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

Model Number Z800L

Device Problems Mechanical Problem (1384); Device Slipped (1584); Detachment of Device or Device Component (2907)

Patient Problems Foreign Body In Patient (2687); Patient Problem/Medical Problem (2688)

Event Date 02/20/2020

Event Type  Injury  

Manufacturer Narrative

According to the distributor, the dentist refused to provide the patient's weight.

Event Description

On april 7, 2020, nakanishi became aware of a patient's accidental ingestion of a dental bur through a complaint input into the complaint database by a distributor (nsk america).Details are as follows: the event occurred on (b)(6) 2020.A dentist was removing a dental crown from the patient's tooth (#15) using the z800l handpiece (serial no.(b)(4)).During the procedure, the bur came loose from the chuck and the patient accidentally swallowed the bur.Routine x-rays have been taken to monitor progress through the gastro-intestinal tract and ensure excretion.The dentist determined that no further medical treatment was required.

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 [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 measured the bur retention force and observed a value below company criteria.C) nakanishi tried cutting a melamine plate and a copper plate with air supply pressure of 0.28mpa to observe whether or not the bur would come loose from the chuck.The reported bur coming out was replicated in the observation.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 the following phenomena: there was debris on the chuck.After removing the debris, abrasion of the bur-holding part in the chuck was observed.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 identified that the cause of the bur coming out of the returned device was a decrease in bur retention force due to the accumulation of debris on the chuck.The accumulation of debris prevented the chuck from maintaining sufficient bur retention force, which led to the bur coming out during the treatment on the patient.B) a lack of maintenance caused the accumulation of debris on the internal part, which contributed the reported bur coming out.C) in order to prevent a recurrence of the bur coming out, nakanishi took the following actions: c.1) nakanishi reviewed the operation manual and reconfirmed the clarity and understandability of the instructions.C.2) nakanishi reported the above evaluation results to nsk america and directed nsk america 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
• MDR Report Key: 10008334
• MDR Text Key: 191977824
• Report Number: 9611253-2020-00022
• Device Sequence Number: 1
• Product Code: EFB
• Combination Product (y/n): N
• PMA/PMN Number: K113655
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: company representative
• Type of Report: Initial,Followup
• Report Date: 05/22/2020

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 04/29/2020
• Is this an Adverse Event Report?: Yes
• 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
• Date Returned to Manufacturer: 04/15/2020
• Date Manufacturer Received: 04/29/2020
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Other
• Patient Age: 68 YR