An in vivo comparison of two frequency-based electronic apex locators

Comparative Accuracy and Reliability of Three Electronic Apex Locators in Determining the Apical Constriction of Molar Canals: A Micro-CT Evaluation

Background: Determining the correct apical limit for root canal treatment is essential for its success. This study evaluates the accuracy of three electronic apex locators (EALs) in locating the apical constriction (AC) in molar canals. Methods: Forty extracted human mandibular molars were scanned using micro-CT, and endodontic access cavities were created. Teeth were mounted in alginate, and three EALs-Root ZX-mini, Root ZX-II, and Sirona integrated apex locator-were used to measure the canal working length in dry canals and with EDTA gel. Micro-CT scans were performed with files in place, and the distance from the AC was calculated. Measurements within 0.1-0.5 mm were categorized as 'close'. Those extending beyond towards the major foramen were categorized as 'beyond', otherwise they were classified as 'far'. Data analysis was conducted with a level of significance set at 5%. Results: Most readings for all EALs were in the 'close' category, with significant differences between devices (p < 0.0001). Root ZX-mini and Root ZX-II had 74.4% and 72.5% 'close' readings, respectively, versus 51% for Sirona integrated. Accuracy did not differ significantly between dry and EDTA-treated canals (p = 0.306). All EALs demonstrated excellent operator reliability (ICC 0.996-1.00). Conclusions: All EALs accurately determined AC, unaffected by lubricants. However, Root ZX-mini and Root ZX-II outperformed Sirona integrated. All EALs showed consistent reliability.

Comparative evaluation of the accuracy of two electronic apex locators in detecting simulated incomplete vertical root fractures: An in vitro stereomicroscopic study

Aim

The aim of this study was to compare the accuracy of two different electronic apex locators (EALs) in detecting simulated incomplete vertical root fractures (VRFs).

Materials and Methods

Thirty freshly extracted single-rooted teeth were randomly divided into three groups of 10 teeth each labeled as Groups A, B, and C. Incomplete VRFs were simulated in the coronal, middle, and apical one-third of the roots for Groups A, B, and C, respectively. The teeth were embedded in alginate mold and fracture location was determined with Root ZX and Propex EALs for each sample and each group. To calculate the actual length (AL), each sample was sectioned at the upper level of the vertical fracture, and the length was measured by setting the stopper of the #10 K file under a stereomicroscope at ×30 magnification. The electronic lengths and ALs were compared using computer software, and the results were analyzed using SPSS 28.0 at a 95% confidence level.

Results

No significant differences were seen in the accuracy of the two EALs when compared with ALs. Root ZX showed significantly longer measurements than ALs in groups B and C.

Conclusion

The tested EALs showed low accuracy (20%) in detecting simulated incomplete VRFs with a tendency for longer measurements compared to ALs.

Accuracy of the electronic apex locator, tactile, and radiographic methods in working length determination

Background

Determination of working length (WL) is necessary for the successful outcome of root canal treatment (RCT). Common methods in WL determination include tactile, radiographic, and electronic apex locators (EAL).

Aim

The aim of this study was to compare three methods of WL determination to the actual visualization of the apical constriction (AC).

Materials and Methods

Consecutive patients with indications for extraction of single-rooted single canal teeth at the University of Ghana Dental School clinic were randomly assigned to three groups. In-vivo root canal WL was determined by tactile sensation, digital radiography, and a 5th generation EAL (Sendoline S5). Files were cemented in the canals after the in-vivo measurements. The apical 4-5 mm of the roots was trimmed to expose the inserted files and the AC. Actual WL, as determined by visualization of the AC, was done using a digital microscope. Different WLs were then compared for the various groups, and the mean actual canal lengths were reported.

Results

EAL accurately predicted the AC in 31 (96.9%) teeth, while the digital radiographic and tactile sensation methods accurately predicted the constriction in 19 (59.4%) and 8 (25%) teeth, respectively, in the study population. The mean working canal lengths for single-rooted teeth showed no observable difference among sexes, age categories, and side of the jaw.

Conclusion

The EAL provided more reliable and accurate WL measurements for single-rooted teeth among Ghanaians, compared to digital radiography and tactile methods.

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.

Influence of Open Apex on Working Length Determination Using Cone-Beam Computed Tomography and Apex Locators: A Comparative In Vitro Study

Objectives

The aim of this study is to assess the effect of open apex on working length (WL) determination with aid of cone-beam computed tomography (CBCT) and electronic apex locators (EALs).

Methods

Thirty-two extracted human mandibular premolars were selected, and apical 5 mm was removed. Root canals were prepared from the apical to the coronal direction of the canal using peeso reamers up to size 5 (retrograde) to simulate open apex. The samples were analyzed by CBCT, and WL was established (CWL) by a radiologist. An endodontist prepared the access cavities, and visual working length (VWL) was recorded. The samples were embedded in a freshly mixed alginate mould up to cementoenamel junction. Each root canal length was measured with two different EALs—Root ZX mini and i Root. The measurements were repeated 3 times by using a digital caliper, and the mean was recorded by the endodontist who was blinded to the results of the CWL. The recorded data was statistically analyzed using the SPSS software.

Results

The results of this study showed statistically significant difference between VWL and i Root, CWL and i Root, and Root ZX mini and i Root (p < 0.05). Amongst EALs, a superior accuracy was noted for Root ZX mini than as compared to i Root. However, no statistically significant difference was seen between Root ZX mini and CWL (p > 0.05).

