MAUDE Adverse Event Report: NAKANISHI, INC. (NSK) DA-355

Model Number DA-355

Device Problem Detachment Of Device Component (1104)

Patient Problems Foreign Body In Patient (2687); No Known Impact Or Consequence To Patient (2692)

Event Date 01/11/2013

Event Type  Injury  

Event Description

This mdr is being reported at this time as part of our internal review of past complaints and service records.Due to the incident being in the past, we are limited in the info that we can obtain from the initial complainant.Event summary: according to the dentist, a bur was detached from a handpiece during a treatment and the pt accidentally swallowed the bur.This pt visited a hosp and the bur was observed in the body by an x-ray examination.According to the info obtained by the dist on (b)(6) 2013, the doctor told the pt to let the bur go out naturally and continue observing the physical condition.Complaint review: there is no complaint review for this handpiece.

Manufacturer Narrative

Investigation: the handpiece was forwarded to the mfr (nakanishi) for an analysis and investigation on 1/25/2013.As of this report, no additional info has been received.Upon receipt from the dentist of the device involved in the mdr event, nakanishi conducted a failure analysis of the returned device that included an attempt to measure the retention force of the operating device ((b)(4)).These activities are described in more detail below: methodology used: nakanishi examined the returned products including the bur used, ss white carbide bur (b)(4), whose acceptance rotation speed is 300,000 or less.This bur was used with nmc-su03 cartridge that generates a rotation speed higher that 300,000.Nakanishi examined the device history records for the subject nmc-su03 cartridge (serial number (b)(4)).There were no problems observed during the mfg or testing noted in the dhr.Nakanishi conducted a visual inspection of the returned device and performed a simple movement test.There were no visible abnormalities, such as cracks or debris, on the outside of the handpiece.Nakanishi conducted retention force measurement by setting a test bur in the handpiece and confirmed it was 6.3n.Nakanishi's acceptance criteria for the retention force is 14.7n or above, indicating that the retention force of the subject handpiece had deteriorated.Nakanishi disassembled the handpiece to observe the inside of the chuck.Nakanishi confirmed accumulated dirt on the inner periphery and the pin sliding surface of the chuck, whose images were captured with photographs.Nakanishi cleaned the chuck and took photographs of the cleaned parts of the chuck.Nakanishi reassembled the handpiece and measured the retention force again and confirmed it was 18.1n which is higher than nakanishi's acceptance criteria (14.7n or above).Conclusions reached: accumulation of dirt inside the chuck caused the deterioration of the retention force of the chuck that caused the detachment of the bur.Insufficient cleaning maintenance by the user caused the accumulation of the dirt.Additionally, the user used a bur which is not specified for the use with the subject handpiece.Nakanishi provided the user instruction regarding the appropriate type of bur and cleaning maintenance to be used in a report dated (b)(6) 2013.This event occurred in (b)(6), but similar products are marketed in the us under (b)(4).

• Brand Name: DA-355
• Manufacturer (Section D): NAKANISHI, INC. (NSK); 700 shimohinata; kanuma-shi, tochigi-ken 322- 8666; JA 322-8666
• Manufacturer (Section G): NAKANISHI INC. (NSK); 700 shimohinata; kanuma-shi, tochigi-ken 322- 8666; JA 322-8666
• Manufacturer Contact: ken block ; 1201 richardson dr.; ste 280; richardson, TX 75080 ; 9724809554
• MDR Report Key: 4740223
• MDR Text Key: 16852466
• Report Number: 9611253-2015-00037
• Device Sequence Number: 1
• Product Code: EFB
• 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
• Reporter Occupation: Service Personnel
• Type of Report: Initial
• Report Date: 04/20/2015

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?: No
• Device Operator: Health Professional
• Device Model Number: DA-355
• Device Catalogue Number: P620002
• Was Device Available for Evaluation?: Yes
• Date Returned to Manufacturer: 01/25/2013
• Is the Reporter a Health Professional?: No
• Initial Date Manufacturer Received: 01/25/2013
• Initial Date FDA Received: 04/28/2015
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 09/01/2010
• Is This a Reprocessed and Reused Single-Use Device?: No
• Type of Device Usage: Reuse
• Patient Sequence Number: 1
• Patient Outcome(s): Other