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

Model Number Z45L

Device Problems Overheating of Device (1437); Material Separation (1562); Detachment of Device or Device Component (2907)

Patient Problems Foreign Body In Patient (2687); No Clinical Signs, Symptoms or Conditions (4582)

Event Date 05/27/2022

Event Type  malfunction  

Event Description

On (b)(6) 2022, nakanishi became aware of a handpiece overheating through a complaint input into the complaint database by a distributor ((b)(4)).Details are as follows: the event occurred on (b)(6) 2022.A dentist was performing a dental procedure using the z45l handpiece (serial no.(b)(4)).The head of the handpiece separated from the body during the procedure while inside the patient's mouth.There was no injury to the patient.

Manufacturer Narrative

The same adverse event in this report has been reported to the fda separately by the distributor, (b)(4) , under report number 1422375-2022-00025.

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: nakanishi examined the device history record and the repair history for the subject z45l device [02160038].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.Nakanishi conducted a visual inspection of the returned device and observed a gap between the head assembly and the body.Nakanishi disassembled the handpiece and performed a visual inspection of the internal parts.Nakanishi observed the following: the drive shaft retainer was loose and the head was removed easily.The head cap and bearing of the rear side were abraded.Nakanishi took photographs of all the disassembled parts and kept them in the investigation report no.(b)(4).Nakanishi reassembled the handpiece and observed no gap between the head and the body of the device.Nakanishi then conducted temperature testing of the device in the following manner: 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.Nakanishi attached a thermocouple (sensor to measure temperature) to each of the testing points.Nakanishi rotated the device's motor at 40,000min-1, which is the maximum rpm for the motor that drives the handpiece (168,000min-1 for the handpiece), with water spray, and measured the exothermic response.Nakanishi measured the temperature rise of the returned handpiece set at 168,000min-1 (motor revolution 40,000min-1).Nakanishi observed no abnormal temperature rise at the test points during the planned 5-mimute evaluation period.Conclusions reached based on the investigation and analysis results: nakanishi did not identify the exact cause, but nakanishi considers the possibility from many years of experience, the combination of a strong impact on the device together with cutting vibration could result in the reported head loosening/separation.In order to prevent a recurrence of the head loosening/separation, nakanishi took the following actions: nakanishi reviewed the operation manual and reconfirmed the clarity and understandability of the instructions.Nakanishi will report the above evaluation results to the distributor and directed the distributor to remind the user of the importance of maintenance as instructed in the operation manual.

• Brand Name: NSK
• 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: sean kaufman ; 1800 global parkway; hoffman estates, IL 60192 ; 2245128921
• MDR Report Key: 14795943
• MDR Text Key: 295145847
• Report Number: 9611253-2022-00038
• Device Sequence Number: 1
• Product Code: EGS
• Combination Product (y/n): N
• Reporter Country Code: US
• PMA/PMN Number: K121901
• 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: 08/24/2022

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 06/23/2022
• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: Z45L
• Device Catalogue Number: C1064
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 06/17/2022
• Is the Reporter a Health Professional?: Yes
• Date Manufacturer Received: 08/05/2022
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 06/23/2021
• 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