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

Model Number S-MAX M600L

Device Problems Detachment Of Device Component (1104); Mechanical Problem (1384); Sticking (1597); Detachment of Device or Device Component (2907)

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

Event Date 02/24/2016

Event Type  Injury  

Manufacturer Narrative

On (b)(6) 2016, the day when nakanishi visited the hospital and gained some patient information, nakanishi also tried to obtain the patient identifier and weight from the dentist, however the dentist refused to provide the information.

Event Description

On (b)(6) 2016, nakanishi received a phone call from a distributor about an nsk dental product.Upon receipt of the information, nakanishi visited the hospital to hear the details from the dentist.The details are as follows.On (b)(6) 2016, a dentist was cutting the back tooth of the upper right jaw using nsk s-max m600l.The patient was not anesthetized.During the procedure, a bur fixed to the handpiece suddenly came off as if slipping.The patient got the bur stuck in the throat.The patient underwent a computed tomography scan and have the bur removed through an endoscope procedure.

Manufacturer Narrative

Upon receipt from the distributor of the device involved in the mdr event, nakanishi conducted a failure analysis of the returned device [(b)(4)].These activities are described in more detail below.Methodology used : nakanishi examined the device history record for the subject s-max m600l device [serial number (b)(4)].There were no problems observed during the manufacturing or testing noted in the dhr.Nakanishi measured the bur retention force using a test bur (1.598mm in diameter).Nakanishi confirmed that the retention force was 12.5n which indicates a decrease in retention force as the nakanishi standard value is 14.7n or greater.Nakanishi disassembled the handpiece and performed a visual inspection of the inside parts.Nakanishi observed dirt on the sliding surface of the chuck pin in the cartridge.Nakanishi took photographs of the inside parts observed in the visual inspection and kept them in a file.Nakanishi conducted a visual inspection of the returned bur and observed scratches on the bur surface.The places that the scratches were observed on the bur are in alignment with the places nakanishi observed dirt in the above evaluation.Nakanishi also took photographs of the scratched bur and kept them in a file.Conclusions reached based on the investigation and analysis results : nakanishi identified that the cause of the bur coming off was due to chuck abrasion and application of overload to the bur.Bur retention force is decreased by the use of a worn chuck, which leads to the bur coming off when the overload is applied.Also, dirt ingress into the chuck prevents the intended bur retention force from being achieved.This will contribute to the bur coming off.In order to prevent a recurrence of the bur coming off, nakanishi took the following actions : nakanishi reviewed the operation manual and reconfirmed clarity and understandability of the instructions.Nakanishi reported the above evaluation results to the dentist and reminded the dentist of the importance of periodical cleaning of the chuck 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
• Manufacturer (Section G): NAKANISHI INC.; 700 shimohinata; kanuma-shi, tochigi-ken 322-8 666; JA 322-8666
• Manufacturer Contact: ken block ; 1201 richardson dr.; suite 160; richardson, TX 75080 ; 9724809544
• MDR Report Key: 5519227
• MDR Text Key: 40933625
• Report Number: 9611253-2016-00010
• Device Sequence Number: 1
• Product Code: EFB
• Combination Product (y/n): N
• Reporter Country Code: JA
• PMA/PMN Number: K962543
• 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: 06/02/2016

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 03/23/2016
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Dentist
• Device Model Number: S-MAX M600L
• Device Catalogue Number: P1002
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 03/14/2016
• Is the Reporter a Health Professional?: No
• Date Manufacturer Received: 02/26/2016
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 03/31/2011
• 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: 18 YR