MAUDE Adverse Event Report: NAKANISHI INC. NSK; HANDPIECE, AIR-POWERED, DENTAL

Model Number S-MAX M500L

Device Problems Mechanical Problem (1384); Device Slipped (1584); Detachment of Device or Device Component (2907)

Patient Problems Tissue Damage (2104); Injury (2348); Patient Problem/Medical Problem (2688)

Event Date 01/25/2019

Event Type  Injury  

Manufacturer Narrative

The dentist refused to provide the patient's id and weight.This event occurred in (b)(6), but similar products are marketed in the us under (b)(4).

Event Description

On (b)(6) 2019, nakanishi received a phone call from an oem about a patient's injury involving an nsk handpiece.According to the oem, one of four handpieces, da-390 (serial no.(b)(4)) or da-391 (serial no.(b)(4) or (b)(4)) caused the event described below.The dentist could not identify which of the four devices actually was involved in the event.The details of the event are: the event occurred on (b)(6) 2019.The dentist attached the one of the above handpieces to the coupling and rotated the device in the patient's mouth.The patient was not under anesthesia.Suddenly, the coupling along with the hose popped out of the handpiece when pressure was applied.The dentist lost hold of the handpiece causing it to contact and cut the inside of the patient's mouth.Since the injury was injury, the dentist determined that no medical attention was required for the injury.According to the dentist, there were no abnormalities in the device observed prior to use.Nakanishi is submitting four separate mdrs for this event based on the information from the oem.This mdr is regarding the da-391 handpiece (serial no.(b)(4)).

Manufacturer Narrative

On (b)(6)2019 , nakanishi found that the 4 handpieces reported in the initial reports (mdr#9611253-2019-00007, #9611253-2019-00009, #9611253-2019-00010, #9611253-2019-00011) as devices that may have been involved in the event were not da-390 (serial no.(b)(4) ) and da-391 (serial no.02300207 or 02300208).The handpieces were da-390 (serial no.(b)(4) ) and s-max m500l (serial no.(b)(4) ).Nakanishi also found that there was another handpiece (s-max m500l, serial no.(b)(4) ) in addition to the four suspected devices.Upon receiving the device involved in the mdr event, nakanishi conducted a failure analysis of the returned device [c190129-06].These activities are described in more detail below.Methodology used: a) nakanishi examined the device history record and the repair history for the subject s-max m500l device [serial number(b)(4) ].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.B) nakanishi conducted a visual inspection of the returned device and performed a manual reproducibility test.There was no problem connecting the handpiece with the coupling.Nakanishi then pulled the handpiece by hand from the coupling without pulling the connector ring of the coupling to see whether or not the handpiece was removed from the coupling.Nakanishi did not observe the handpiece removal as reported by the user.C) nakanishi supplied the handpiece with air with the manufacturer's recommended pressure (0.25mpa) and stopped supplying repeatedly (100 times) to replicate the reported phenomenon.Separation of the handpiece from the coupling was not observed during the test.D) nakanishi evaluated pull length of the handpiece by pulling the handpiece from the coupling using force specified in the specifications (100n or greater).The handpiece did not separate from the coupling.Conclusions reached based on the investigation and analysis results: 1) nakanishi could not identify the exact cause of the handpiece separating from the coupling because nakanishi was not able to replicate the phenomenon during testing and did not observe any abnormalities in the visual inspection.2) in spite of the fact that nakanishi did not identify the cause, nakanishi considers the possibility from many years of experience that the cause of the handpiece separation from the coupling was that the connector ring of the coupling was accidentally pulled in the lock release direction by external factors or that the connection was temporarily unstable due to foreign materials.3) carelessness by the user causes erroneous operation leading to the reported handpiece separation.4) in order to prevent a recurrence of the handpiece separating from the coupling, nakanishi reported the above evaluation results to the dentist and urged the dentist to exercise caution in use of the device.

• Brand Name: NSK
• Type of Device: HANDPIECE, AIR-POWERED, DENTAL
• Manufacturer (Section D): NAKANISHI INC.; 700 shimohinata; kanuma-shi, tochigi-ken 322-8 666; JA 322-8666
• MDR Report Key: 8348279
• MDR Text Key: 136490956
• Report Number: 9611253-2019-00010
• Device Sequence Number: 1
• Product Code: EFB
• Combination Product (y/n): N
• PMA/PMN Number: K962543
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: foreign,other
• Type of Report: Initial,Followup
• Report Date: 03/21/2019

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 02/18/2019
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: S-MAX M500L
• Device Catalogue Number: P1001
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 02/27/2019
• Date Manufacturer Received: 03/08/2019
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Other
• Patient Age: 70 YR