MAUDE Adverse Event Report: NAKANISHI INC. NSK; HANDPIECE, ROTARY BONE CUTTING

Model Number X-SG65L

Device Problem Overheating of Device (1437)

Patient Problem Burn(s) (1757)

Event Date 02/13/2023

Event Type  Injury  

Manufacturer Narrative

The dentist refused to provide the patient's age and weight.

Event Description

On february 14, 2023, nakanishi received an e-mail from a distributor about an nsk handpiece overheating.According to the distributor, there are two devices suspected to be involved in the event, but the dentist could not identify which one of the devices actually caused the following event.Therefore, nakanishi is submitting two separate mdrs for this event.This mdr is regarding the handpiece with the serial number (b)(4).The event occurred on (b)(6) 2023.A dentist was performing a dental procedure on a patient using the x-sg65l handpiece.During the procedure, the handpiece overheated and burned the patient.

Manufacturer Narrative

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 x-sg65l device [02110148].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 connected the handpiece to the motor and tried to rotate the motor.However, the handpiece was locked and did not rotate at all.Therefore, nakanishi was not able to conduct temperature testing of the device.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 ball bearing on the front side was soiled, discolored, deformed and broken.- the body, chuck and pipe joint were soiled and discolored.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 could not replicate the temperature increase from the event, but based on the findings in the visual inspection, nakanishi determined that the cause of the handpiece overheating was frictional resistance generated by contact between the ball bearing retainer, the outer and inner races, and bearing balls, which was caused by the broken ball bearing.B) nakanishi also considers the possibility from many years of experience, that the cause of the broken ball bearing was the ingress of undesirable materials into the bearing, which interfered with rotation.C) a lack of maintenance caused the accumulation of debris on the internal parts, which contributed to the handpiece overheating.D) in order to prevent a recurrence of the handpiece overheating, nakanishi took the following actions: d.1) nakanishi reviewed the operation manual and reconfirmed the clarity and understandability of the instructions.D.2) nakanishi reported the above evaluation results to the dentist and reminded the dentist of the importance of maintenance and checking of the handpiece prior to use to prevent overheating, as instructed in the operation manual.

• Brand Name: NSK
• Type of Device: HANDPIECE, ROTARY BONE CUTTING
• 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: 16519363
• MDR Text Key: 311044160
• Report Number: 9611253-2023-00015
• Device Sequence Number: 1
• Product Code: KMW
• Combination Product (y/n): N
• Reporter Country Code: JA
• PMA/PMN Number: K970953
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: Company Representative,Distributor
• Reporter Occupation: Non-Healthcare Professional
• Type of Report: Initial,Followup
• Report Date: 04/21/2023

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 03/09/2023
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: X-SG65L
• Device Catalogue Number: H1009
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Manufacturer Received: 03/29/2023
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 01/16/2021
• 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 Sex: Female
• Patient Ethnicity: Non Hispanic
• Patient Race: Asian