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

Model Number Z900KL

Device Problem Detachment of Device or Device Component (2907)

Patient Problem Unspecified Tissue Injury (4559)

Event Date 08/20/2020

Event Type  Injury  

Manufacturer Narrative

Nakanishi did not receive any information about the patient, and will try to obtain the information during a visit to the dentist scheduled on (b)(6) 2020.Upon receiving the device involved in the mdr event, nakanishi conducted a failure analysis of the returned device [report no.C200824-04].These activities are described in more detail below.Methodology used: nakanishi examined the device history record and the repair history for the subject z900kl device [serial no.(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.Nakanishi conducted a visual inspection of the returned device and observed that the cartridge and headcap separated from the device, the cartridge bearing broke apart, and the bur fractured.Nakanishi, then 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.After replacing the broken cartridge with a new cartridge and setting the returned headcap in the handpiece, nakanishi observed whether or not the headcap would loosen by rotating without load and then cutting a melamine plate at the maximum speed (400,000min-1).There was no headcap loosening observed in the evaluation.Conclusions reached based on the investigation and analysis results: nakanishi could not replicate the headcap separation at the time of the event, however based on the abnormality of the inside parts observed in the visual inspection, as well as many years of experience, nakanishi determined that the cause of the reported separation was abnormal vibration generated by contact between the headcap and the cartridge, which was caused by the headcap being pressed down during rotation.In addition, some strong impact on the device or repeated cutting vibration may also have contributed to the headcap loosening.Misuse by the user leads to the contact between the headcap and the cartridge, which contributes to the headcap separation, leading to the reported injury.In order to prevent a recurrence of the patient's injury, 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 dentist and remind the dentist of the importance of using the device as instructed in the operation manual.

Event Description

On august 20, 2020, nakanishi received a phone call from a dealer about a patient injury caused by an nsk handpiece.The information nakanishi obtained from the communication is as follows: the event occurred on (b)(6) 2020.The dentist was removing a eugenol-based endodontic sealer from the patient tooth using the z900kl handpiece (serial no.(b)(4)).During the procedure, the headcap separated from the head, the cartridge came out, and the patient was injured by the cartridge.A follow-up with the patient is scheduled.

• 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: kenneth block ; 800 e campbell rd.; suite 202; richardson, TX 75081 ; 9724809554
• MDR Report Key: 10526745
• MDR Text Key: 207024303
• Report Number: 9611253-2020-00035
• Device Sequence Number: 1
• Product Code: EGS
• Combination Product (y/n): N
• Reporter Country Code: JA
• PMA/PMN Number: K113655
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: foreign,other
• Reporter Occupation: Non-Healthcare Professional
• Type of Report: Initial
• Report Date: 09/14/2020

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: Z900KL
• Device Catalogue Number: P1113
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 08/24/2020
• Initial Date Manufacturer Received: 08/20/2020
• Initial Date FDA Received: 09/14/2020
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 02/28/2017
• 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