MAUDE Adverse Event Report: NAKANISHI INC. NSK; HANDPIECE, AIR-POWERED, DENTAL

Model Number TI-MAX X450YL

Device Problems Use of Device Problem (1670); Adverse Event Without Identified Device or Use Problem (2993); Device Handling Problem (3265)

Patient Problems Hemorrhage/Bleeding (1888); Injury (2348); Patient Problem/Medical Problem (2688)

Event Date 01/20/2020

Event Type  Injury  

Manufacturer Narrative

Nakanishi did not receive any information about the patient, but is scheduled to visit the dentist to obtain the information.This event occurred in (b)(6), but similar products are marketed in the us under k112024.

Event Description

On january 20, 2020, nakanishi received a phone call from a dealer about an injury caused by an nsk handpiece.The information nakanishi obtained from the communication is as follows: the event occurred on (b)(6) 2020.A dentist was extracting the patient's #8 tooth using the ti-max x450yl handpiece (serial no.(b)(4)).During the procedure, the dentist found bleeding from an injury on the mucosa of the patient's cheek.

Manufacturer Narrative

The dentist refused to provide the patient id and weight when the dealer visited the hospital on (b)(6) 2020.Upon receiving the device involved in the mdr event, nakanishi conducted a failure analysis of the returned device that included measuring the operating temperature of the device [c200120-05].These activities are described in more detail below.Methodology used: a) nakanishi examined the device history record and the repair history for the subject ti-max x450yl 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 conducted temperature testing of the returned device in the following manner: b.1) temperature sensors were attached to the exterior of the handpiece head at 2 test points.This included the side of the head (testing point (1) and push button of the head (testing points (2).The test setup was prepared to take temperature measurements at both points simultaneously, including a reference measurement at ambient room temperature.B.2) nakanishi attached a thermocouple (sensor to measure temperature) to both of the testing points.Nakanishi rotated the handpiece at 0.22mpa, which is the maximum air pressure for the device, with water spray, and measured the exothermic response.B.3) nakanishi measured the temperature rise of the returned handpiece set at 0.22 mpa under normal use and with the push button remaining pressed.The temperatures nakanishi observed during the 300-second-test period are as follows.Temperatures under normal use: test point (1): 26.0 degrees c, test point (2): 26.7 degrees c, temperatures with the push button remaining pressed, test point (1): 21.7 degrees c, test point (2): 70.7 degrees c.Nakanishi did not observe temperatures high enough to cause a burn injury under normal use condition, however nakanishi confirmed abnormal temperatures of the handpiece with the push button remaining pressed.Identification of the specific failure mode(s) and/or mechanism(s) of the associated device components was conducted as follows: a) nakanishi disassembled the handpiece and performed a visual inspection of the internal parts.Nakanishi observed contact traces on the surfaces of the cartridge and headcap caused by a push button being pressed.B) nakanishi took photographs of all of the disassembled parts and kept them in investigation report#: (b)(4).Conclusions reached based on the investigation and analysis results: a) nakanishi could not observe the abnormal temperature rise when the device was operated under normal use, however the abnormal temperature was confirmed when the device was used with the push button being pressed.Since nakanishi found the contact traces on the internal parts in the visual inspection, nakanishi identified that the cause of the patient's injury was the handpiece overheating due to frictional heat generated by contact between the headcap and the cartridge, which was caused by the headcap being pressed during rotation, or the patient's buccal mucous membrane being caught between the button and the cap when the push button was depressed.B) misuse by the user leads to the contact between the headcap and the cartridge, which contributes to the reported injury.C) in order to prevent a recurrence of the patient's injury, nakanishi took the following actions: c.1) nakanishi reviewed the operation manual and reconfirmed clarity and understandability of the instructions.C.2) nakanishi reported the above evaluation results to the dentist and reminded the dentist of the importance of using the device as instructed in the operation manual.

• Brand Name: NSK
• Type of Device: HANDPIECE, AIR-POWERED, DENTAL
• Manufacturer (Section D): NAKANISHI INC.; 700 shimohinata; kanuma-shi, tochigi-ken 322-8 666; JA 322-8666
• MDR Report Key: 9691406
• MDR Text Key: 188811742
• Report Number: 9611253-2020-00003
• Device Sequence Number: 1
• Product Code: EFB
• Combination Product (y/n): N
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: foreign,other
• Type of Report: Initial,Followup
• Report Date: 02/24/2020

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 02/11/2020
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: TI-MAX X450YL
• Device Catalogue Number: P1085
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 01/21/2020
• Date Manufacturer Received: 01/30/2020
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Other
• Patient Age: 20 YR