MAUDE Adverse Event Report: NAKANISHI INC. NSK; HANDPIECE, AIR-POWERED, DENTAL

Model Number S-MAX M500

Device Problems Loose or Intermittent Connection (1371); Detachment of Device or Device Component (2907)

Patient Problem Foreign Body In Patient (2687)

Event Date 12/11/2020

Event Type  Injury  

Manufacturer Narrative

According to the distributor, the detailed information about the event, including information about the patient, was not provided despite the repeated attempts on (b)(6) 2020, (b)(6) 2020, (b)(6) 2021, and (b)(6) 2021.Nakanishi will still try to obtain the information.The same adverse event in this report has been reported to the fda separately by the initial importer, nsk america corporation, under report number (b)(4).

Event Description

On january 8, 2021, nakanishi became aware of a patient's accidental ingestion of a dental bur through a complaint input into the complaint database by a distributor (nsk america).Details are as follows: the event occurred on (b)(6) 2020.A dentist was performing a dental procedure on a patient using the m500l handpiece (serial no.Unknown).During the procedure, the bur came loose from the handpiece and the patient swallowed the bur.

Event Description

On (b)(6) 2021, nakanishi received detailed information on the event from the distributor.At the time of the event, the dentist was performing a restoration procedure on the patient.The patient was under local anesthesia.Since the bur came loose from the handpiece during the procedure, the dentist immediately removed the bur and attached a new one to the same handpiece.The new bur came loose again and dropped into the patient's throat.The patient swallowed the bur.The patient was sent to the emergency room for further evaluation.There were no adverse effects reported from ingestion of the bur and the patient has had a follow-up visit with the doctor.No medical treatment was required for the ingestion.

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 s-max m500 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) nakanishi measured the bur retention force and observed a value below device specifications.C) nakanishi attached a new bur to the handpiece and tried cutting a melamine plate with the device under an air supply pressure of 0.25mpa to observe whether or not the bur would come loose from the chuck.The reported loosening of the bur 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: - there was debris on the chuck.- after removing the debris, abrasion of the bur-holding part of the chuck was observed.B) nakanishi took photographs of all the disassembled parts and kept them in investigation report #(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 bur retention force due to the accumulation of debris on the chuck.The accumulation of debris 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 part, which contributed the bur loosening, 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 will report the above evaluation results to nsk america and direct nsk america to remind the user of the importance of maintenance as instructed in the operation manual.

• Brand Name: NSK
• Type of Device: HANDPIECE, AIR-POWERED, DENTAL
• Manufacturer (Section D): NAKANISHI INC.; 700 shimohinata; kanuma-shi, tochigi-ken 322-8 666; JA 322-8666
• MDR Report Key: 11264129
• MDR Text Key: 230450214
• Report Number: 9611253-2021-00006
• Device Sequence Number: 1
• Product Code: EFB
• Combination Product (y/n): Y
• PMA/PMN Number: K962543
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: company representative
• Type of Report: Initial,Followup
• Report Date: 03/29/2021

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
• Device Operator: Health Professional
• Device Model Number: S-MAX M500
• Device Catalogue Number: P1003
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 03/10/2021
• Initial Date Manufacturer Received: 01/08/2021
• Initial Date FDA Received: 02/01/2021
• Supplement Dates Manufacturer Received: 03/01/2021
• Supplement Dates FDA Received: 03/28/2021
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Other
• Patient Age: 64 YR
• Patient Weight: 68