MAUDE Adverse Event Report: NAKANISHI INC. NSK; CONTROLLER, FOOT, HANDPIECE AND CORD

Model Number UM500SB

Device Problems Bent (1059); Use of Device Problem (1670); Device Operates Differently Than Expected (2913); Human Factors Issue (2948)

Patient Problems Injury (2348); Patient Problem/Medical Problem (2688)

Event Date 11/26/2016

Event Type  Injury  

Manufacturer Narrative

This event occurred in (b)(6) on a product for laboratory use, but similar products are marketed in the us under (b)(4).

Event Description

On (b)(6) 2016, an nsk laboratory product um500sb (a4317074) was returned to nakanishi from a distributor for repair.There was a note with product stating that the device had malfunctioned and a dentist was injured.The details are as follows.The event occurred on (b)(6) 2016.When the dentist stepped lightly on the foot pedal during use, the motor rotated at a high speed and bent the bur.The dentist's fingernail on his right hand was injured.The dentist was treated at a hospital emergency department immediately.According to the dentist, the dentist used a low speed setting, but the dentist did not remember the set rotation speed.The dentist was using a mandrel bur for paper cone.The dentist is currently treating patients with a finger splint.

Manufacturer Narrative

Upon receiving the device involved in the adverse event, nakanishi conducted a failure analysis of the returned device.Methodology used: nakanishi examined the device history record for the subject um500sb device (a4317074).There were no problems observed during the manufacturing or testing noted in the dhr.Nakanishi conducted a visual inspection of the returned device and performed a simple movement test.- nakanishi set a test bur in the handpiece.Nakanishi observed that the bur did not go into the handpiece completely as compared to the normal state.Handpiece chuck check - nakanishi removed a chuck from the handpiece.- nakanishi checked inside the chuck and observed the accumulation of dirt/foreign materials.- nakanishi cleaned the dirt inside chuck, then nakanishi observed that the bur could be inserted to the normal position.- nakanishi measured the bur retention force using a test bur.Nakanishi confirmed that the retention force was 7.1kg which indicates a decrease in retention force as the nakanishi standard value is 8.0kg or greater.Rotational check - nakanishi checked that reproducibility with and without cutting load for each rotational speed (1,000rpm/5,000rpm,/10,000rpm/15,000rpm/20,000rpm/25,000rpm/30,000rpm/40,000rpm) using the returned device.- nakanishi did not observe reproducibility of an event which changes rotational speed higher than the set values during operation.Control unit pc board check - nakanishi examined the control pc board and an abnormal state leading to malfunction was not observed.- nakanishi confirmed that the control pc board was normal.Foot pedal overhauls - nakanishi disassembled the foot pedal and performed a visual inspection of parts.- nakanishi did not observe any damage or accumulation of dirt/foreign materials inside the foot pedal.- nakanishi confirmed that the foot pedal was normal.- nakanishi took photographs of all of the disassembled parts and kept them in a file.Conclusion reached based on the investigation and analysis result.- nakanishi concluded that the accumulation of dirt/foreign materials caused the deterioration of retention force of chuck that caused the bur bent during the operation.In order to prevent a recurrence of the accumulation of the dirt inside the chuck, nakanishi took the following actions: nakanishi reviewed the operation manual and clarity and understandability of the instructions.A lack of the maintenance causes the accumulation of dirt (abrasive powders/foreign materials) in the inside the parts.Nakanishi reported the above evaluation results to the dentist and reminded the dentist of the importance of maintenance (cleaning) as instructed in the operation manual.The distributor did not disclose the patient's age or weight.

• Brand Name: NSK
• Type of Device: CONTROLLER, FOOT, HANDPIECE AND CORD
• 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 ; 9724809552
• MDR Report Key: 6240984
• MDR Text Key: 64507096
• Report Number: 9611253-2017-00001
• Device Sequence Number: 1
• Product Code: EBW
• Combination Product (y/n): N
• Reporter Country Code: JA
• 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: 05/26/2017

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 01/11/2017
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Dentist
• Device Model Number: UM500SB
• Device Catalogue Number: U384002
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 12/02/2016
• Is the Reporter a Health Professional?: No
• Date Manufacturer Received: 01/16/2017
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 08/09/2004
• 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