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 Problem No Clinical Signs, Symptoms or Conditions (4582)

Event Date 06/19/2023

Event Type  malfunction  

Event Description

On june 30, 2023, nakanishi became aware of a malfunction of a nsk handpiece through a complaint input into the complaint database by a distributor (nsk america).Details are as follows: the event occurred on (b)(6) 2023.A dentist was performing a dental procedure on a patient using the z95l handpiece (serial no.(b)(6)).During the procedure, the bur was released from the handpiece and landed at the back of the patient's mouth.The bur was recovered using suction.The patient was under sedation at the time and was unaware of the incident.The patient was unaffected.

Manufacturer Narrative

The same adverse event in this report has been reported to the fda separately by the distributor, nsk america corporation, under report number (b)(4).

Manufacturer Narrative

Upon receiving the device involved in the mdr event from the distributor, nakanishi conducted a failure analysis of the returned device [report no.(b)(4)].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 [dbl20065].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 observed that there were no abnormalities.C) nakanishi measured the burr retention force and observed a value below device specifications.D) nakanishi mounted a company-owned burr to the handpiece and cut a melamine plate while rotating the handpiece to check whether or not the burr would come out of the handpiece.The reported bur loosening was replicated in the device evaluation.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 rear side of the cartridge parts were abraded.The burr-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.(b)(4).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 burr retention force due to the accumulation of debris on the chuck.The accumulation of debris prevented the chuck from maintaining a sufficient burr retention force, which caused the burr slipping during cutting.The burr slipping led to abrasion of the chuck, contributing to the reduced bur retention force.B) a lack of maintenance caused the accumulation of debris on the internal parts, which resulting in the reported event.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 will report the above evaluation results to the distributor and directed the distributor to remind the user of the importance of maintenance as instructed in the operation manual.

• 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: 17358966
• MDR Text Key: 319762411
• Report Number: 9611253-2023-00043
• Device Sequence Number: 1
• Product Code: EGS
• Combination Product (y/n): N
• Reporter Country Code: US
• PMA/PMN Number: K182999
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: Company Representative,Distributor
• Reporter Occupation: Dentist
• Type of Report: Initial,Followup
• Report Date: 09/01/2023

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: Z95L
• Device Catalogue Number: C1034
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Is the Reporter a Health Professional?: Yes
• Initial Date Manufacturer Received: 06/30/2023
• Initial Date FDA Received: 07/20/2023
• Supplement Dates Manufacturer Received: 08/08/2023
• Supplement Dates FDA Received: 08/31/2023
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 02/03/2020
• 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
• Patient Age: 27 YR
• Patient Sex: Male
• Patient Weight: 104 KG
• Patient Ethnicity: Non Hispanic
• Patient Race: White