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

Model Number X95L

Device Problem Detachment of Device or Device Component (2907)

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

Event Date 10/27/2023

Event Type  Injury  

Manufacturer Narrative

The dentist refused to provide information about the patient's sex and weight.Upon receiving the device involved in the mdr event, 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 x95l device [g2210626].There were no problems observed during manufacturing or testing noted in the dhr.The repair history showed 2 service records since the device was shipped.The repair details are as follows: on (b)(6) 2022: the cartridge, drive shaft, dog clutch, and fiber optic assy were replaced.On (b)(6) 2020: the cartridge was replaced.With respect to the repairs in the above list, the service records indicate that nakanishi performed all of the necessary operation checks and confirmed that all of the criteria were met.B) nakanishi conducted a visual inspection of the returned device and observed that there were no abnormalities.C) nakanishi performed a manual reproducibility test.Nakanishi mounted a bur to the handpiece and locked the chuck.Nakanishi then pulled the bur by hand from the handpiece to check whether or not the bur was removed from the handpiece and observed that the bur was not able to be pulled out of the handpiece.D) nakanishi mounted a bur to the handpiece and cut a melamine plate while rotating the handpiece to check whether or not the bur would come out of the handpiece.The reported bur loosening was not replicated in the device evaluation.E) nakanishi measured the bur pull-out force and observed that the value was within the device specifications (22n or greater).F) nakanishi measured the size of the bur returned together with the handpiece, which was the same type of bur used during the reported event and observed no problems with the size of the bur.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, cut the chuck and performed a visual inspection of the internal parts.Nakanishi observed the following: the cartridge was soiled and abraded.The drive shaft and dog clutch were discolored.The bur-holding part of the chuck was soiled.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) although nakanishi could not replicate the reported event, nakanishi considers the possibility from many years of experience 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 and using the device as instructed in the operation manual.

Event Description

On october 31, 2023, nakanishi received a phone call from a dental office about a patient's accidental ingestion of a dental bur.The details nakanishi obtained are as follows: the event occurred on (b)(6) 2023.A dentist was performing a crown removal procedure on a patient using the x95l handpiece (serial no.(b)(6).During the procedure, the bur came out of the handpiece, and the patient swallowed the bur.When the patient has a follow up visit with the dentist next time, the patient will undergo an x-ray to be safe.According to the dentist, there were no abnormalities observed in the device prior to use.

• 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: 18136683
• MDR Text Key: 328108540
• Report Number: 9611253-2023-00065
• Device Sequence Number: 1
• Product Code: EGS
• Combination Product (y/n): N
• Reporter Country Code: JA
• PMA/PMN Number: K182999
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: Foreign,Health Professional
• Reporter Occupation: Dentist
• Type of Report: Initial
• Report Date: 11/15/2023

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 11/14/2023
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: X95L
• Device Catalogue Number: C600
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 11/02/2023
• Is the Reporter a Health Professional?: Yes
• Date Manufacturer Received: 10/31/2023
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 01/22/2022
• 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: 70 YR
• Patient Ethnicity: Non Hispanic
• Patient Race: Asian