Micro-CT study of the in vivo accuracy of a wireless electronic apex locator

Evaluation of heated sodium hypochlorite's effect on the accuracy of contemporary electronic apex locators: an in vitro study

BACKGROUND

Accurate determination of the working length (WL) is essential for successful root canal therapy. Although electronic apex locators (EALs) are widely used for this purpose, the impact of irrigant temperature on their precision remains poorly understood. Therefore, in this study, we investigated the effect of variations in sodium hypochlorite (NaOCl) temperature on the performance of modern EALs, with particular emphasis on the recently introduced EAL, Ai-Pex.

METHODS

Twenty extracted human teeth were embedded in alginate to simulate clinical conditions. WL was measured using four EALs (Root ZX Mini, Propex Pixi, Raypex 6, and Ai-Pex) under three NaOCl temperature conditions: 19.4 °C (± 1.5 °C), 36 °C, and 70 °C. A dental operating microscope was used to determine the actual working length (AWL). Deviations between electronic and AWLs were recorded, and statistical analyses were conducted using repeated-measures analysis of variance (ANOVA) and chi-square tests.

RESULTS

All EALs exhibited high accuracy, with deviations within ± 0.5 mm of AWL across all NaOCl temperature conditions (p > 0.05). Ai-Pex achieved 95% accuracy at room and body temperatures and 100% accuracy at 70 °C. Similarly, Root ZX Mini, Propex Pixi, and Raypex 6 demonstrated consistent performance, with no statistically significant differences in accuracy across temperature groups.

CONCLUSIONS

This study confirms that variations in NaOCl temperature do not significantly impact the accuracy of EALs in determining the WL for root canal therapy. These findings underscore the reliability of contemporary EALs under different clinical conditions, including the newly evaluated Ai-Pex. Further, in vivo studies are necessary to validate these results.

The evaluation of the accuracy of a wireless electronic apex locator in primary molar teeth

BACKGROUND

The working length determination is necessary before root canal shaping, chemical cleaning, disinfection, and obturation in pulpectomy of primary dentition. This study aimed to evaluate the accuracy of Wirele-X and compare it with DentaPort ZX and Woodpex III in primary molar teeth.

METHODS

The in vitro study was performed by using 30 extracted primary mandibular molar teeth. In distal roots, the actual working length was determined by taking forward a #10 K-type canal file under a dental operating microscope with 10x magnification. Each tooth and lip clip were embedded in alginate before determining the working lengths using electronic apex locators. The average of three electronic working lengths was calculated for each sample, and the actual working length was subtracted from the electronic working length.

RESULTS

There were no significant differences in the accuracy rate of DentaPort ZX, Wirele-X, and Woodpex III in the determination of the working length set at ± 0.5 mm and ± 1 mm, respectively (P > 0.05).

CONCLUSIONS

This study reported that DentaPort ZX, Wirele-X, and Woodpex III can be safely used in the pulpectomy of primary molars. Wirele-X can provide an advantage in working length determination in children because of its wireless feature.

Accuracy of Root ZX Electronic Apex Locator in Relation to Two Different Employment Protocols: An In Vitro Study

Objective The aim of this study is to determine the apical level of the root canal, whether it is the apical foramen or a level coronal to it, that Root ZX (J. Morita Co., Kyoto, Japan) targets and to identify its employment protocol that provides better accuracy. Methods Actual lengths (ALs) of 75 extracted single-rooted teeth were obtained by inserting a K-file size 8 until its tip was in level with the most coronal border of the apical foramen. Reference length (RL) was calculated by deducting 0.5 mm from AL. Roots were placed in porous sponge block soaked with Ringer's solution, and canals were irrigated with 2 mL of 5% sodium hypochlorite. The blinded operator used Root ZX to measure lengths with K-file size 8. In the first tested employment protocol, the file was advanced to the "APEX mark" of the digital display, and the length was obtained. The second employment protocol followed the manufacturer's recommendations by inserting the file until the "APEX mark" followed by its withdrawal to the "0.5 mark." Stability of the digital meter for 5 seconds was mandatory before recording the lengths. All measurements were repeated one week later and then both measurements were averaged to represent "APEX mark" and "0.5 mark," respectively. Data were analyzed using t-test, with significance set at 0.05. Results Regardless of the employment protocol, most registered lengths were longer than targeted. The mean "APEX mark" was significantly longer than the mean AL (P=0.000), and the mean "0.5 mark" was significantly longer than the mean RL (P=0.000). Although the mean "0.5 mark" was longer than the mean AL, the difference was not significant (P=0.07). Conclusion The apical level of the root canal targeted by the Root ZX was the apical foramen. The most accurate employment protocol to achieve that is to use the Root ZX according to the manufacturer's recommendations.

Clinical accuracy and precision of 3 multi-frequency electronic apex locators assessed through micro-CT imaging

INTRODUCTION

This study aimed to compare the in vivo accuracy and precision of 3 electronic apex locators (EALs) in determining the position of the major foramen using micro-computed tomographic (micro-CT) technology.

METHODS

After access preparation of 23 necrotic or vital teeth from 5 patients, canals were negotiated and hand files were used to determine the position of the foramen with 3 EALs: Propex Pixi, Woodpex III and Root ZX II. After fixing the silicon stop to the file, teeth were extracted and scanned in a micro-CT device with and without the instrument inserted into the canal. Datasets were co-registered, and the accuracy and precision of the EALs were determined at a tolerance level of ± 0.5 mm by measuring the distance from the tip of the instruments to a tangential line crossing the margins of the foramen. Statistical comparisons were performed using Friedman with post hoc Related Samples Sign and Spearman tests (α = 5%).

RESULTS

A significant difference was detected comparing the accuracy of Root ZX II (100%), Woodpex III (86.96%) and Propex Pixi (52.17%) (P < .05). There was a lack of significance in the relationship between the pulp status and the accuracy of tested EALs (P > .05). Propex Pixi was significantly less precise than Root ZX II (P < .05), while no difference was found between Woodpex III to either Root ZX II or Propex Pixi (P > .05).

CONCLUSIONS

EALs presented similar precision, but Woodpex III and Root ZX II showed better accuracy to determine the position of the apical foramen than Propex Pixi.