORT NUMBER (1422375-2019-00024) IN SECTION H10 ADDITIONAL MANUFACTURER NARRATIVE FOR CROSS-REFERENCE PURPOSES, AS REQUESTED BY FDA.

    Additional Manufacturer Narrative · 1

    NSK AMERICA (NAM) TOOK THE FOLLOWING ACTIONS, BUT FURTHER INFORMATION ABOUT THE EVENT AND PATIENT WAS NOT PROVIDED BY THE DENTIST. ON (B)(6) 2019, NAM RECEIVED INFORMATION ABOUT A PATIENT BURN INJURY FROM CUSTOMER DOCUMENTS INVOLVING TWO DEVICES NEEDING SERVICE. ON DECEMBER 3, 2019, NAM MADE A PHONE CALL TO THE DENTAL OFFICE AND SPOKE WITH THE DENTIST TO REQUEST FURTHER INFORMATION ON THE EVENT. THE DENTIST STATED THAT TWO HANDPIECES HAD BEEN INVOLVED IN TWO SEPARATE ADVERSE EVENTS ON TWO SEPARATE DAYS, BUT COULD NOT PROVIDE ANY SPECIFIC EVENT INFORMATION AT THE TIME OF THE CALL. THE DENTIST PROVIDED AN EMAIL ADDRESS AND PROMISED TO GIVE MORE INFORMATION WHEN THE INFORMATION BECOMES AVAILABLE. ON THE SAME DAY (DECEMBER 3, 2019), NAM SENT AN EMAIL TO THE ADDRESS THE DENTIST PROVIDED REQUESTING INFORMATION ABOUT THE EVENT. NO REPLY TO THE EMAIL REQUEST WAS RECEIVED. ON DECEMBER 6, 2019, A SECOND FOLLOW-UP EMAIL WAS SENT TO THE DENTAL OFFICE. NO REPLY WAS RECEIVED BY NAM. ON DECEMBER 11, 2019, A THIRD EMAIL REQUEST WAS SENT TO THE OFFICE. NO REPLY WAS RECEIVED.

    Description of Event or Problem · 1

    ON DECEMBER 9, 2019, NAKANISHI BECAME AWARE OF A HANDPIECE OVERHEATING THROUGH A COMPLAINT INPUT INTO THE COMPLAINT DATABASE BY A DISTRIBUTOR (NSK AMERICA). DETAILS ARE AS FOLLOWS: THE EVENT OCCURRED AROUND (B)(6) 2019 (EXACT DATE IS UNKNOWN). A DENTIST WAS PERFORMING A DENTAL PROCEDURE ON A PATIENT USING THE Z95L HANDPIECE (SERIAL NO. (B)(4)). DURING THE PROCEDURE, THE HANDPIECE OVERHEATED AND BURNED THE PATIENT.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    1304283 NSK HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL EGS NAKANISHI INC. Z95L

    Patients

    Seq Age Sex Outcome Treatment
    1 Other