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

Model Number M800WL

Device Problem Detachment of Device or Device Component (2907)

Patient Problem No Clinical Signs, Symptoms or Conditions (4582)

Event Date 10/19/2020

Event Type  malfunction  

Manufacturer Narrative

Nakanishi did not receive any information about the patient, and is still waiting for the information from the distributor.Upon receiving the device involved in the mdr event from the distributor, nakanishi conducted a failure analysis of the returned device.These activities are described in more detail below.Methodology used: nakanishi examined the device history record and the repair history for the subject m800wl device [serial no.(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.Nakanishi conducted a visual inspection of the returned device and observed that the cartridge cap was stuck on the headcap, and both the cartridge cap and headcap were removed from the device.Nakanishi also confirmed that the cartridge case was broken.After replacing the broken cartridge with a new cartridge and setting, the returned headcap in the handpiece, nakanishi observed whether or not the headcap would loosen by rotating and then cutting a melamine plate.There was no headcap loosening observed in the evaluation.Nakanishi, then disassembled the handpiece and performed a visual inspection of the internal parts.Nakanishi observed the following phenomena: there were contact traces produced by friction heat on the surface of the push button.The cartridge bearing was abraded, soiled, and discolored.Nakanishi took photographs of all the disassembled parts and kept them in investigation report #(b)(4).Conclusions reached based on the investigation and analysis results: nakanishi could not replicate the headcap separation at the time of the event, however, based on the abnormality of the internal parts observed in the visual inspection, as well as many years of experience, nakanishi determined that the cause of the reported separation was abnormal vibration generated by contact with the push button or abrasion/debris of the cartridge bearing.In addition, some strong impact on the device or repeated cutting vibration may also have contributed to the headcap loosening.A lack of maintenance caused the accumulation of debris on the internal parts, and failure to check the handpiece before use led to user ignorance of abnormalities in the internal parts, which contributed to the headcap separation.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 the user and reminded the user of the importance of maintenance and checking of the handpiece prior to use to prevent headcap separation/coming off, as instructed in the operation manual.

Event Description

On october 21, 2020, nakanishi received a phone call from a distributor about a malfunction of an nsk handpiece.The information nakanishi obtained from the communication is as follows: the event occurred on (b)(6) 2020.The dentist was performing a dental procedure on a patient using the m800wl handpiece (serial no.(b)(4)).During the procedure, the headcap separated from the head, and the cartridge came out and fell in the patient mouth.

Event Description

On november 17, 2020, nakanishi received detailed information from the distributor about the event, including information about the patient.However, the patient id and weight were not included, because the dentist refused to provide it.The details are as follows.The exact date the event occurred is on (b)(6) 2020.During the procedure, the handpiece made an abnormal noise and some internal parts came out.

• 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: 10834194
• MDR Text Key: 216856331
• Report Number: 9611253-2020-00046
• Device Sequence Number: 1
• Product Code: EFB
• Combination Product (y/n): N
• PMA/PMN Number: K113655
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: distributor,foreign
• Type of Report: Initial,Followup
• Report Date: 12/14/2020

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: M800WL
• Device Catalogue Number: P1265
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 10/26/2020
• Initial Date Manufacturer Received: 10/21/2020
• Initial Date FDA Received: 11/13/2020
• Supplement Dates Manufacturer Received: 11/17/2020
• Supplement Dates FDA Received: 12/14/2020
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Other
• Patient Age: 30 YR