MAUDE Adverse Event Report: NAKANISHI INC. FORZA M5; HANDPIECE, CONTRA- AND RIGHT-ANGLE ATTACHMENT, DENTAL

Model Number FORZA M5

Device Problems Component Missing (2306); Detachment of Device or Device Component (2907); Noise, Audible (3273)

Patient Problem Foreign Body In Patient (2687)

Event Date 11/12/2021

Event Type  Injury  

Manufacturer Narrative

The dentist refused to provide the patient's age, weight, ethnicity, and race.

Event Description

On (b)(6) 2021, nakanishi received an email from a distributor ((b)(4)) about a patient's accidental ingestion of a part of a dental device.Details are as follows.The event occurred on (b)(6) 2021.The dentist was performing a root canal procedure on #20 of the patient's tooth and a crown preparation for the tooth using the forza m5 handpiece (serial no.(b)(4)).During the procedure, the dentist heard a noise and noticed that the headcap of the handpiece was missing and could not be located.The dentist thought that the patient either aspirated or swallowed the headcap.The patient was still numb from the dental procedure and was sent to the hospital for x-rays.The x-ray confirmed that the headcap was in the patient stomach.The patient returned to the dental office at a later date to restart the root canal treatment and crown preparation.

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)(6)].These activities are described in more detail below.Methodology used: a) nakanishi examined the device history record and the repair history for the subject forza m5 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 conducted a visual inspection of the outside of the returned device.Nakanishi observed the headcap missing from the handpiece when the device was returned.C) nakanishi disassembled the handpiece and performed a visual inspection of the internal parts.The cardridge and drive shaft were soiled and abraded.Nakanishi took photographs of all the disassembled parts and kept them in investigation report no.(b)(6).D) nakanishi measured the size of the bur used at the time of the event.The maximum diameter of the working portion was 2.5mm in the measurement, which is out of the device specification (2.00mm).E) since there were abnormalities in the headcap and cartridge, nakanishi attached a new headcap and cartridge in inventory and observed whether or not the headcap would loosen by rotating under two different conditions: 1) without load, and 2) with load (cutting a melamine plate at the maximum speed, 200,000min-1).The drive shaft was not replaced because the part was not heavily soiled and abraded.There was no headcap loosening observed in the evaluation.Conclusions reached based on the investigation and analysis results: a) nakanishi could not replicate the reported event.However, nakanishi considers the possibility from many years of experience and based on the findings in the visual inspection, that the headcap was loosened due to a combination of strong impact on the device and vibration during cutting.B) nakanishi also considers the possibility that the use of the out-of-specification bur increased the vibration during cutting, which could be the cause of the headcap loosening, leading to the headcap separation.C) misuse by the user led to the above event, which contributed to the reported accidental ingestion.D) in order to prevent a recurrence of the push button breakage/separation, nakanishi took the following actions: d.1) nakanishi reviewed the operation manual and reconfirmed clarity and understandability of the instructions.D.2) nakanishi reported the above evaluation results to brasseler usa and directed brasseler usa to remind the user of the importance of using the device, as instructed in the operation manual.

• Brand Name: FORZA M5
• 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: 12914040
• MDR Text Key: 281574531
• Report Number: 9611253-2021-00069
• Device Sequence Number: 1
• Product Code: EGS
• Combination Product (y/n): N
• Reporter Country Code: US
• PMA/PMN Number: K182999
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: Distributor
• Reporter Occupation: Dentist
• Type of Report: Initial,Followup
• Report Date: 02/08/2022

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: FORZA M5
• Device Catalogue Number: 5027608U0
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 12/15/2021
• Is the Reporter a Health Professional?: Yes
• Initial Date Manufacturer Received: 11/13/2021
• Initial Date FDA Received: 12/01/2021
• Supplement Dates Manufacturer Received: 01/12/2022
• Supplement Dates FDA Received: 02/08/2022
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 01/22/2020
• 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 Age: 52 YR
• Patient Sex: Male