Journal of Dental Medicine

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Statement of Problem: Radiography is the most common technique in working length determination, however, because of its limitations is not considered as an ideal technique. Its application, particularly for children due to radiation hazards, technical problems in young and unco-operative children and the superimposition of permanent teeth bud on primary teeth root, lead to numerous problems.
Purpose: The goal of this study was to evaluate the accuracy of an electronic apex locator (EAL) in working length determination of primary teeth.
Materials and Methods: In this in-vitro study 96 canals of the extracted primary teeth, with at least 2/3 of the root length remained, were investigated. There were no obstructed canal, previous root canal therapy and perforation of pulp chamber floor. All working lengths were also measured by radiography. The results of Raypex 4 and radiography were compared with actual root canal lengths determined by direct observation. The applied EAL, in this study was called Raypex 4, a new device belonged to the fourth generation (Ratio Type). The results were analyzed by Chi-Square and Pearson correlation statistical tests.
Results: The accuracy of Raypex and radiography were 61.5% and 63.5%, respectively. The differences between Reypex 4 root canal length measurements and those of direct observation were not significant (P=0.08), but such difference between radiography and direct observation was statistically significant (P=0.01). The diameter of the apical foramen (the site of canal opening) did not affect on Raypex 4 accuray (P>0.05).
Conclusion: Considering the acceptable safetyness, Painlessness, simple and rapid application and an accuracy comparable to that of radiography, the use of Raypex4 EAL for the measurement of primary teeth length is suggested.

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Background and Aim: Determining correct working length in root canal therapy is of great importance in successful treatment. The purpose of this study was to compare the accuracy of two electronic apex locators of fourth generation, Raypex4 and Apit7, in determining working length in vivo.

Materials and Methods: In this test evaluation study performed at Dental School of Tehran University, a total of 32 single canal vital teeth planned for extraction because of orthodontic and prosthetic reasons were selected. Working length determination by each of the two electronic apex locators was performed by two different dentists. These measurements were compared with direct visual measurement after tooth extraction. The dentists working with devices and the endodontist who determined the working length of the extracted teeth as well as the statistician, all were blind regarding the results. The data were compared using binominal distribution test with P<0.05 as the limit of significance.

Results: The accuracy of actual length determination of Raypex4 was 68.8% in the limit of ± 0.5 and 83.3% in the limit of ±1. From the actual length measurements, 75.1% were within the tolerance of +0.5 to-1. The accuracy of the working length determination by Raypex4 was 68.8% within the tolerance of ± 0.5 and 84.3% within the tolerance of ± 1. Taking the tolerance of + 0.5 to -1 mm into account, the accuracy of the instrument was about 78.8%. The accuracy of actual length determination of Apit7 was 65.7% in the limit of ±0.5 and 78.3% in the limit of ±1. Compared to the visual length determination, 78.8% of the actual length measurements were within the tolerance of +0.5 to-1. The accuracy of the working length determination was 62.6% within the tolerance of ±0.5 and 81.3% within the tolerance of ±1. Taking the tolerance of + 0.5 to -1 mm into account, the accuracy of the instrument was about 75.1%.

Conclusion: Raypex4 and Apit7 had similar accuracy in determining the actual length. However, they still can not replace the routine methods of actual length determination.

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Background and Aim: Radiography is the most commonly used technique in root canal length determination, but its application in pedodontics is difficult due to many problems such as radiation hazards, superimposition of permanent teeth buds and uncooperative children. The aim of this study was to investigate the accuracy of an electronic apex locator (Dentaport ZX) in measuring the root canal length of primary teeth in vivo.

Materials and Methods: In this test evaluation study, pulp tissues of 52 primary teeth planned to extraction were removed and the canal length were measured by Dentaport ZX. After extraction, real lengths of canals were measured by using# 15 K-Type file with 0. 1 mm accuracy and both measurements were compared. Data were analyzed by Smirnov Kolmogorov, chi-square, ANOVA and intraclass correlation and p<0.05 was considered as the limit of significance.

Results: The difference between the canal lengths measured by eye and Dentaport ZX was–0.17±0.384 mm. Maximum deviation of the real length of canals was between-0.2 to+0.2 mm from apical foramen. Accuracy of Dentaport ZX in the range of-0.2 to+0.2 from apical foramen was 66.96% and in the range of-0.5 to+0.5 from apical foramen was 92.17%.

Conclusion: Based on the results of this study, the use of Dentaport ZX in endodontic treatment for primary teeth could be advisable.