|Year : 2012 | Volume
| Issue : 1 | Page : 41-45
Retrieval of separated instruments using a combined method with a modified vista dental tip
Mohammad S Al-Zahrani1, Saad Al-Nazhan2
1 Al-Baha Dental Center, Al-Baha, Saudi Arabia
2 Department of Restorative Dental Sciences, Division of Endodontics, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
|Date of Web Publication||10-Dec-2012|
Mohammad S Al-Zahrani
Ministry of Health, Al-Baha Dental Center, Al-Baha
Source of Support: None, Conflict of Interest: None
Biomechanical preparation of the entire root canal system is one of the most important procedures in endodontic treatment. Separation of instruments while preparing root canals presents a compromised situation in which a biologically inert segment is left behind with potential contamination that has the ability to affect the healing process. Management of this procedural error is tedious and requires creativity as well as clinical knowledge and skills. In this report, we demonstrated two cases with separated instrument in which a combined technique of ultrasonic method with microtube tube method was used to retrieve the separated tips using a modified Vista dental tip.
Keywords: Modified vista tip, retrieval, separated instrument
|How to cite this article:|
Al-Zahrani MS, Al-Nazhan S. Retrieval of separated instruments using a combined method with a modified vista dental tip. Saudi Endod J 2012;2:41-5
|How to cite this URL:|
Al-Zahrani MS, Al-Nazhan S. Retrieval of separated instruments using a combined method with a modified vista dental tip. Saudi Endod J [serial online] 2012 [cited 2020 Jan 25];2:41-5. Available from: http://www.saudiendodj.com/text.asp?2012/2/1/41/104421
| Introduction|| |
In endodontic clinic, variety of procedural complexities could be encountered at any stage of the treatment. One of the most sophisticated obstacles is intraradicular instrument separation. The separated instrument could be endodontic files, Gates Glidden burs, and spreaders. Fracture often results from incorrect use or overuse of an endodontic instrument. 
Recently, the advent of rotary NiTi instruments has led to a perceived high risk of instrument separation.  Furthermore, the separation of rotary NiTi instruments may occur without warning;  the mean clinical separation frequency of rotary NiTi instruments is approximately 1.0% with a range of 0.4 to 3.7%. ,, The reasons for separation of rotary NiTi instruments are complex and multifactorial; ,, separated rotary NiTi instruments have been classified into those that fail as a result of cyclic flexural fatigue or torsional failure  or a combination of both.  There are factors predisposing to separation such as instrument design, manufacturing process, dynamics of instrument use, canal configuration, preparation technique, cleaning and sterilization process, and number of uses. 
Some studies report no effect on the healing of root-filled teeth with a retained instrument fragment, , while others reported a lower rate of healing when a separated instrument was present.  A retained fractured instrument per se generally did not adversely affect endodontic case prognosis.  The presence of a preoperative periapical radiolucency rather than the fractured instrument is clinically more significant and demonstrates the major negative influence of established and advanced root canal infections. ,, Additionally, two potentially important prognostic variables, inadequate size and apical extent of the fractured instrument, could have an impact on prognosis.
The retrieval of separated instruments is usually very difficult and often ineffective.  Different methods have been proposed for retrieving objects separated intraradicular. In the past, chemicals such as hydrochloric acid, sulfuric acid, and concentrated iodine-potassium iodide were used in an attempt to dissolve the metal obstruction,  which is now irrelevant because of the metals used today as well as the obvious safety issues. Recently, specialized devices and techniques have been introduced specifically to remove separated instruments such as ultrasonic devices, IRS, and Masserann kit. All these devices have shown limitations,  such as excessive removal of root canal dentin, ledging, perforation, limited application in narrow and curved roots, and extrusion of the separated portion through the apex. ,
This paper reports two cases with separated instrument in which a combined technique of an ultrasonic method and a microtube method was used to retrieve the broken tips using a modified Vista dental tips.
A 42-year-old female patient was referred for removal of a separated instrument (profile size 35 and 25) in the maxillary right lateral incisor. The medical history was noncontributory. On clinical examination, there was an access cavity filled with a temporary filling that was done through a porcelain crown. There was no evidence of either swelling or sinus tract in relation to it. No periodontal pockets were present. Radiographic evaluation of the involved tooth revealed two separated instruments that extend from the middle third to almost the radiographic apex and it revealed also a periapical radiolucency [Figure 1]a.
|Figure 1: Preoperative PA radiograph (a). PA radiograph after retrieval of the first file (b). The separated file connected to the tube and to K-file (c).|
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A straight line access to the coronal end of the separated file was first prepared by removal of the porcelain crown, then using a modified Gates Glidden burs (size 3 -Dentsply-Maillefer), a staging platform was created. A circular groove, 2 mm deep, was prepared around the coronal end of the file using ultrasonic tips (BUC-1A - Obtura Spartan Endodontics) and an operating microscope (Zeiss OPMI Pico operating microscopes). A Vista dental tip, 21 gauges, (Vista Dental Product, Racine, WI, USA) was customized by reducing the length of its plastic hub, then it was pushed over the exposed end of the separated instrument. A K file (size 40) was pushed using a clockwise rotation mode through the needle passing beyond the tip of the separated instrument, and alongside it until the K file cannot progress any further. At this point, a very tight connection was formed between the K file, needle, and separated instrument. By rotating in a counter clockwise direction and pulling on the hub of the needle, the three connected objects were readily withdrawn from the root canal [Figure 1]b and c. The instrument was removed at the first attempt. The floating second separated file was then removed using ultrasonic methods in which a fine ultrasonic tip (CPR-6 - Obtura Spartan Endodontics) was activated with low power beside the separated instrument tip while touching it. By doing so, the separated instrument successfully jumped out of the canal. The nonsurgical root canal treatment was then completed using profile (Dentsply, Maillefer) and sodium hypochlorite 5% for biomechanical preparation and obturated using the lateral compaction technique with gutta percha and AH-26 sealer (Dentsply, Detrey Gmbh, Germany) [Figure 2]a, b, c. One-year follow-up radiograph shows healing of the periapical lesion [Figure 2]d.
