Using a syringe needle to cut dentin and dislodge and remove a metallic obstruction from the root canal.

A metallic obstruction in the canal orifice of a maxillary right canine could not be bypassed during endodontic treatment. Aids such as ultrasonics and retrieval kits were not available for the removal of the obstruction. Therefore, a novel approach using a disposable syringe needle was employed. A 22-gauge needle was inserted into the orifice and turned in an arc with a gentle apical pressure and alternate rocking motion around the obstruction. This procedure was repeated few times to cut dentin and successfully dislodge and remove the obstruction using the sharp beveled tip of the needle. This case report demonstrates that, in the absence of other aids, the use of a disposable syringe needle is a simple, economical, and yet an effective technique for conservative removal of dentin and to dislodge and remove an obstruction from the root canal. However, its effectiveness depends on case selection and straight-line accessibility to the obstruction.

INTRODUCTION

Metallic obstructions such as broken burs, separated instruments, needles, and pins inside the root canal require bypassing or retrieval for successful endodontic treatment.[12] Retrieval should be attempted when they cannot be bypassed and it depends on form, friction, and site of the obstruction.[1]

Grasping instruments, retrieval kits, and ultrasonics are used for the retrieval of metallic obstructions.[123] Interestingly, the potential for the use of a luer-lock type hypodermic needle, due to the presence of a lumen with a sharp beveled edge, to cut dentin and retrieve a foreign object has also been mentioned.[4] However, such a procedure is rarely reported. Moreover, the use of a hypodermic needle to dislodge a metallic obstruction from the root canal is not reported in the literature. This presentation illustrates the use of a disposable syringe needle to cut dentin in a conservative manner and to dislodge and remove a metallic obstruction from the root canal.

CASE REPORT

A 35-year-old female was reported for endodontic treatment in the maxillary right canine. She mentioned that root canal treatment was initiated in this tooth and the treatment was incomplete. The radiographic examination of tooth revealed a periapical radiolucency and an access restoration with a metallic obstruction, approximately 1.5 mm in length, lodged in the root canal orifice [Figure 1a]. The initial instrumentation to access the obstruction was misdirected and led to gouging of the pulp chamber, and the tightly wedged obstruction could not be bypassed [Figure 1b]. Therefore, a decision was taken to remove the obstruction. However, aids such as magnification devices, ultrasonics, and retrieval kits were not available to the clinician for the removal of the obstruction. Therefore, considering gouging and small size of the obstruction and to avoid excessive removal of dentin, a simple and novel approach of using a disposable syringe needle (Unolock, Hindustan Syringes & Medical Devices Ltd., Ballabgarh, Faridabad, Haryana, India) was employed to cut dentin and to dislodge and remove the obstruction from the canal.

Figure 1

(a) Preoperative radiograph showing a metallic obstruction (white arrow) in the canal orifice of maxillary right canine with a periapical radiolucency. (b) Radiograph showing gouged pulp chamber of tooth with the metallic obstruction which could not be bypassed. (c) Clinical image of a 22-gauge disposable syringe needle with a sharp beveled tip (white arrow). (d) Clinical image showing the use of syringe needle in tooth to remove dentin and dislodge the obstruction. (e) Radiograph taken to monitor the procedure

A 22-gauge needle (0.70 mm in diameter, 25 mm in length) with a sharp beveled tip was selected [Figure 1c]. This needle was selected after superimposing different gauge needles over the obstruction on the radiograph. The needle was introduced into the canal orifice and turned in an arc gently but with firm apical pressure to remove dentin around the obstruction using its sharp beveled tip [Figure 1d]. The needle was retracted from the canal. Any dentin debris clogging the needle lumen was cleared off. The needle tip was inspected for any bend or dulling. A needle with bent or dull tip was discarded and another similar gauge needle was employed. The needle was reinserted into the canal and turned in an arc with gentle apical pressure. This procedure was repeated few times to conservatively remove the dentin around the obstruction and was radiographically monitored [Figure 1e]. The removal of dentin with alternate working of the needle alongside the obstruction in a rocking motion loosened and dislodged the obstruction. The dislodged obstruction was recovered from the pulp chamber. The obstruction was found to be a fragment of an endodontic file [Figure 2a]. A radiograph was taken to confirm the removal of the obstruction from the canal orifice [Figure 2b]. The canal was negotiated, and working length was determined using apex locator (Propex, Dentsply Maillefer, Switzerland) and confirmed with a radiograph. The canal was cleaned and shaped using a step-back technique. The canal was irrigated with 2.5% sodium hypochlorite between instrumentation and finally flushed with 17% ethylenediaminetetraacetic acid solution to remove smear layer. Calcium hydroxide (Calcicur, VOCO, Cuxhaven, Germany) was used as an intracanal medicament. In the subsequent visit, the canal was obturated with gutta-percha points (Dentsply Maillefer, Ballaigues, Switzerland) and sealer (AH Plus, Dentsply Maillefer, Ballaigues, Switzerland) using lateral compaction technique [Figure 2c]. The access opening was restored with composite resin (Filtek Z350 XT, 3M ESPE, St. Paul, MN, USA). At 6-month follow-up visit, tooth was found asymptomatic with radiographically satisfactory and progressive healing of the periapical lesion [Figure 2d].

Figure 2

(a) Clinical image showing the needle along with the metallic obstruction (white arrow) dislodged and removed from the canal orifice. (b) Radiographic confirmation of removal of the obstruction from the canal orifice. (c) Postobturation radiograph of tooth. (d) Six-month follow-up radiograph of asymptomatic tooth showing satisfactory and progressive healing of the periapical lesion

DISCUSSION

In the present case, the use of disposable syringe needle was successful as the obstruction was small and was coronally situated at level of canal orifice. The syringe needle was effective in both cutting the dentin and dislodging the obstruction. A syringe needle has the potential to act as a hand drill and cut dentin around a foreign object due to the presence of a sharp cutting edge along its beveled tip. It can also serve as a microtube because of the presence of a lumen and a scope for modification of the tip to retrieve foreign objects from the root canal.[4]

The use of a syringe needle to dislodge or remove an obstruction from the root canal has many advantages. A syringe needle removes less dentin due to only end cutting, and unlike a rotary trephan, it does not have any potential to shave off the objects. It is available in various gauges to use according to the root canal dimensions and size of the obstructions. It effectively removes dentin when turned in both clockwise and counterclockwise directions.[4] A syringe needle provides tactile sense and scope for attaching a syringe to exert more pressure and lessen finger fatigue. It can also be used with a microscope or other magnification aids for better visualization. It is very economical for replacements.[4] Nevertheless, a syringe needle has certain drawbacks. Since it is selected on a trial and error basis, its effectiveness may not be predictable. It can cause ledging due to its sharp edge. It cannot be used beyond canal curvature due to the lack of flexibility and risks associated with its sharp edge. Its tip gets easily bent or dull and lumen gets easily clogged leading to ineffective application.[4]

In the present case, apart from the sharp beveled tip and the size of the syringe needle, its manual use in an arcing motion with good tactile sense aided in the removal of dentin in a conservative manner around the obstruction. The use of the syringe needle in a rocking motion helped to dislodge the obstruction.

CONCLUSION

In the absence of other means, the use of a disposable syringe needle is a simple, economical, and yet an effective technique to remove dentin in a conservative manner and to loosen or dislodge and remove a metallic obstruction from the root canal. However, its application and effectiveness depends on proper case selection and straight-line accessibility to the obstruction.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.