Evaluation of alginate as a substitute for root‐surrounding tissues in electronic root canal measurements

Abstract

Alginate as a substitute for root-surrounding tissue was investigated. The electronic working lengths of root canals under clinical conditions were compared with an in vitro simulation of the same teeth extracted and embedded in alginate. The working lengths in 26 teeth were determined on two occasions using an electronic apex locator, before extraction and after extraction with the same teeth embedded in an alginate mass. The apical 4 mm of the root canals were exposed following the measurements, and the distances between the apical constrictions and the tips of files repositioned in the canals were measured and recorded. The mean distance between the file tip and the constriction was +0.33 mm (±0.38) in vivo and +0.32 mm (±0.30) in vitro. The Wilcoxon signed-rank test indicated that these means were not significantly different. The apical constriction was assessed to be within the limits of 0.5 mm in 80.7% of in vivo cases and in 76.9% of extracted teeth. Statistical analysis demonstrated that there was no significant difference between the results recorded in vivo and in vitro regarding apical constriction localisation. Based on the results of this study, the alginate mass is a useful tool in evaluating the performance of electronic apex locators.

Influence of the instrument used for cervical preflaring on the precision of 2 Eletronic Apex Locators

“…This increase is similar to those found in previous studies that used other EALs 15,[20][21] . This result can be due to a better adjustment of the file to the apical third 26 , promoting less exposure of metallic surface to the surrounding electrolyte and allowing the impedance reading in that region to be more effective 10 .…”

“…For this reason, the material that is commonly used is 1% agar, saline solution, alginate, gelatin or sponge soaked in saline solution 10,24 . In this study, the teeth were embedded in alginate to perform the measurements, as this Protocol facilitates samples preparation, provides high degree of stability, and leads to accurate measurements 20,22 . Furthermore, it is reported to be the most reliable and reproducible method 24 .…”

“…Studies have shown that when the determination of WL was performed without prior cervical enlargement, there was a higher incidence of cases where the file stopped short of or beyond the apical limit of the root canal 14,16 . To date, few studies that evaluated the influence of cervical preparation on measurements by EALs suggest that the accuracy of some devices was increased after cervical preparation 15,[20][21] .…”

N Vitrocomparison of the Accuracy of Two Apex Locators of Different Generations

“…In the research of Lipski et al alginate has proven to be a reliable medium for replacement of in vivo conditions during the electronic working length measurement. There was no statistically significant difference between the in vitro and in vivo measurements (21).…”

“…The other good properties of alginate are that is inexpensive, easy to prepare, stable for hours and relative stiffness of alginate model that prevents fluid movement within the canal and premature readings (19,20). It has been applied in a number of in vitro studies (6,10,17,21). In the research of Lipski et al alginate has proven to be a reliable medium for replacement of in vivo conditions during the electronic working length measurement.…”