JICDRO is a UGC approved journal (Journal no. 63927)

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Year : 2009  |  Volume : 1  |  Issue : 3  |  Page : 49-54

The evaluation of three electronic apex locators in teeth with simulated incomplete oblique root fractures

Department of Conservative, Endodontics & Esthetic Dentistry, Dr D. Y. Patil Dental College & Hospital, Pimpri, Pune, India

Date of Web Publication23-Feb-2011

Correspondence Address:
Lotika Beri
Department of Conservative, Endodontics & Esthetic Dentistry, Dr D. Y. Patil Dental College & Hospital, Pimpri, Pune
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Source of Support: None, Conflict of Interest: None

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Traumatic injuries to the tooth may lead to a dilemma in the treatment plan specially in teeth with fractured roots with displacement. The treatment plan for teeth with root fractured with displaced apical segment is to implement root canal therapy up to the fractured line leaving the apical segment untreated. Determining the working length of the coronal segment may be difficult by radiograph, so we tested the accuracy of three electronic apex locators (EALs) to locate the apical limit in teeth with simulated oblique root fractures. An oblique incomplete root fracture was simulated on 15 freshly extracted maxillary anterior teeth by means of a notch made on the vestibular root plane 8 mm from the anatomic apex. The EALs investigated were the ProPex (Dentsply Maillefer, Ballaigues, Switzerland), Root ZX (J.Morita Co, Kyoto, Japan). Dentaport ZX ( J. Morita Co., Kyoto, Japan). The electronic measurements were compared with the real "working length." The accuracy obtained was of 86.6% (n _ 13) with Root ZX , 66.6% (n _ 10) with the ProPex, and 60% (n _ 09) with Dentaport ZX. When tolerances of 0.5-mm and 1.0-mm tolerance were, respectively, allowed. The analysis of variance (p _ 0.05) and chi-square test (0.5 mm/p _ 0.47 and 1.0 mm/p _ 0.63 tolerances) showed no statistical significant differences between the EALs at either tolerance level.

How to cite this article:
Beri L, Matariya G. The evaluation of three electronic apex locators in teeth with simulated incomplete oblique root fractures. J Int Clin Dent Res Organ 2009;1:49-54

How to cite this URL:
Beri L, Matariya G. The evaluation of three electronic apex locators in teeth with simulated incomplete oblique root fractures. J Int Clin Dent Res Organ [serial online] 2009 [cited 2022 Jan 28];1:49-54. Available from: https://www.jicdro.org/text.asp?2009/1/3/49/77028

   Introduction Top

Andreason [3] found out that in the teeth with root fractures with displaced apical segment, the coronal segment becomes nonvital leaving apical segment with healthy vital pulp, hence the recommended treatment plan for these teeth is to implement root canal therapy upto the fracture line leaving the apical segment untreated. Adequate root canal system cleaning, shaping, and filling procedures are essential for a successful outcome of an endodontic treatment, so it is necessary to determine the apical limit, which is usually located approximately between 0.5 and 1.0 mm from the anatomic apex, but in teeth with fractured roots , the determination of the working length is more difficult with a radiograph because of the angulation of the fracture plane with respect to the root axis. The fracture plane is usually beveled buccopalatally, making its interpretation on radiographs difficult. Also the radiographs are influenced by factors such as tooth inclination, position of the x-ray media, angulations of the x-ray tube, and superimposition of anatomical structures among others. Hence the apex locators play an important role in determining the working length in such cases.

The aim of this investigation was to evaluate the ability of three frequency-based electronic apex locators to determine, in vitro, the coronal location of a 65° simulated horizontal root fracture.

