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

Model Number TI-MAX X450KL

Device Problems Air Leak (1008); Leak/Splash (1354); Mechanical Problem (1384); Device Issue (2379); Computer Operating System Problem (2898); Physical Property Issue (3008)

Patient Problems Pulmonary Emphysema (1832); Swelling (2091); Patient Problem/Medical Problem (2688)

Event Date 03/28/2016

Event Type  Injury  

Manufacturer Narrative

(b)(4).

Event Description

On april 26, 2016, nakanishi received an e-mail from a distributor ((b)(4)) about the nsk handpiece problem.Details received from the distributor are as follows.On april 18, 2016, (b)(4) was made aware by incoming repair paperwork that hot air had occasionally come out from the front side of the nsk handpiece, ti-max x450kl (serial no: (b)(4)), which resulted in a patient's injury during a tooth extraction.On the same day (april 18, 2016), (b)(4) made a phone call to advise the dentist that there was no problem found with the handpiece in the (b)(4)'s testing evaluation and the handpiece had passed all manufacturer specifications inspection standards.In the telephone conversation, the dentist described the event that only air (without water) had come out of the handpiece head when the dentist started the handpiece, which had made the patient's cheek swollen and the extraction procedure had not been started.The dentist did not provide any more information in the conversation, but agreed to complete (b)(4)'s information form.On april 22, 2016, (b)(4) received further information about the event as follows.The event occurred on (b)(6) 2016.The procedure the dentist was performing is an extraction of tooth #32.The patient's cheek was swollen before the extraction started.The patient was not under sedation/anesthesia.An emphysema was developed on right side of patient's face all the way to the eye.No treatment was administered by the dentist.The patient was referred to an oral surgeon.The patient went to the oral surgeon and will not have any follow-up with the oral surgeon.

Manufacturer Narrative

The problem with the returned device is air occasionally comes out of the front of the handpiece, but it is not hot air as was described in nakanishi's initial report.Patient information: despite the efforts (b)(4) (distributor) made that were described in the initial report, nakanishi did not receive any information about the patient weight.Upon receiving the device involved in the mdr event from a distributor, nakanishi conducted a failure analysis of the returned device.These activities are described in more detail below.Methodology used: nakanishi examined the device history record and the repair history for the subject ti-max x450kl device [serial number (b)(4)].There were no problems observed during the manufacturing or testing noted in the dhr.There were also no repair history records since the device was shipped.Nakanishi conducted a visual inspection of the returned device and observed no visible abnormalities, such as cracks or dents, on the outside of the handpiece.Then, nakanishi performed an operation check in accordance with product inspection standard (pc-001168).Nakanishi confirmed that all specifications in the standard were satisfied in the evaluation.Nakanishi carried out a reproducibility evaluation as follows.From the dentist's complaint that the handpiece and coupling did not work properly and that a problem was caused during a dental procedure due to air occasionally coming out of the front of the handpiece, nakanishi considered the possibility of sealing failure of the o-ring between the coupling and the handpiece.Therefore, nakanishi intentionally removed the o-ring between the irrigation circuit and the air chip circuit of a company-owned coupling to observe the irrigation condition.The reason why the company-owned coupling was used in the evaluation is because the coupling involved in the event was not returned to nakanishi from the distributor.Nakanishi observed that when the air chip pressure was higher than the water supply pressure, air came out of the front of the handpiece with no water, because the chip air enters into the irrigation circuit.Conclusions reached based on the investigation and analysis results: nakanishi identified that the cause of the air coming out of the front of the returned handpiece was sealing failure of the o-ring of the coupling due to damage to or breakage of the o-ring.The sealing failed to block airflow, which let air go into the irrigation circuit, leading to the air coming out of the device.Since the o-ring is a consumable item, nakanishi determined that a lack of maintenance caused damage to/breakage of the o-ring, which contributed to the reported problem.In order to prevent a recurrence of the air coming out, nakanishi took the following actions: nakanishi reviewed the operation manual and reconfirmed that the instructions on when and how to change the o-ring were included.Nakanishi also reconfirmed clarity and understandability of the instructions.Nakanishi reported the above evaluation results to nsk america and directed the distributor to remind the user of the importance of following the operation manual.

Manufacturer Narrative

On october 14, 2016, nakanishi heard from the distributor that no additional information regarding the patient was available.

• 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
• MDR Report Key: 5669231
• MDR Text Key: 45614667
• Report Number: 9611253-2016-00025
• Device Sequence Number: 1
• Product Code: EFB
• Combination Product (y/n): N
• PMA/PMN Number: K112024
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: company representative
• Type of Report: Initial,Followup,Followup
• Report Date: 04/26/2016,07/03/2018

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: Dentist
• Device Model Number: TI-MAX X450KL
• Device Catalogue Number: P1079
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 05/10/2016
• Was the Report Sent to FDA?: No
• Distributor Facility Aware Date: 04/18/2016
• Device Age: 2 YR
• Event Location: Other
• Date Report to Manufacturer: 04/26/2016
• Initial Date Manufacturer Received: 04/26/2016
• Initial Date FDA Received: 05/20/2016
• Supplement Dates Manufacturer Received: Not provided; 10/14/2016
• Supplement Dates FDA Received: 11/09/2016; 07/03/2018
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Other
• Patient Age: 42 YR