Influence of the Canal Contents on the Electrical Assisted Determination of the Length of Root Canals

Abstract

The purpose of this study was to compare the influence of the root canal status on the determination of the root canal length by an electronic apex locator in vital and necrotic canals and canals with root canal filling retrieval. One hundred seven teeth with a total of 171 canals with various contents (105 vital pulp, 47 necrotic pulp, and 19 retrieval of root canal filling materials) were measured for root canal length in vivo with the AFA Apex Finder. The distance between the file tip and the radiographic apex was also determined on radiographs. In 86% of the evaluated roots, the file tip position as indicated by the Apex Finder was located within 0.5 mm of a point 1.0-mm short of the radiographic apex. The Apex Finder showed higher accuracy for determining the apical constriction in vital canals (93.9%) than in necrotic canals (76.6%), and this difference was statistically significant (p < or = 0.05). The Apex Finder indicated the point -1 mm +/- 0.5 mm in canals with retrieval of root canal filling materials in 68.4% of these cases, but because of the small number of retrieval cases, this is not comparable statistically with vital and necrotic cases. The authors concluded that the AFA Apex Finder is highly accurate in vital canals.

Influence of pulp condition on the accuracy of an electronic foramen locator in posterior teeth: an in vivo study

“…Although some authors 8,24 have demonstrated a higher accuracy of EFLs in determining WL in vital canals, when compared with necrotic canals, the identical accuracy found in our sample regardless of pulp condition is in agreement with other studies. [5][6][7]9,10 The rate of acceptable measurements (73.61%), considering both vital and necrotic pulps, indicates that the NovApex  EFL is accurate and useful to determine WL under clinical circumstances.…”

“…endodontics, [4][5][6][7][8][9][10][11][12][13] has some advantages, e.g. the possibility to study root canal anatomy and to identify periapical lesions, as reported by ElAyouti et al 14 Conversely, one disadvantage of this method is related to the difficulties involved in locating the apical foramen and the apical constriction.…”

“…Early resistancebased EFLs proved inaccurate in the presence of conducting fluids. 8,15 Other types of EFLs work with alternating currents and are therefore compatible with different fluids present inside the root canal. 16 Recently, many authors, using different research designs, have attested to the accuracy of several EFL models.…”

An overview of electronic apex locators: part 2

“…Their statistical analyses suggested that these two values were significantly different from one another. Unlike Dunlap et al's study, 34 the findings of Pommer et al 37 suggest that third generation EAL work better in vital canals than necrotic canals. This makes sense from an impedance change (at the AC) point of view.…”

“…Pommer at al. 37 reported that it correctly identified the position of the AC in 94% of vital canals, but only 77% of the time in necrotic canals. Their statistical analyses suggested that these two values were significantly different from one another.…”