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

Model Number VA2-LUX-HP

Device Problems Overheating of Device (1437); Temperature Problem (3022)

Patient Problems Burn(s) (1757); Skin Discoloration (2074); Injury (2348); Burn, Thermal (2530); Patient Problem/Medical Problem (2688)

Event Date 03/25/2020

Event Type  Injury  

Manufacturer Narrative

The dentist refused to disclose the patient id, age, and weight.This event occurred in (b)(6), but similar products are marketed in the us under k113530.

Event Description

On (b)(6) 2020, nakanishi received an e-mail from an oem about an nsk handpiece overheating.The information nakanishi obtained from the communication is as follows: the event occurred on (b)(6) 2020.A dentist was performing a dental procedure on a patient using the va2-lux hp (serial no.: (b)(4).The patient was not under anesthesia.During the procedure, the tip attached to the handpiece overheated and burned the patient's lip.The burned area was discolored.The dentist reported that the tip used along with the handpiece was not an nsk genuine tip.No medical treatment was required for the injury.

Manufacturer Narrative

Upon receiving the device involved in the mdr event from the oem, nakanishi conducted a failure analysis of the returned device that included measuring the operating temperature of the 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 va2-lux-hp 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 checked the characteristics of the returned handpiece (resonance frequency and impedance), but no abnormalities were observed during the inspection.C) nakanishi found that the shape of the tip returned with the handpiece was different from the original nsk tip, and that "pn3 152" was marked on the tip.This indicates that a competitor tip was used with the handpiece at the time of the event.D) nakanishi conducted temperature testing of the returned device in the following manner: d.1) nakanishi attached an nsk g6 tip and the returned pn3 tip to the device and observed whether or not the reported overheating would be reproduced with the robot arm movement under the following conditions, exceeding normal use: - power level setting: general 8 (maximum allowable output) - water supply volume: 5ml/min - cutting pressure: 1.2n (relatively strong pressure on teeth) - cutting object: melamine plate (as an alternative to teeth) - evaluation period: twenty seconds.D.2) nakanishi measured the temperature rise of 2 test points on the tip (point proximal to the cutting area (tooth) and point distal to the cutting area) using a thermography camera.However, the temperatures were not high enough to cause a burn injury.Temperature measurements observed during the test were as follows: - during movement of the robot arm test point a: 30.5 degrees c, test point b: 31.7 degrees c test point a: 32.2 degrees c, test point b: 31.8 degrees c - after movement of the robot arm test point a: 30.5 degrees c, test point b: 30.5 degrees c test point a: 32.2 degrees c, test point b: 31.7 degrees c.Conclusions reached based on the investigation and analysis results: a) nakanishi could not identify the exact cause of overheating of the returned device because nakanishi was not able to replicate the temperature rise at the time of the event.However, nakanishi confirmed that a non-nsk tip had been used during the dental procedure, which is prohibited by the manufacturer.B) use of the out-of-specification tip increases the probability of overheating, which could be the cause of the patient burn injury.C) in order to prevent a recurrence of the handpiece overheating, nakanishi took the following actions: c.1) nakanishi reviewed the operation manual and reconfirmed the warning to use only nsk genuine tips.C.2) nakanishi will report the above evaluation results to the oem and direct the oem to remind the dentist of the importance of using the device 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
• MDR Report Key: 9970631
• MDR Text Key: 194139492
• Report Number: 9611253-2020-00020
• Device Sequence Number: 1
• Product Code: ELC
• Combination Product (y/n): N
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: other
• Type of Report: Initial,Followup
• Report Date: 05/18/2020

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: VA2-LUX-HP
• Device Catalogue Number: E351050
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 04/03/2020
• Initial Date Manufacturer Received: 03/27/2020
• Initial Date FDA Received: 04/16/2020
• Supplement Dates Manufacturer Received: 04/17/2020
• Supplement Dates FDA Received: 05/18/2020
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Other