MAUDE Adverse Event Report: NAKANISHI INC. NSK; HANDPIECE, DIRECT DRIVE, AC-POWERED

Model Number ARS-F4R

Device Problems Break (1069); Detachment Of Device Component (1104); Component Falling (1105); Detachment of Device or Device Component (2907)

Patient Problems Choking (2464); Blood Loss (2597); Foreign Body In Patient (2687)

Event Date 05/17/2016

Event Type  Injury  

Event Description

On (b)(6) 2016, nakanishi received a phone call from a distributor saying that a brush had come off of the handpiece and a patient had accidentally swallowed it.Details are as follows : the event occurred on (b)(6) 2016.A dental hygienist was cleaning the tooth surface of a patient with a 2-piece device of ars-f4r (serial no.(b)(4)) and taskal wizard motor (serial no.(b)(4)).During the procedure, the patient bled, then the hygienist tried to remove the blood through a suction tube.In the blood removal process, the patient choked, and the hygienist stopped the procedure.The hygienist found that a brush attached to the ars-f4r disappeared.The patient swallowed the brush and the brush reached the digestive system.The patient was not anesthetized.The patient went through an x-ray at a clinic and the doctor tried to take the brush out from the patient's stomach with an endoscope.Due to the brush not being removed, the doctor prescribed a drug that increases excretion.On may 25, 2016, nakanishi received the information that the brush was excreted from the patient's body on (b)(6) 2016.

Manufacturer Narrative

Upon receiving the device involved in the mdr event from a distributor, (b)(4) conducted a failure analysis of the returned device [(b)(4)].These activities are described in more detail below.Methodology used: (b)(4) examined the device history record and the repair history for the subject ars-f4r device [serial number (b)(4)].There were no problems observed during the manufacturing or testing noted in the dhr.The repair history showed one service record (february 2015) since the device was shipped.(b)(4) then connected the ars-f4r to a taskal wizard motor and rotated the motor to observe the rotational condition.(b)(4) confirmed bur run-out in the observation.(b)(4) disassembled the contra-angle head and performed a visual inspection of the inside parts.(b)(4)observed the following phenomena: ingress and accumulation of paste in the head.Abrasion of the end cap metal (shaft retainer).Space of an engagement part between the rotary shaft and the shaft retainer (b)(4) took photographs of all of the disassembled parts and kept them in a file.(b)(4) performed a reproducibility evaluation under the following conditions to explore the possibility of the brush loosening/coming off.Direction: forward rotation; forward rotation; reverse rotation; reverse rotation; load: unloaded; loaded; unloaded; loaded; min: 30 min; 30 min; 30 min; 30 min.Rotation speed: head: 2500rpm, motor : 10,000rpm; 2500rpm, motor : 10,000rpm; head : 2500rpm, motor : 10,000rpm; 2500rpm, motor: 10,000rpm.Under condition (b)(4) observed that the brush started to loosen and then came off.There was no abnormal operation of the motor handpiece such as unintentional switching of the rotation direction during the evaluation.Conclusions reached based on the investigation and analysis results: from the results of the above evaluations, (b)(4) considers the possible cause of the reported brush coming off was the reverse rotation of the brush during operation.The reverse rotation was likely caused by accidentally pressing the reverse switch, leading to rotation in the opposite direction thus loosening the screw.Misuse by the user causes the reverse rotation, which causes the brush to loosen during rotation.This contributes to the brush coming off.In order to prevent a recurrence of the brush coming off, (b)(4) reported the above evaluation to the dentist and gave the dentist a warning about the reverse rotation.

• Brand Name: NSK
• Type of Device: HANDPIECE, DIRECT DRIVE, AC-POWERED
• 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 ; 1201 richardson dr.; suite 160; richardson, TX 75080 ; 9724809554
• MDR Report Key: 5722736
• MDR Text Key: 47313020
• Report Number: 9611253-2016-00028
• Device Sequence Number: 1
• Product Code: EKX
• Combination Product (y/n): N
• Reporter Country Code: JA
• PMA/PMN Number: K990682
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: distributor,foreign
• Reporter Occupation: Other
• Type of Report: Initial,Followup
• Report Date: 11/22/2016

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 06/14/2016
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Dental Hygienist
• Device Model Number: ARS-F4R
• Device Catalogue Number: Y110017
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 05/23/2016
• Is the Reporter a Health Professional?: No
• Date Manufacturer Received: 05/18/2016
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 10/29/2013
• 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: 82 YR
• Patient Weight: 60