   Materials and Methods Top

Fifteen freshly extracted human maxillary anterior teeth were selected for this study. After extraction, teeth were cleaned with 5.25% NaOCl for 15 minutes, and rinsed in a continuous water bath for 15 minutes. This was repeated twice to completely eliminate any root surface impurities. The root canal morphology was ascertained by means of radiographs made in a buccolingual and mesiodistal plane. The teeth were consecutively numbered for identification purposes during all procedures. The access cavities were prepared with a round diamond bur 012 (Mani), and the access cavity walls were finished with non-end cutting diamond bur under constant water cooling. The patency of the root canals was verified by means of a K-type file #15 (Dentsply Maillefer) before the root canal access enlargement, which was made with a tapered bur and irrigated with a 2.5% NaOCl (Farmadental) solution.

An oblique notch on the buccal root surface with an approximately 65° (±5°) angulation with respect to the tooth axis by means of a 0.4-mm diamond disk (Horico, Berlin, Germany) at low speed and under constant water coolant was made to simulate oblique incomplete root fracture.. The notch was made 8 mm from the anatomic apex of the root completely exposing the root canal. A remnant of hard tissue was left on the palatal side of the root, thus avoiding complete separation of the apical root segment [Figure 1]. The real "working length" (RWL) was determined by placing a thin spatula into the root fracture plane towards the coronal root segment, and a #25 K-type file (Dentsply Maillefer) was introduced until a firm contact with the spatula was made. The RWLs to the fracture plane or new apex were then recorded.
Figure 1:

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The roots of the teeth were placed up to the cementoenamel limit in a recipient containing alginate impression material. The roots of the teeth and labial clip of the EALs were introduced through perforation made in the model. The root canals were irrigated with a saline solution, and the pulp chambers were dried with a cotton pellet. The "working length" determination by electronic measurement of the roots was done from an incisal reference point to the root fracture plane with three different EALs: the ProPex (Dentsply Maillefer, Ballaigues, Switzerland), Root ZX( J.Morita Co, Kyoto, Japan), and Dentaport ZX ( J. Morita Co., Kyoto, Japan).

The employment of the EALs was made according to the manufacturer's recommendation, and the electronic working length was determined when 0.5 could be read in the light-emitting diode displays of the EALs.

Each root canal was measured with a K-type file (Dentsply Maillefer, Ballaigues, Switzerland) that could be fitted at the fracture plane of the coronal root segment. The same instrument was used for each root canal for all EALs. The same operator made all measurements.

The resulting data were recorded, and the results obtained were compared with the real length, allowing a tolerance of 0.5 and 1.0 mm. Measurements were obtained and those not within these limits were considered as unacceptable.

The differences between the EALs were analyzed with an analysis of variance. The measurements recorded with each EAL at the 0.5- and 1.0-mm tolerance levels were analyzed with the chi-square test (p _ 0.05).

   Results Top

A total of 45 "working length" electronic measurements were made, 15 with each EAL. The results obtained are summarized in [Table 1] (0.5-mm tolerance). Acceptable results at a 0.5-mm tolerance [Table 1] were obtained with the Root ZX in 86.6% (n _ 13), the Propex in 66.6% (n _ 10), and the Dentaport ZX in 60% (n_ 09). At this tolerance level, the Root ZX showed two measurements longer than the RWL; with the Propex , five measurements were longer than the RWL, and the Dentaport ZX showed, four shorter and two longer with respect to the RWL.

Table 1:

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   Discussion Top

The presence of root fractures as a consequence of dental trauma in permanent teeth has been observed with an almost 7% frequency [3] . Such fractures cannot always be diagnosed by means of a radiograph within the first hours after the dental trauma incident; thus, the necessity of periodical clinical and radiographic controls becomes necessary. Furthermore, the location of the fracture plane with respect to the root axis is also radiologically difficult. Andreasen and Andreasen and Lindhal [4] recommend the use of three different radiographs with different angulations to facilitate the diagnosis of a horizontal root fracture.

