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

Model Number VA-LUX-HP

Device Problem Unintended Electrical Shock (4018)

Patient Problem Numbness (2415)

Event Date 04/01/2022

Event Type  Injury  

Manufacturer Narrative

The same adverse event in this report has been reported to the fda separately by the distributor, nsk america corporation, under report number 1422375-2022-00037.The hygienist did not record which of their patients this happened to because this event occurred approximately four months ago.

Event Description

On september 2, 2022, nakanishi received fda notification of a voluntary report made by a patient (mdr report# mw5111578).Nakanishi contacted a distributor (nsk america) to obtain detailed information.According to the information, two patients were involved with the device.Therefore, nakanishi is submitting two separate mdrs for the two patients.This mdr is regarding the second patient.Details are as follows: the event occurred on (b)(6) 2022.The patient described feeling a shock from the va-lux-hp handpiece (serial no.(b)(4) at the beginning of a cleaning procedure when the scaler handpiece was activated, and water began.The scaler tip had not yet contacted the tooth surface only the water when the patient reported feeling the shock.The hygienist attributed the patient's feeling of electric shock to the temperature of the water, and the cleaning procedure was continued by the hygienist normally without any further issues.The device model in the voluntary report made by the patient (varios 370) was found to be incorrect the unit is in fact a varios 350 lux.

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.C220903-01].These activities are described in more detail below.Methodology used: a) nakanishi examined the device history record and the repair history for the subject va-lux-hp device [dbe50226].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 handpiece and the va350 lux control unit, the hose, and the foot pedal, which were returned together with the handpiece, and observed the following: the light in the handpiece did not turn on.The hose connector in the handpiece was corroded.The hose jacket of the handpiece and the cord jacket of the foot peal were broken, but they are not disconnected.C) nakanishi measured insulation resistance of the handpiece in the following manner.C.1) alligator clips were attached to the exterior of the handpiece at 3 testing points.This included the point most proximal to the patient and points further toward the distal end of the handpiece.C 2) nakanishi attached an insulation resistance meter to each of the testing points.Nakanishi connected the handpiece to the control unit and measured the insulation resistance value.C 3) nakanishi observed no abnormal value between the handpiece and the control unit.D) nakanishi measured leakage current of the control unit under the following condition in accordance with ansi/aami es60601-1.Input voltage: 132v (120vx110%) 60hz protection against electric shock class: class-ii operation mode of va350 lux control unit: g mode max tip attached to handpiece: g8 nakanishi observed that the measured leakage current was within the specifications.E) nakanishi conducted a dielectric strength test of the control unit under the following condition in accordance with ansi/aami es60601-1.Applying ac500v between the secondary transformer and ap (the end of the tip attached to the handpiece).Applying ac4000v between l/n (the power cord) and ap temperature: 24.7 degrees celsius, humidity: 64.4% nakanishi observed that the current value on each of the measuring points were within the specifications.F) nakanishi took photographs of all the measurements and the test and kept them in the investigation report no.(b)(4).Conclusions reached based on the investigation and analysis results: a) nakanishi could not identify the exact cause of the electrical shock from the returned handpiece because nakanishi was not able to replicate the electrical shock at the time of the event and did not observe any abnormalities leading to the electrical shock in the visual inspection, the measurements, and the test above.B) in spite of the fact that nakanishi could not identify the cause, nakanishi took the following actions to be safe: 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 the distributor and directed the distributor to remind the user of the importance of using the device and maintenance as instructed in the operation manual.

• 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: sean kaufman ; 1800 global parkway; hoffman estates, IL 60192 ; 2245128921
• MDR Report Key: 15466836
• MDR Text Key: 300420624
• Report Number: 9611253-2022-00066
• Device Sequence Number: 1
• Product Code: ELC
• Combination Product (y/n): N
• Reporter Country Code: US
• PMA/PMN Number: K031421
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: Company Representative,Distributor
• Reporter Occupation: Other Health Care Professional
• Type of Report: Initial,Followup
• Report Date: 11/28/2022

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: VA-LUX-HP
• Device Catalogue Number: E250050
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Is the Reporter a Health Professional?: Yes
• Initial Date Manufacturer Received: 09/02/2022
• Initial Date FDA Received: 09/22/2022
• Supplement Dates Manufacturer Received: 11/07/2022
• Supplement Dates FDA Received: 11/27/2022
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 05/26/2014
• 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