BEUDAMED
    FDA Adverse Event Injury Summary report: N

    NSK

    MDR report key: 6287865 · Received January 30, 2017

    Report

    Report Number
    9611253-2017-00003
    Event Type
    Injury
    Date Received
    January 30, 2017
    Date of Event
    December 29, 2016
    Report Date
    September 14, 2017
    Manufacturer
    NAKANISHI INC.
    Product Code
    EGS
    PMA / PMN Number
    K972569
    Adverse Event
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    IL, US
    Reporter Occupation
    DENTIST

    Narratives

    Additional Manufacturer Narrative · 0

    (B)(4). EXEMPTION NUMBER E2016004.

    Description of Event or Problem · 0

    ON JANUARY 11, 2017, NAKANISHI RECEIVED AN E-MAIL FROM A DISTRIBUTOR (B)(4) ABOUT HANDPIECE PARTS COMING OFF. DETAILS ARE AS FOLLOWS. - ON JANUARY 3, 2017, (B)(4) WAS MADE AWARE BY A NOTE FROM A DENTIST THAT A HEADCAP HAD COME OFF FROM AN NSK HANDPIECE, Z95L (SERIAL NO. (B)(4)) AND A PATIENT HAD SWALLOWED THE HEADCAP. - THERE WAS NO PRIOR REPAIR CONDUCTED AT NSK AMERICA ON THE SUBJECT DEVICE. - AFTER BECOMING AWARE OF THE EVENT, NAM CONTACTED THE DENTIST TO OBTAIN THE FURTHER INFORMATION. - THE EVENT OCCURRED ON (B)(6) 2016. - THE DENTIST WAS PERFORMING AN OCCLUSAL PREPARATION ON THE PATIENT ON TOOTH #18 USING A #6 ROUND BUR.. - THE PATIENT WAS SEDATED UNDER IV (MODERATE). - THE DENTIST HEARD A LOUD NOISE AND FELT THE HANDPIECE BUR WOBBLE. - TWO WASHERS WERE FOUND IN THE POSTERIOR PHARYNX, AND THE PATIENT SWALLOWED THE PUSH BUTTON HEADCAP. - THE ONLY ACTION THE DENTIST TOOK AT THE TIME OF THE EVENT WAS ASPIRATION/SUCTION TO TRY TO PICK UP THE PARTS THAT HAD FALLEN. - ACCORDING TO THE DENTIST, THERE WAS NO INDICATION OF ANY MALFUNCTION OBSERVED WITH THE HANDPIECE PRIOR TO USE. - THE DENTIST STATED THAT THE PATIENT HAD NO HEALTH PROBLEM WHEN THE PATIENT VISITED THE DENTAL OFFICE FOR A FOLLOW-UP AFTER 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 [C170111-01-1]. 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 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. NAKANISHI CONDUCTED A VISUAL INSPECTION OF THE RETURNED DEVICE. OTHER THAN THE HEADCAP MISSING FROM THE HANDPIECE WHEN THE DEVICE WAS RETURNED, THERE WERE NO VISIBLE ABNORMALITIES, SUCH AS CRACKS, DENTS OR DEFORMATION, ON THE OUTSIDE OF THE HANDPIECE. NAKANISHI ALSO OBSERVED NO ABRASIONS, DETERIORATION OR DIMENSIONAL ABNORMALITY OF THE HEAD THREAD IN THE VISUAL INSPECTION. NAKANISHI OBSERVED WHETHER OR NOT A HEADCAP ATTACHED TO THE RETURNED HANDPIECE WOULD LOOSEN UNDER THE FOLLOWING CONDITIONS. A NEW HEADCAP WAS USED FOR THIS TESTING BECAUSE THE HEADCAP INVOLVED IN THE EVENT WAS NOT RETURNED. TIGHTENING TORQUE: 50N?CM (SPECIFICATION AT THE MANUFACTURING)/45N?CM/35N?CM/30N?CM/25N?CM/20N?CM/15N?CM/10N?CM /5N?CM. BUR: TEST BUR (DIA.: 1.598MM, LENGTH: 19.01MM)/2 CARBIDE BURS (DIA.: 1.594MM, LENGTH: 19.40MM & DIA.: 1.594MM, LENGTH: 19.42MM)/DIAMOND BUR (DIA.: 1.592MM, LENGTH: 19.18MM). MOTOR ROTATION SPEED: TEST BUR (40,000RPM)/CARBIDE BUR (40,000RPM)/DIAMOND BUR (16,000RPM) LOAD: UNDER NO-LOAD AND UNDER LOAD (LINE ENGRAVING OF PHOSPHOR BRONZE/MELAMINE PLATE). EVALUATION PERIOD: 3 MINUTES FOR EACH EVALUATION UNDER NO-LOAD AND LOAD. NAKANISHI DREW A LINE ON THE HEADCAP AND HEAD AND OBSERVED FOR MISALIGNMENT AFTER EACH USE. THERE WAS NO HEADCAP LOOSENING OBSERVED UNDER ANY CONDITIONS DESCRIBED ABOVE IN THE EVALUATION. CONCLUSIONS REACHED BASED ON THE INVESTIGATION AND ANALYSIS RESULTS: ALTHOUGH NAKANISHI COULD NOT REPLICATE THE REPORTED EVENT, NAKANISHI CONSIDERS THE POSSIBILITY, FROM SIMILAR PHENOMENON NSK HAS EXPERIENCE IN THE PAST, THAT THE COMBINATION OF A REDUCTION IN HEADCAP TIGHTENING FORCE WITH ABNORMAL VIBRATION (E.G. BUR RUNOUT, CUTTING UNDER HIGH LOAD, ETC.) COULD RESULT IN THE REPORTED HEADCAP LOOSENING/COMING OFF. FAILURE TO CHECK THE HEADCAP TIGHTNESS BEFORE EACH USE AS INSTRUCTED IN THE OPERATION MANUAL, CONTRIBUTES TO THE HEADCAP LOOSENING/COMING OFF WHEN COMBINED WITH ABNORMAL VIBRATION. IN ORDER TO PREVENT A RECURRENCE OF THE HEADCAP LOOSENING/COMING OFF, 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 NSK AMERICA AND DIRECTED NSK AMERICA TO REMIND THE USER OF THE IMPORTANCE OF FOLLOWING INSTRUCTIONS IN THE OPERATION MANUAL.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    68676 NSK HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL EGS NAKANISHI INC. Z95L

    Patients

    Seq Age Sex Outcome Treatment
    1 15 YR Other