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

Model Number VA2-HP

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

Patient Problems Burn(s) (1757); Injury (2348); Patient Problem/Medical Problem (2688)

Event Date 04/10/2020

Event Type  Injury  

Manufacturer Narrative

The dentist refused to provide any information about the patient.This event occurred in (b)(6), but similar products are marketed in the us under k113530.Upon receiving the device involved in the mdr event from the oem, (b)(6) 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) (b)(6) examined the device history record and the repair history for the subject va2-hp device [serial no.(b)(4)].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) (b)(6) checked the characteristics of the returned handpiece (resonance frequency and impedance), but no abnormalities were observed during the inspection.C) (b)(6) conducted temperature testing of the returned device in the following manner: c.1) (b)(6) attached a g6 tip (the highest-selling nsk tip) to the device and observed whether or not the reported overheating would be reproduced with the robot arm movement under the conditions of: - 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.C.2) (b)(6) 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: 30.9 degrees c, test point b: 33.1 degrees c - after movement of the robot arm test point a: 30.4 degrees c, test point b: 32.8 degrees c c.3) (b)(6) then altered the test conditions to observe the exothermic response with the robot arm movement in a different circumstance.- power level setting: general 8 (maximum allowable output).- water supply volume: 5ml/min.- cutting pressure: 4.5n (relatively strong pressure on skin).- cutting object: silicone (as an alternative to skin).- evaluation period: ten seconds.C.4) test point b of the tip was pressed against the silicone during rotation for 10 seconds to measure the temperature on the surface of the silicone.(b)(6) confirmed an abnormal temperature of 55 degrees c under these conditions.Conclusions reached based on the investigation and analysis results: a) (b)(6) identified that the cause of the reported burn injury was friction heat generated by contact between the patient's skin and the tip during rotation.B) misuse by the user caused the above situation, which contributed to the patient burn injury.C) in order to prevent a recurrence of the handpiece overheating, (b)(6) took the following actions: c.(b)(6) reviewed the operation manual and reconfirmed clarity and understandability of the instructions.C.(b)(6) 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.

Event Description

On (b)(6) 2020, (b)(6) received an e-mail from an oem about an nsk handpiece overheating.The information (b)(6) obtained from the communication is as follows: the event occurred on (b)(6) 2020.A dental hygienist was performing a dental procedure on a patient using the va2-hp handpiece (serial no.(b)(4) with water spray.During the procedure, the dental hygienist found a burn injury with blisters in the patient's mouth, caused by contact with the tip of the handpiece.

• 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 ; 4809554
• MDR Report Key: 10008376
• MDR Text Key: 191579861
• Report Number: 9611253-2020-00023
• 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: 04/29/2020

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-HP
• Device Catalogue Number: E350052
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 04/10/2020
• Initial Date Manufacturer Received: 04/10/2020
• Initial Date FDA Received: 04/29/2020
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 03/31/2016
• 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