Clinical reproducibility of three electronic apex locators

The influence of periapical lesions on the repeatability of two electronic apex locators in vivo

OBJECTIVES

To determine the influence of periapical lesions on the repeatability of two electronic apex locators (EALs), Root ZX II, and RomiApex A-15, in maxillary anterior teeth, in vivo.

MATERIALS AND METHODS

After approval by the local ethics committee, 43 maxillary anterior teeth scheduled for root canal therapy were assigned to two groups. The periapical lesion (PAL) group included 21 teeth with necrotic pulps and radiographically visible periapical lesion, and the normal periapex (NPA) group consisted of 22 teeth with vital pulps and no periapical lesion. In each canal, Root ZX II and RomiApex A-15 were used to determine working length defined as the "zero" reading on the display. Two consecutive measurements were performed with each EAL on each tooth and a second operator measured the endodontic file with a digital caliper without knowledge of the EAL being used or the tooth diagnosis. The absolute value of the difference between the first and second measurement (measurement pairs) was calculated. Repeatability was evaluated by the Bland-Altman method, and an aligned ranks transformation ANOVA was conducted to compare the EALs.

RESULTS

The median absolute difference between measurement pairs was significantly lower (p < 0.001) and the limits of agreement were narrower in the NPA group. Among the EALs, median absolute differences were significantly smaller for Root ZX (p < 0.001).

CONCLUSIONS

Measurements were more repeatable when no periapical lesion was present. Root ZX showed better repeatability than RomiApex.

CLINICAL RELEVANCE

Periapical lesions seem to influence successive in vivo measurements with EALs.

Accuracy of Software-Based Three-Dimensional Root Canal Length Measurements Using Cone-Beam Computed Tomography

Objective

This study aims to evaluate the accuracy of three-dimensional root canal length measurements performed by dentists with different experience levels using a special software based on cone beam com-puted tomography (CBCT).

Methods

A CBCT scan of an artificial resin maxillary molar was used to train dentists (n=65) in using the software (3D Endo, DentsplySirona, Ballaigues, Switzerland) as part of a continuing education course. At the beginning, each participant completed a questionnaire on endodontic and CBCT experiences. After com-prehensive instructions, each participant performed an entire three-dimensional treatment plan by tracing the root canal anatomy between the apical foramen and the center of the canal orifice and simulating a straight-line access. The final root canal length was indicated after the virtual rubber stop of a simulated instrument was adapted to the adjoining cusp. To evaluate the individual accuracy in terms of trueness and precision, differences between the three-dimensional planning and the actual root canal length (ARCL) were calculated, and statistically analyzed.

Results

Mean absolute differences between the measurements with the 3D Endo™ software (n=260) and the ARCL were 0.30±0.22 mm. All measurements were within a limit of ±1 mm. The accuracy of root canal length measurements was significantly influenced by the type of root canal (p<0.0001). The smallest devia-tions were observed for the palatal root canal (0.18±0.13 mm), followed by the mesiobuccal (0.26±0.22 mm), the distobuccal (0.32±0.17 mm), and the second mesiobuccal root canal (0.46±0.24 mm).

Conclusion

Within the limitations of this study, the 3D Endo software enables reproducible and accurate root canal length measurements as part of a three-dimensional endodontic treatment plan. However, mea-surements should always be clinically verified, as root canal morphology has a statistically significant influence.

Evaluation of Correlation Between apical Diameter and File Size Using Propex Pixi Apex Locator

AIM

AIM of this study is to evaluate the influence of critical diameter of apical foramen and file size using propex pixi apex locator in working length determination.

MATERIALS AND METHODS

In this study, ten single rooted teeth were selected. They were decoronated at cemento enamel junction. After determining the actual working length, they were embedded in alginate mold. Foramina were widened from 0.6mm to 0.8mm. The measurements were taken with electronic apex locator propex pixi with files from sizes 10 K to respective sizes. Statistical accuracy of propex pixi was calculated by using Anova test for different diameters and for the influence of file size.

RESULTS

RESULTS showed that propex pixi apex locator was accurate when foramen diameter is 0.6 (60k file size), its accuracy diminished with increased foramen diameter

CONCLUSION

Propex pixi is accurate for foramen diameter of 0.6mm, independent of file size. Its accuracy decreases as apical foramen widens, so care should be taken when using clinically.

Accuracy of three electronic apex locators in determining the apical foramen in multi-rooted teeth: Randomised clinical and laboratory study

This study aimed to compare the accuracy of three electronic apex locators (EALs), Raypex 5, Apex NRG and ProPex II, in locating the apical foramen (AF) in vivo. Thirty multi-rooted teeth were included in the study. Distances from the file tip to the radiographic apex from the buccal (R1) and mesial (R2) aspect were measured after extraction. The distance from the file tip to the AF (L) was measured microscopically. Raypex 5, Apex NRG and ProPex II were accurate to within ± 0.5 mm in 84.6%, 78.6% and 66.7% of cases, respectively. R1, R2 and L measurements between the EALs were not statistically different (P > 0.05). R1 and L correlated positively (r(2) = 0.817; P < 0.001). There were no significant differences in all measurements between vital and non-vital root canals (P > 0.05). There was no statistically significant difference between the EALs. There was a positive correlation between electronic and radiographic measurements when locating the AF.

Accuracy of five electronic foramen locators with different operating systems: an ex vivo study

OBJECTIVE

The aim of this study was to evaluate, ex vivo, the precision of five electronic root canal length measurement devices (ERCLMDs) with different operating systems: the Root ZX, Mini Apex Locator, Propex II, iPex, and RomiApex A-15, and the possible influence of the positioning of the instrument tips short of the apical foramen.

MATERIAL AND METHODS

Forty-two mandibular bicuspids had their real canal lengths (RL) previously determined. Electronic measurements were performed 1.0 mm short of the apical foramen (-1.0), followed by measurements at the apical foramen (0.0). The data resulting from the comparison of the ERCLMD measurements and the RL were evaluated by the Wilcoxon and Friedman tests at a significance level of 5%.

RESULTS

Considering the measurements performed at 0.0 and -1.0, the precision rates for the ERCLMDs were: 73.5% and 47.1% (Root ZX), 73.5% and 55.9% (Mini Apex Locator), 67.6% and 41.1% (Propex II), 61.7% and 44.1% (iPex), and 79.4% and 44.1% (RomiApex A-15), respectively, considering ±0.5 mm of tolerance. Regarding the mean discrepancies, no differences were observed at 0.0; however, in the measurements at -1.0, the iPex, a multi-frequency ERCLMD, had significantly more discrepant readings short of the apical foramen than the other devices, except for the Propex II, which had intermediate results. When the ERCLMDs measurements at -1.0 were compared with those at 0.0, the Propex II, iPex and RomiApex A-15 presented significantly higher discrepancies in their readings.

CONCLUSIONS

Under the conditions of the present study, all the ERCLMDs provided acceptable measurements at the 0.0 position. However, at the -1.0 position, the ERCLMDs had a lower precision, with statistically significant differences for the Propex II, iPex, and RomiApex A-15.