|Figure 2: PA radiograph after retrieval of the second file (a). Working length radiograph (b). Postoperative (obturation) radiograph (c). Recall radiograph after one year (d).|
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A 16-year-old female patient was referred for the removal of a separated instrument (Gates Glidden size 2) in the maxillary right lateral incisor. The medical history was noncontributory. On clinical examination, there was an access cavity filled with a temporary filling. There was no evidence of either swelling or sinus tract in relation to it. No periodontal pockets were present. Radiographic evaluation of the involved tooth revealed a separated Gates Glidden which was located in the apical third and it also revealed periapical radiolucency [Figure 3].
|Figure 3: Preoperative (diagnostic) PA radiograph showing the separated GG (a). After retrieval of the GG (b).|
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An access cavity was modified to gain straight line access to the separated Gates Glidden (GG) by removing the coronal obstructing restoration using a tapered diamond bur and removing the lingual shoulder using GG bur (size 3- Dentsply-Maillefer). A Vista dental tip gauge 21 (Vista Dental Product, Racine, WI, USA) was customized by reducing the length of its plastic hub, then it was pushed over the exposed end of the separated GG. A Hedström file (size 35) was pushed using a clockwise rotation mode through the needle passing beyond the tip of the separated instrument, and alongside it until the Hedström file cannot progress any further. At this point, a very tight connection was formed between the H file, needle, and separated GG. By pulling on the hub of the needle and rotating in a counter clockwise direction, the three connected objects were readily withdrawn from the root canal. The instrument was removed at the first attempt [Figure 4]. The nonsurgical root canal treatment was then completed using profile (Dentsply Maillefer) and sodium hypochlorite 5% for biomechanical preparation and obturated using the lateral compaction technique with gutta percha and AH-26 sealer (Dentsply, Detrey Gmbh, Germany) [Figure 5].
|Figure 5: Working length radiograph (a). postoperative (obturation) (b).|
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| Discussion|| |
Straight-line access is mandatory for successful removal of the separated instruments, ,, and it is also necessary for prevention of instrument separation. In both cases, the main cause of instrument separation is judged to be inappropriate access cavity that obstructs the straight line access. However, conservation of tooth structure is paramount to the tooth's resistance to fracture.
The technique presented in this report functions best with accurate gauges and lengths of the tube and with correctly sized files. Vista dental tips manufactured with different needle gauges. Determination of the accurate size of the needle is dependent on the size of the separated instrument and the canal diameter. Usually, the useful size is gauge 21 for most of the separated instrument sizes. Customizing the needle by cutting its plastic hub is aimed to reduce the length of the vista dental tip to allow a file with length 25 mm to pass beyond the needle tip. Matching the appropriate size of the file is done by trial and error. The engaging file should not be large, so it will not be able to pass the separated instrument inside the needle, and it should not be small, so it will not be able to engage the separated instrument inside the needle. This concept was initially recommended for retrieval of a separated silver point and instrument using stainless steel tube and H-file.  Difficulties may be encountered if the file is too large or the piece of needle is too long.
Successful removal of such obstructions relies on factors such as the position of the instrument in relation to the canal curvature, the depth within the canal, and the type of separated instrument. 
An attempt to bypass a separated instrument should always be initially considered because it can often be successful.  However, bypass of a separated long fragment carries a high chance of errors such as engagement of the bypassing file around the separated fragment, or perforation of the root; therefore, care should be taken if bypass is attempted in such cases. In the first case, the second separated file was separated while bypassing the first long separated file using rotary file; therefore, it is not advisable to use a rotary file to bypass a long separated instrument.
Retrieval of obstructions using Masserann instruments  requires a large access canal, with a diameter of at least 1.2 mm to be prepared. This procedure has a high risk of perforating the root. The Endo Extractor technique often contaminates the canal walls with adhesive and will be effective only if the separated instrument is loose.  On the other hand, the braiding technique  is less effective, because there is no constant tight bonding to the separated instrument. The ultrasonic  techniques are frequently effective in the retrieval of the separated instrument However, a large amount of time may be required to loosen tightly blocked instruments using ultrasonic tips. In contrast, the wire loop technique  requires that sufficient amount of the object be exposed so that it can be grasped by the wire loop.
In conclusion, this system renders a safe, inexpensive, and predictable method of retrieving separated tips from root canals. It is safe in regards to amount of removed dentin. The used tube to retrieve the separated instrument (i.e., vista dental tips) is inexpensive and could be available in all the dental clinics. It is predictable in the sense that it was successfully used. This system gives dentists another armamentarium for the retrieval of separated instrument.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]