MAUDE Adverse Event Report: NAKANISHI INC. FORZA F5; HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL

Model Number FORZA F5

Device Problems Overheating of Device (1437); Device Operates Differently Than Expected (2913); Temperature Problem (3022)

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

Event Date 03/15/2018

Event Type  Injury  

Manufacturer Narrative

Nakanishi tried to obtain further information about the patient and the event in the communication with the distributor on (b)(6) 2018.According to the distributor, despite of the repeated attempts to contact the dentist, the dentist did not disclose the information.

Event Description

On (b)(6) 2018, nakanishi received an email from a distributor ((b)(6) usa) stating that an nsk dental handpiece had overheated and burned two patients.Therefore, nakanishi is submitting two separate mdrs for the two patients.The information about the first patient is as follows.The exact date when the event occurred is unknown.The date entered indicates the best estimate.A dentist was performing a dental procedure using the forza f5 (serial no.(b)(4)).During the procedure, the handpiece overheated and burned the patient.

Manufacturer Narrative

Upon receiving the device involved in the mdr event from a distributor, nakanishi conducted a failure analysis of the returned device that included measuring the operating temperature of the device (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 forza f5 device [serial (b)(4)].There were no problems observed during the manufacturing or testing noted in the dhr.There were also no repair history records since the device was shipped.B) nakanishi conducted temperature testing of the returned device in the following manner: b.1) temperature sensors were attached to the exterior of the device at various test points.This included the point most proximal to the patient (testing point (1)) and points further toward the distal end of the device (testing points (2) through (4)).The test setup was prepared to take temperature measurements at all points simultaneously, including a reference measurement at ambient room temperature.B.2) nakanishi attached a thermocouple (sensor to measure a temperature) to each of the testing points.Nakanishi rotated the device's motor at 40,000 min-1, which is the maximum rpm for the motor that drives the handpiece (200,000 min-1 for the handpiece), with water spray, and measured the exothermic response.B.3) nakanishi measured the temperature rise of the returned handpiece set at 200,000 min-1 (motor revolution 40,000 min-1).Nakanishi observed the temperature at the testing points during the 300-second test period; however, there was no abnormal rise in temperature.The following shows the temperature at the testing points at the end of the test period.Test point (1): 30.5 degrees c, test point (2): 32.3 degrees c, test point (3): 29.1 degrees c, test point (4): 30.0 degrees c.Identification of the specific failure mode(s) and/or mechanism(s) and the associated device components involved: a) nakanishi disassembled the handpiece and performed a visual inspection of the inside parts.Nakanishi did not observe any abnormalities.B) nakanishi took photographs of all of the disassembled parts and kept them in the investigation report (b)(4).Conclusions reached based on the investigation and analysis results: 1) 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 and did not observe any abnormalities in the visual inspection.2) in spite of the fact that nakanishi did not identify the cause, nakanishi took the following actions to be safe.2.1) nakanishi reviewed the operation manual and reconfirmed the clarity and understandability of the instructions.2.2) nakanishi reported the above evaluation results to brasseler usa and reminded brasseler usa of the importance of maintenance, as instructed in the operation manual.

• Brand Name: FORZA F5
• Type of Device: HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL
• 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: 7506114
• MDR Text Key: 107976165
• Report Number: 9611253-2018-00018
• Device Sequence Number: 1
• Product Code: EGS
• Combination Product (y/n): N
• Reporter Country Code: US
• PMA/PMN Number: K972569
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: health professional,other
• Reporter Occupation: Dentist
• Type of Report: Initial,Followup
• Report Date: 06/21/2018

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 05/11/2018
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Dentist
• Device Model Number: FORZA F5
• Device Catalogue Number: 5021285U0
• Was Device Available for Evaluation?: No
• Is the Reporter a Health Professional?: Yes
• Was the Report Sent to FDA?: No
• Date Manufacturer Received: 05/30/2018
• Was Device Evaluated by Manufacturer?: Device Not Returned to Manufacturer
• Date Device Manufactured: 04/27/2016
• 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