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

Model Number Z800L

Device Problems Detachment of Device or Device Component (2907); Temperature Problem (3022)

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

Event Date 07/12/2022

Event Type  malfunction  

Event Description

On july 13, 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.The dentist was performing a dental procedure on a patient using the z800l handpiece (serial no.(b)(4).During the procedure, the headcap of the handpiece came off unexpectedly, and some internal parts landed in the patient's mouth.The parts were recovered, and there was no affect 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 1422375-2022-00029.

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: a) nakanishi examined the device history record and the repair history for the subject z800l device [(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) nakanishi conducted a visual inspection of the returned device and observed the following: - the headcap and the cartridge were separated from the device.- the bearing of the cartridge rear side was disassembled.- there were no abrasion or deterioration of the headcap thread and head thread.C) nakanishi measured the size of the bur returned with the cartridge.The length of the bur was 21.50mm in the measurement, which is out of the device specification (21.00mm).Nakanishi also found the working portion was abraded.C) nakanishi mounted a new cartridge to the head of the handpiece and cut a melamine plate while rotating the handpiece under no load at the maximum speed (440,000min-1) to check whether or not the headcap would loosen.The reported loosening of the headcap was not replicated in the device evaluation.D) nakanishi took photographs of all the disassembled parts and kept them in the investigation report no.(b)(4).Conclusions reached based on the investigation and analysis results: a) although nakanishi could not replicate the reported event, nakanishi considers the possibility from similar event that nsk has experienced in the past, the combination of the reduced headcap tightening force together with abnormal vibration, which caused by use of the out-of-specification bur, could result in the reported headcap loosening/separation.B) misuse by the user led to the above issue, which contributed to the reported event.C) in order to prevent a recurrence of the headcap loosening/separation, nakanishi took the following actions: c.1) nakanishi reviewed the operation manual and reconfirmed the clarity and understandability of the instructions.C.2) 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, AIR-POWERED, 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: 15154469
• MDR Text Key: 297177781
• Report Number: 9611253-2022-00054
• Device Sequence Number: 1
• Product Code: EFB
• Combination Product (y/n): N
• Reporter Country Code: US
• PMA/PMN Number: K113655
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: Company Representative,Distributor
• Reporter Occupation: Dentist
• Type of Report: Initial,Followup
• Report Date: 09/12/2022

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 08/03/2022
• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: Z800L
• Device Catalogue Number: P1110
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Is the Reporter a Health Professional?: Yes
• Date Manufacturer Received: 09/02/2022
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 03/27/2017
• Is the Device Single Use?: No
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Other