MAUDE Adverse Event Report: NAKANISHI INC. NSK; SCALER, ULTRASONIC

Model Number S970L

Device Problem Detachment of Device or Device Component (2907)

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

Event Date 12/21/2020

Event Type  malfunction  

Manufacturer Narrative

This event occurred in (b)(6), but similar products are marketed in the us under (b)(4).Upon receiving the device involved in the mdr event from the oem, nakanishi conducted a failure analysis of the returned device [ (b)(4)].These activities are described in more detail below.Methodology used: nakanishi examined the device history record and the repair history for the subject z970l device [serial number (b)(4)].There were no problems observed during the manufacturing or testing noted in the dhr.The repair history showed 1 service record (october 2019) since the device was shipped.According to the service record, after repairing the handpiece (replacement of cartridge), nakanishi performed all of the necessary operation checks and confirmed that all of the criteria were met.Nakanishi conducted a visual inspection of the returned device and observed no o-ring on the joint.Since there was no o-ring, nakanishi considered the possibility that the malfunction was caused due to the o-ring being caught on the tapering.Therefore, nakanishi performed a manual reproducibility test in the following manner.Nakanishi attached an o-ring to the joint and observed the device.There was no gap between the coupling and the handpiece.Nakanishi then supplied the handpiece with air at the manufacturer's recommended pressure (0.3mpa) and pulled the handpiece by hand to see whether or not the handpiece would detach from the coupling.Nakanishi did not observe the handpiece detaching as reported by the user.Nakanishi performed the same test using the handpiece without the o-ring.Nakanishi observed a gap in the handpiece and the handpiece detaching from the coupling.Nakanishi evaluated pull strength of the handpiece by pulling the handpiece from the coupling using force specified in the specifications (100n) after placing o-rings in designated places.The handpiece did not separate from the coupling.Nakanishi measured the dimension of the coupler insert, and there was no abnormality in the size.Conclusions reached based on the investigation and analysis results: nakanishi identified the cause of the handpiece separation was an unstable connection between the handpiece and the coupling due to the o-ring missing from the joint.A lack of maintenance caused the o-ring to separate from the joint during use.In addition, failure to check the handpiece before use led to the user being unaware of the unstable connection of the devices caused by the joint without the o-ring, which led to the reported event.In order to prevent a recurrence of the device separation, nakanishi took the following actions: nakanishi reviewed the operation manual and reconfirmed clarity and understandability of the instructions.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 the reported phenomenon, as instructed in the operation manual.

Event Description

On january 6, 2021, an nsk s970l handpiece was returned from an oem to nakanishi for repair.There was a note with the device stating that the device had malfunctioned.The details are as follows: the event occurred on (b)(6) 2020.A dentist was performing a dental procedure using the s970l handpiece (serial no.(b)(4)).During the procedure, the handpiece came out of the coupling and came into contact with the patient.No injury occurred to the patient.

• Brand Name: NSK
• Type of Device: SCALER, ULTRASONIC
• 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: kenneth block ; 800 e campbell rd.; suite 202; richardson, TX 75081 ; 9724809554
• MDR Report Key: 11256793
• MDR Text Key: 243687286
• Report Number: 9611253-2021-00005
• Device Sequence Number: 1
• Product Code: ELC
• Combination Product (y/n): N
• Reporter Country Code: JA
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: foreign,other
• Reporter Occupation: Non-Healthcare Professional
• Type of Report: Initial
• Report Date: 02/01/2021

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: S970L
• Device Catalogue Number: T1005
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 01/06/2021
• Initial Date Manufacturer Received: 01/06/2021
• Initial Date FDA Received: 01/31/2021
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 07/24/2017
• 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