Electronic length measurement using small and large files in enlarged canals

Abstract

Electronic apex locators are frequently used attached to a small size endodontic file; however, the effect on the measurement of the relative diameters of the file and the root canal has not been clarified. In this study, the length of enlarged canals was measured using small size files and files matching the canal diameter to observe a possible discrepancy. The accuracy of electronic length control during canal preparation with rotary files was also assessed. The root canals in 21 extracted, single rooted teeth were accessed, and their actual length (AL) established by passing a size 10 file just through the minor apical foramen. The teeth were then embedded in an alginate mold. The initial canal length (IL) was measured with the Root ZX apex locator by negotiating a size 10 file to the apical constriction. The canal was enlarged to size 60 with rotary files while the length was continuously controlled with the apex locator. Then, the final length measurements were obtained with a size 10 file and a size 60 file (FL-10 and FL-60, respectively). The average values of IL, FL-10 and FL-60 were calculated and compared using Repeated Measures Analysis of Variance followed by Tukey's Studentized Range test (P < 0.05). Using composite resin, the size 60 files were secured at the FL-60 length, the teeth were removed from the alginate mold, stained with Picroformal DI Buoin stain and the position of the file tip was observed histomorphometrically after the apical 4 mm of the canal was exposed by grinding the buccal aspect of the root. The IL was 0.45 mm shorter than AL (P < 0.05). The differences between FL-10, FL-60 and IL were not statistically significant. Histomorphometrically, the apical constriction was absent in all the teeth, but the file tips were confined within the root. This study concluded that the Root ZX indicated the location of an apical constriction even when the anatomic constriction was eliminated. In the enlarged canals, length measurements obtained with small and large size files were comparable.

In vitrocomparison of measurement accuracy in pre-enlarged and enlarged canals with four apex locators

“…Nguyen et al 19) reported the length measurement obtained with small and large size files were comparable in the enlarged canals. Similarly, all devices had not statistically significant differences between L10 and L40.…”

“…An in vivo study carried out by Shabahang et al 20) produced values to a precision of 96.2%. Also, Nguyen et al 19) showed that the accuracy of Root ZX was not affected by a wide apical foramen. An in vitro study of the Bingo 1020 found it to be as reliable as the Root ZX 17) .…”

“…Each tooth was mounted in alginate model embedded up to the cervical level so that an electronic apex locator could be used to measure canal length [16][17][18][19] . Then the canal length was measured using four devices of Table 1, with the lip-clip electrode embedded in the mold.…”

Risk analysis of failure of root canal treatment for teeth with inaccessible apical constriction

“…These devices enable clinicians to determine whether root canal instruments can reach the apex with ease and precision. [19][20][21][22] There are many reasons why apical constriction may not be accessible. 17 Severe curvatures, broken instruments, miscalculation of canal length, development of ledges, inadequate instrumentation 17 and obliteration of root canal 18 are among the most common reasons.…”

Working length determination methods in endodontics

“…Root ZX'in çalışma boyu tespitinde gösterdiği yüksek doğruluk oranı pek çok çalışmayla onaylanmıştır. [45][46][47][48][49][50][51][52][53] Dördüncü Nesil Apeks Bulucular Empedans ölçümünü, iki veya daha çok frekansı farklı zamanlarda kullanarak yaparlar (Tablo 1). 54 Kuru veya kuruya yakın kanallarda güvenilir ölçümler yapmalarına 55 rağmen nem, kan, eksuda, elektrolitlerin varlığında yanlış sonuçlar verebilirler.…”