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

Model Number Z800KL

Device Problem Detachment of Device or Device Component (2907)

Patient Problem No Clinical Signs, Symptoms or Conditions (4582)

Event Date 07/31/2023

Event Type  malfunction  

Manufacturer Narrative

The same adverse event in this report has been reported to the fda separately by the distributor, (b)(4) under report number 1422375-2023-00024.

Event Description

On (b)(6) 2023, nakanishi became aware of a malfunction of a nsk handpiece through a complaint input into the complaint database by a distributor (b)(4).Details are as follows: - the event occurred on (b)(6) 2023.- a dentist was performing a crown preparation procedure on a patient using the z800kl handpiece (serial no.(b)(6) - after ten minutes of using the handpiece, the dentist heard a screeching metal noise and saw that the head cap and turbine missing from the head of the handpiece.- the patient was choked and came up from supine to a 90-degree upright position and spit out the head cap and turbine from their mouth.- after examining the patient's soft palate, the dentist noted some slight bleeding.- the bleeding was stopped, and the procedure was completed with a different handpiece.- the patient was discharged without need for any additional medical treatment.

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 (b)(4) device [0be80086].There were no problems observed during manufacturing or testing noted in the dhr.There were no records indicating nakanishi (the manufacturer) repaired the device since the device was shipped.Nakanishi received the repair record from nsk america (the distributor), which included the detailed information about the repair nsk america carried out.Nakanishi kept the repair record in a file.B) nakanishi conducted an operation check of the returned device and observed the following: no-load rotation speed was 391,000min, which met nakanishi's specification (360,000 - 420,000min-1).Abnormal noise was observed during rotation.C) nakanishi rotated the handpiece under no load and cut a melamine plate while rotating the handpiece at the maximum speed (420,000min-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 disassembled the handpiece and conducted a visual inspection of the internal parts.Nakanishi observed the following: there were no abrasion or deterioration of the headcap thread and head thread.The inside of the head was soiled and discolored.There were contact marks on the rotor of the cartridge, which was deformed.E) 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 observed that the rotor of the cartridge was deformed and the inside of the head was soiled, which caused abnormal noise, run-out, and abnormal vibration.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 high-load cutting, run-out of the bur, or 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 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
• 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: 17658929
• MDR Text Key: 322375792
• Report Number: 9611253-2023-00053
• 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: 11/15/2023

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 08/31/2023
• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: Z800KL
• Device Catalogue Number: P1112
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Is the Reporter a Health Professional?: Yes
• Date Manufacturer Received: 10/27/2023
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 09/03/2014
• 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
• Patient Age: 56 YR
• Patient Sex: Male
• Patient Weight: 70 KG
• Patient Ethnicity: Non Hispanic
• Patient Race: White