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 08/12/2022

Event Type  Injury  

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 (b)(4) 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 first patient.Details are as follows: the event occurred on (b)(6) 2022.The hygienist at the location reported that a patient had received an electric shock from the va-lux-hp handpiece (serial no.(b)(4)).The patient described intense pain when the foot pedal was activated to begin the cleaning procedure.The scaling tip had not yet contacted the buccal surface of #18 tooth when the patient stopped the hygienist complaining of intense pain.The hygienist stopped and talked with the patient letting them know that the scaling tip had not even contacted his tooth only the water coming from the tip.After waiting for a few minutes, the patient recovered.The hygienist turned the scaling unit off, unplugged it, and then plugged the unit back in and turned it on again.After a discussion with the patient about how strange the situation was and restating that the scaler had not even contacted his tooth only the water, the hygienist and the patient agreed to continue the procedure.Once the hygienist pressed the foot pedal to begin the procedure and the water started, before the scaler tip contacted the tooth, the patient claimed again to have felt an electric shock.It was at that time that the hygienist put the unit out of service and the procedure was finished manually.The patient has reported to the dentist to have experienced ongoing pain and numbness near the affected area.The latest report from the patient stated that the pain was subsiding but still has a numb/deadened strip from the tip to the back of their tongue although this does not seem to have any effect on their sense of taste.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

The same adverse event in this report has been reported to the fda separately by the distributor, (b)(4), under report number 1422375-2022-00036.

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 va-lux-hp device (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 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: 15466779
• MDR Text Key: 300436354
• Report Number: 9611253-2022-00065
• 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): Hospitalization; Other
• Patient Age: 63 YR
• Patient Sex: Male
• Patient Weight: 73 KG
• Patient Ethnicity: Non Hispanic
• Patient Race: White