MAUDE Adverse Event Report: NAKANISHI INC. NSK; HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL

Model Number Z95L

Device Problem Detachment of Device or Device Component (2907)

Patient Problems Foreign Body In Patient (2687); No Clinical Signs, Symptoms or Conditions (4582)

Event Date 09/13/2022

Event Type  Injury  

Manufacturer Narrative

The dentist refused to provide any information about the patient.Upon receiving the device involved in the mdr event, nakanishi conducted a failure analysis of the returned device [report no.C220921-06].These activities are described in more detail below.Methodology used: a) nakanishi examined the device history record and the repair history for the subject z95l device [cbj60381].There were no problems observed during manufacturing or testing noted in the dhr.There were no repair history records since the device was shipped.B) nakanishi measured the bur retention force and observed a value below device specifications.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: the cartridge, headcap, drive shaft, and dog clutch were soiled, discolored, and abraded.The bur-holding part of the chuck was soiled and abraded.B) nakanishi took photographs of all the disassembled parts and kept them in the investigation report no.C220921-06.Conclusions reached based on the investigation and analysis results: a) nakanishi identified that the cause of the bur loosening in the returned device was a decrease in bur retention force due to the high-load cutting and accumulation of debris on the chuck.The accumulation of debris and high-load cutting prevented the chuck from maintaining a sufficient bur retention force, which led to the bur loosening during the treatment on the patient.B) a lack of maintenance caused the accumulation of debris on the internal parts, and misuse by the user contributed the bur loosening, which resulting in the reported accidental ingestion.C) in order to prevent a recurrence of the bur loosening, 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 maintenance as instructed in the operation manual.

Event Description

On september 21, 2022, a nsk z95l handpiece was returned from a dealer to nakanishi for repair.There was a note with the device stating that a patient accidentally ingested a bur coming off out of the device.Upon receipt of the information, nakanishi made a phone call to a hospital for further information about the event including information about the patient.The details nakanishi obtained are as follows.The event occurred on (b)(6) 2022.The dentist was performing a bridge cutting procedure on the patient using the z95l handpiece (serial no.(b)(4)).During the procedure, the bur came off in the patient's mouth, and the patient swallowed the bur.The bur did not enter the lungs of the patient, and the bur was recovered from the stomach by use of an endoscope.It was reported that the patient had a follow-up visit and no additional medical treatment was required.The dentist found that the chuck of the handpiece was slightly loose prior to use, however the bur was locked in the handpiece after the dentist removed the bur and inserted it back.

• Brand Name: NSK
• Type of Device: HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL
• Manufacturer (Section D): NAKANISHI INC.; 700 shimohinata; kanuma-shi, tochigi-ken 322-8 666; JA 322-8666
• Manufacturer (Section G): NAKANISHI INC.; 700 shimohinata; kanuma-shi, tochigi-ken 322-8 666; JA 322-8666
• Manufacturer Contact: sean kaufman ; 1800 global parkway; hoffman estates, IL 60192 ; 2245128921
• MDR Report Key: 15613185
• MDR Text Key: 301820246
• Report Number: 9611253-2022-00075
• Device Sequence Number: 1
• Product Code: EGS
• Combination Product (y/n): N
• Reporter Country Code: JA
• PMA/PMN Number: K972569
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: Other,Foreign
• Reporter Occupation: Non-Healthcare Professional
• Type of Report: Initial
• Report Date: 10/17/2022

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 10/16/2022
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: Z95L
• Device Catalogue Number: C1034
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 09/22/2022
• Date Manufacturer Received: 09/21/2022
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 06/08/2018
• Is the Device Single Use?: No
• Is This a Reprocessed and Reused Single-Use Device?: No
• Type of Device Usage: Reuse
• Patient Sequence Number: 1
• Patient Outcome(s): Other