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

Model Number	SGA-E2S
Medical Device Problem Code	Overheating of Device (1437)
Health Effect - Clinical Code	Burn(s) (1757)
Date of Event	12/01/2025
Type of Reportable Event	Serious Injury
Additional Manufacturer Narrative
The distributor was unable to provide any further information about the event, including information about the patient, because they had received the incident information through a government technology center and therefore had no direct contact.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 sga-e2s device [serial no.(b)(6).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) since the handpiece was returned from the distributor in pieces, 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 performed a visual inspection of the disassembled internal parts of the handpiece and observed that the bearing was 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 identified that the cause of the handpiece overheating was abnormal resistance during rotation due to the soiled bearing.B) nakanishi considers the possibility from many years of experience that the cause of the soiled bearing was the ingress of undesirable materials into the bearing, leading to abrasion.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 distributor and directed the distributor to remind the user of the importance of maintenance, as instructed in the operation manual.
Event or Problem Description
On december 22, 2025, nakanishi became aware of a handpiece overheating through a complaint input into the complaint database by a distributor (b)(4).The details are as follows: the event occurred on december 1, 2025.The dentist was performing a dental procedure on a patient using the sga-e2s handpiece (serial no.(b)(6).During the procedure, the handpiece overheated, and the patient received a burn injury.

• Brand Name: NSK
• Common Device Name: 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: 24112018
• Report Number: 9611253-2026-00002
• Device Sequence Number: 10400256
• Product Code: KMW
• UDI-Device Identifier: 04560225001214
• UDI-Public: (01)04560225001214
• Combination Product (Y/N): N
• Initial Reporter Country: AS
• PMA/510(K) Number: K171155
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Serviced by Third Party (Y/N): N
• Reporter Type: Manufacturer
• Report Source: Foreign,Distributor
• Initial Reporter Occupation: Non-Healthcare Professional
• Remedial Action: Recall
• Type of Report: Initial
• Report Date (Section B): 01/20/2026

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Operator of Device: Health Professional
• Device Model Number: SGA-E2S
• Device Catalogue Number: H265
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 12/25/2025
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 12/22/2025
• Initial Report FDA Received Date: 01/19/2026
• Was Device Evaluated by Manufacturer? (Y/N): Yes
• Date Device Manufactured: 05/27/2021
• Is the Device Labeled for Single Use? (Y/N): No
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Usage of Device: Reuse
• If action reported to FDA under 21 USC 360i(g), list FDA-assigned Recall Number or include a statement: 9611253-060818-001-R
• Patient Sequence Number: 1
• Outcome Attributed to Adverse Event: Other
• Patient Sex: Unknown