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

Model Number TI-MAX X450 5H

Device Problems Break (1069); Material Separation (1562); Detachment of Device or Device Component (2907); Noise, Audible (3273)

Patient Problems Foreign Body In Patient (2687); No Clinical Signs, Symptoms or Conditions (4582)

Event Date 12/16/2020

Event Type  malfunction  

Manufacturer Narrative

Nakanishi is trying to obtain information about the patient.The same adverse event in this report has been reported to the fda separately by the initial importer, (b)(4), under report number (b)(4).

Event Description

On december 21, 2020, nakanishi became aware of a malfunction of an 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) 2020.A dentist was performing a crown procedure using the ti-max x450 5h handpiece (serial no.(b)(4)).During the procedure, the device made a popping noise and the head of the handpiece came off in the patient's mouth.The glass rod broke and metal pieces fell into the patient's mouth.The dentist removed the pieces and there was no effect on the patient.The patient had a follow up visit with the dentist on (b)(4) 2020, and the patient has had no complications and does not require any medical treatment.

Manufacturer Narrative

On may 26, 2021, nakanishi received an email from the distributor (nam) stating that nam could not receive information about the patient despite the following attempts.- on january 18, 2021, nam received a voicemail message from the office stating that they did not see the point in providing the information.- on february 3, 2021, nam placed a follow up call and left a voicemail message requesting the office to return the call.- on march 25, 2021, nam made the third call and sent another email request.

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 ti-max x450 5h 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 conducted a visual inspection of the returned device and observed that the head assembly, body, and fiber optic rod were separated from the device.Nakanishi also confirmed that the fiber optic rod and head retainer were broken.C) nakanishi disassembled the handpiece and performed a visual inspection of the internal parts.Nakanishi observed dents and scratches on the head.D) nakanishi performed a reproducibility test to see how the reported breakage of the head retainer occurred.3 handpieces were used in the test.D.1) nakanishi tied the heads to a push-pull gauge with string and gradually pulled the push-pull gauge up to a maximum load of 500n, parallel to the necks, to see whether or not there would be a gap between the heads and the bodies.Nakanishi observed that no gap was created.D.2) nakanishi then attached the handpieces to a torque meter and turned the necks clockwise with a wrench to evaluate the torque value when the heads loosen.Nakanishi confirmed that the head retainers and heads loosened at about 200n of force, but the head retainers never broke during the evaluation.However, nakanishi observed a different failure from the reported one, which was twisted circuits in the handpieces.Conclusions reached based on the investigation and analysis results: a) since nakanishi confirmed in the above evaluation that head retainers did not break and head separation did not occur unless an extremely strong impact was applied to the device, nakanishi determined that the cause of the event was that the user applied a strong impact on the device leading to the broken head retainer, which resulted in the head separation.B) in order to prevent a recurrence of the reported event, nakanishi took the following actions: b.1) nakanishi reviewed the operation manual and reconfirmed the clarity and understandability of the instructions.B.2) nakanishi reported the above evaluation results to nsk america and directed nsk america to remind the user of the importance of using the device 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: 11184028
• MDR Text Key: 245730953
• Report Number: 9611253-2021-00003
• Device Sequence Number: 1
• Product Code: EFB
• Combination Product (y/n): N
• PMA/PMN Number: K112024
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: company representative
• Type of Report: Initial,Followup,Followup
• Report Date: 06/22/2021

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: TI-MAX X450 5H
• Device Catalogue Number: P1093
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 01/08/2021
• Initial Date Manufacturer Received: 12/21/2020
• Initial Date FDA Received: 01/18/2021
• Supplement Dates Manufacturer Received: 04/29/2021; 05/26/2021
• Supplement Dates FDA Received: 05/26/2021; 06/21/2021
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Other