It is possible that the coronal root segment can loose vitality while the apical segment remains vital. Under such circumstances, different authors have suggested performing an endodontic treatment only on the coronal root canal segment and considering the fracture plane as the limit of the working length. Yet, an accurate localization of the cleaning, shaping, and filling limit in such cases is often a difficult procedure for the operator because of the ambiguous radiologic interpretation of the fracture plane angulation.

Several investigators [5],[8],[9] have shown that EALs are reliable to determine the working length. Thus, it was our aim to confirm the reliability of three different EALs in simulated clinical conditions in which an oblique root fracture is present.

Azabal et al. [10] conducted a similar study in which only one device (Justy II) was investigated. These authors reported a 93.5% and 100% of accurate measurements when allowing a_0.5- and_1.0-mm tolerance, respectively. These results are not in agreement with the ones obtained in this investigation in which the results with the different EALs were between 60% and 86.6% for tolerances of 0.5 mm. 10 In this investigation, contrary to the report of Azabal et al. the crowns of the teeth were not separated, thus keeping the research variables closer to an in vivo situation. Furthermore, the determination of the real working length was made when the measuring instrument reached a firm contact with the spatula at the fracture plane, instead of a 2.5 X visual magnification, which may have allowed no margin of error. In the present study, results at a 0.5 mm tolerance were obtained with the Root ZX in 86.6% (n _ 13), the Propex in 66.6% (n _ 10), and the Dentaport ZX in 60% (n_ 09). No statistical significant differences were observed between the different EALs.[11]

   Conclusion Top

Under the experimental conditions of this investigation, it can be concluded that the investigated EALs are capable of determining the working length of the coronal root canal segment in teeth with oblique root fractures, hence making electronic apex locator an invaluable tool while treating teeth with fracture root.

   References Top

1.Ponce EH, Vilar Fernández JA. The cemento-dentino-canal junction, the apical foramen, and the apical constriction: evaluation by optical microscopy. J Endod 2003;29:214 9.  Back to cited text no. 1
2.Palmer MJ, Weine FS, Healey HJ. Position of the apical foramen in relation to endodontic therapy. J Can Dent Assoc (Tor) 1971;37:305 8.  Back to cited text no. 2
3.Andreasen J, Andreasen F. Textbook and color atlas of traumatic injuries to the teeth. Ed 3. Copenhagen: Munksgaard; 1994.  Back to cited text no. 3
4.Cvek M, Mejare I, Andreasen JO. Conservative endodontic treatment of teeth fractured in the middle or apical part of the root. Dent Traumatol 2004;20:2619.  Back to cited text no. 4
5.Lucena-Martin C, Robles-Gijon V, Ferrer-Luque CM, de Mondelo JM. In vitro evaluation of the accuracy of three electronic apex locators. J Endod 2004;30:2313.  Back to cited text no. 5
6.Pratten DH, McDonald NJ. Comparison of radiographic and electronic working lengths. J Endod 1996;22:173 6.  Back to cited text no. 6
7.Shabahang S, Goon WW, Gluskin AH. An in vivo evaluation of Root ZX electronic apex locator. J Endod 1996;22:6168.  Back to cited text no. 7
8.Briseño-Marroquin B, Frajlich S, Goldberg F, Willershausen B. Influence of instrument size on the accuracy of different apex locators: an in vitro study. J Endod 2008;34:698 702.  Back to cited text no. 8
9.Herrera M, Abalos C, Planas AJ, Llamas R. Influence of apical constriction diameter on Root ZX apex locator precision. J Endod 2007;33:9958.  Back to cited text no. 9
10.Azabal M, Garcia-Otero D, de la Macorra JC. Accuracy of the Justy II Apex locator in determining working length in simulated horizontal and vertical fractures. Int Endod J 2004;37:174 7.  Back to cited text no. 10
11.Ebrahim AK, Wadachi R, Suda H. Accuracy of three different electronic apex locators in detecting simulated horizontal and vertical root fractures. Aust Endod J 2006;32:64 9.  Back to cited text no. 11


  [Figure 1]

  [Table 1]


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