BEUDAMED
    FDA Adverse Event Injury Summary report: N

    NSK

    MDR report key: 19835005 · Received July 26, 2024

    Report

    Report Number
    9611253-2024-00037
    Event Type
    Injury
    Date Received
    July 26, 2024
    Date of Event
    July 8, 2024
    Report Date
    August 29, 2024
    Manufacturer
    NAKANISHI INC.
    Product Code
    EFB
    Adverse Event
    Yes
    Product Problem
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    JA
    Reporter Occupation
    DENTIST
    Health Professional
    Yes

    Narratives

    Additional Manufacturer Narrative · 0

    THIS EVENT OCCURRED IN JAPAN, BUT SIMILAR PRODUCTS ARE MARKETED IN THE US UNDER K962543. THE DENTIST REFUSED TO PROVIDE INFORMATION ABOUT THE PATIENT'S WEIGHT AND GENDER.

    Additional Manufacturer Narrative · 0

    UPON RECEIVING THE DEVICE INVOLVED IN THE MDR EVENT, NAKANISHI CONDUCTED A FAILURE ANALYSIS OF THE RETURNED DEVICE, WHICH INCLUDED MEASURING THE OPERATING TEMPERATURE OF THE DEVICE [REPORT NO. (B)(4)]. THESE ACTIVITIES ARE DESCRIBED IN MORE DETAIL BELOW. METHODOLOGY USED: A) NAKANISHI COULD NOT EXAMINE THE DEVICE HISTORY RECORD FOR THE SUBJECT TI-MAX AS600L DEVICE [SERIAL NO. (B)(6)] BECAUSE NAKANISHI HAD DISCARDED THE DHR FOR THE DEVICE THAT HAD EXCEEDED 15-YEAR DOCUMENT RETENTION PERIOD IN ACCORDANCE WITH THE NAKANISHI'S REGULATION. NAKANISHI EXAMINED THE REPAIR HISTORY FOR THE SUBJECT TI-MAX AS600L DEVICE [SERIAL NO. (B)(6)]. THE REPAIR HISTORY SHOWED (B)(4) SERVICE RECORDS SINCE THE DEVICE WAS SHIPPED. THE REPAIRS DETAILS ARE AS FOLLOWS: - (B)(6) 2013: THE JOINT ASSY. AND ELBOW WERE REPLACED. WITH RESPECT TO THE REPAIRS IN THE ABOVE LIST, THE SERVICE RECORDS INDICATE THAT NAKANISHI PERFORMED ALL OF THE NECESSARY OPERATION CHECKS AND CONFIRMED THAT ALL OF THE CRITERIA WERE MET. B) NAKANISHI CONDUCTED TEMPERATURE TESTING OF THE RETURNED DEVICE IN THE FOLLOWING MANNER: B.1) TEMPERATURE SENSORS WERE ATTACHED TO THE EXTERIOR OF THE HANDPIECE HEAD AT 2 TEST POINTS. THIS INCLUDED THE SIDE OF THE HEAD (TESTING POINT (1)) AND PUSH BUTTON OF THE HEAD (TESTING POINTS (2)). THE TEST SETUP WAS PREPARED TO TAKE TEMPERATURE MEASUREMENTS AT BOTH 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 HANDPIECE AT 0.27MPA, WHICH IS THE MAXIMUM AIR PRESSURE FOR THE DEVICE, WITH WATER SPRAY, AND MEASURED THE EXOTHERMIC RESPONSE. B.3) NAKANISHI MEASURED THE TEMPERATURE RISE OF THE RETURNED HANDPIECE SET AT 0.27MPA. THE MAXIMUM TEMPERATURE MEASURED IN THE 5-MINUTE TEST WERE AS FOLLOWS: - TEST POINT (1): 25.5 DEGREES C - TEST POINT (2): 25.1 DEGREES C NAKANISHI DID NOT OBSERVE TEMPERATURES HIGH ENOUGH TO CAUSE A BURN INJURY. 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 CONTACT TRACES ON THE SURFACES OF THE CARTRIDGE AND HEADCAP CAUSED BY A PUSH BUTTON BEING PRESSED. B) NAKANISHI TOOK PHOTOGRAPHS OF ALL THE DISASSEMBLED PARTS AND KEPT THEM IN THE INVESTIGATION REPORT NO. (B)(4). CONCLUSIONS REACHED BASED ON THE INVESTIGATION AND ANALYSIS RESULTS: A) NAKANISHI DID NOT IDENTIFY THE EXACT CAUSE OF OVERHEATING OF THE RETURNED DEVICE BECAUSE NAKANISHI WAS NOT ABLE TO REPLICATE THE TEMPERATURE RISE AT THE TIME OF THE EVENT, BUT BASED ON THE FINDINGS IN THE VISUAL INSPECTION, AS WELL AS MANY YEARS OF EXPERIENCE, NAKANISHI CONSIDERS THE POSSIBILITY THAT THE CAUSE OF THE HANDPIECE OVERHEATING WAS FRICTIONAL HEAT GENERATED BY CONTACT BETWEEN THE HEADCAP AND THE CARTRIDGE, WHICH WAS CAUSED BY THE PUSH BUTTON BEING PRESSED DURING ROTATION. B) MISUSE BY THE USER LEADS TO THE CONTACT BETWEEN THE HEADCAP AND THE CARTRIDGE, WHICH 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 THE DENTIST AND REMINDED THE DENTIST OF THE IMPORTANCE OF USING THE DEVICE AND CHECKING OF THE HANDPIECE PRIOR TO USE TO PREVENT OVERHEATING, AS INSTRUCTED IN THE OPERATION MANUAL.

    Description of Event or Problem · 0

    ON (B)(6) 2024, NAKANISHI RECEIVED A PHONE CALL FROM A DENTAL OFFICE ABOUT AN NSK HANDPIECE OVERHEATING. THE DETAILS NAKANISHI OBTAINED ARE AS FOLLOWS: THE EVENT OCCURRED ON JULY 8, 2024. THE DENTIST WAS PERFORMING A CROWN REMOVAL PROCEDURE ON A PATIENT USING THE TI-MAX AS600L HANDPIECE (SERIAL NO. (B)(6). DURING THE PROCEDURE, THE PATIENT COMPLAINED OF FEELING HOT, AND THEN THE DENTIST OBSERVED 1-CM BURN INJURY WITH BLISTERING ON THEIR LIP.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    946239 NSK HANDPIECE, AIR-POWERED, DENTAL EFB NAKANISHI INC. TI-MAX AS600L

    Patients

    Seq Age Sex Outcome Treatment
    1 70 YR Male Other