Conclusion

The present study showed that CWL is as accurate and reliable as VWL which is the gold standard. Amongst EALs, Root ZX mini performed more accurately than i Root. Preexisting CBCT scans should be used as an advantage in determining WL.

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

INTRODUCTION

This study aimed to compare the in vivo accuracy of Wirele-X and RootZX II electronic apex locators (EALs) in determining the position of the major foramen using micro-CT as analytical tool.

METHODS

Eleven vital teeth from 5 patients planned for extraction were used. After conventional access cavity preparation, root canals were flared and negotiated up to the apical third with sizes 08 and 10 K-files followed by irrigation with 2.5% NaOCl. K-type files were used to determine the working length of the selected canals using Root ZX II and Wirele-X apex locators until their numeric displays read '0.0'. After fixing the silicon stop to the file, teeth were extracted and imaged in a micro-CT device using a double-scan protocol. Image stacks, with and without the file in the root canal, were then co-registered and the measurement error calculated as the absolute difference between the tip of the file and the major foramen. Positive and negative values were recorded when the file tip was detected beyond or short the major foramen, respectively. Accuracy was determined on stable measurements within ± 0.5 mm when the file tip did not extend beyond the major foramen. The Chi-square test was applied to compare the ability of the EALs to detect the position of the major foramen, while T test for dependent variables was used to verify differences in the two measurements obtained in each tooth. Significance level was set at 5%.

RESULTS

Within a tolerance level of ± 0.5 mm, no significant differences were observed between the tested EALs regarding the absolute distance values (p=0.82) or in their ability to detect the position of the major foramen (Χ²=0.2588; p=0.6109). The accuracy of the Root ZX II and the Wirele-X apex locators within ± 0.5 mm were 81.8% and 90.9%, respectively.

CONCLUSIONS

Root ZX II and Wirele-X performed similarly regarding the in vivo detection of the major foramen. Using strict criteria, the accuracy of the Root ZX II and the Wirele-X apex locators were 81.8% and 90.9%, respectively.

Comparison of Accuracy of Dentaport ZX, Rootor and E-Pex Pro Electronic Apex Locators in Two Simulated Clinical Conditions: An In Vitro Study

Background:

Materials and Methodology:

Results:

Conclusion:

Accuracy of working length measurement by Raypex 6: Electronic apex locator versus actual measurements under stereomicroscope

Background/Aim: This study aimed to evaluate the precision of the Raypex 6 apex locator in locating the apical constriction (AC) and major foramen (MF) during a root canal treatment compared with a microscopic evaluation. Another aim of the present study was to evaluate the accuracy of the Raypex 6 in the presence of different irrigating solutions (NaOCl, saline, EDTA, etidronic acid-HEBP). Material and Methods: One hundred and nine patients were included in this study and were randomly assigned into four groups according to the irrigation solution used; NaOCl, EDTA, HEBF and saline. Electronic MF (EMF) and AC (EAC) were measured by using Raypex 6. The teeth were extracted. The apical 3 mm of each canal was trimmed to expose the file tip. The samples were observed under a stereomicroscope, and the actual length of MF (ALMF) and AC (ALAC) were measured. The data were analyzed by using x2 test, and significance was set at P< 0.05. Results: The Raypex 6 was accurate 71.4% of the time to ±0.5mm and 93.3% of the time to ±1mm in determining the ALAC. While similar ALAC-EAC differences were observed in EDTA, NaOCl, and saline groups (p= 0.230), the highest differences were seen in the HEBP group (p= 1.000). The precision of Raypex 6 in determining the working length measurement depends on the type of irrigation. All solutions allowed reliable detection of AC. However, HEBF significantly increased the risk of overpreparation. Conclusions: Raypex 6 can be recommended for clinical use and its accuracy is not affected by the type of irrigant when locating MF.

Multifrequency Impedance Method Based on Neural Network for Root Canal Length Measurement

Root canal therapy is the most fundamental and effective approach for treating endodontics and periapicalitis. The length of the root canal must be accurately measured to clean the pathogenic substances in it. This study aims to present a multifrequency impedance method based on a neural network for root canal length measurement. A circuit system was designed which generates a current of frequencies from 100 Hz to 20 kHz in order to augment the data of impedance ratios with different combinations of frequencies. Several impedance ratios and other quantified characteristics, such as the type of tooth and file, were selected as features to train a neural network model that could predict the distance between the file and apical foramen. The model uses leave-one-out cross-validation, adopts the Adam optimizer and regularization, and has two hidden layers with nine and five nodes, respectively. The neural network-based multifrequency impedance method exhibits nearly 95% accuracy, compared with the dual-frequency impedance ratio method (which demonstrated no more than 85% accuracy in some situations). This method may eliminate the influence of human and environmental factors on measurement of the root canal length, thereby increasing measurement robustness.

Comparison of three different apex locators in determining the working length of mandibular first molar teeth with irreversible pulpitis compared with an intraoral periapical radiograph: A block randomized, controlled, clinical trial

AIM

The aim of the present study was to assess the clinical accuracy APEX and 0.5 marks of three different apex locators - iPex II, Root ZX, and Apex ID - before and after canal preparation in the mandibular first molar.

METHODS

Sixty patients between the ages of 13-60 years participated in the study. After access gaining and canal preparation stages files were inserted with the apex locator clip attached until the electronic apex locators (EALs) shows readings of APEX and 0.5 marks and same is confirmed with periapical radiographs. Eighteen apex locator readings were recorded from each tooth, and 1080 readings were obtained from the 60 patients.

RESULTS

Differences among readings from apex locators and radiographic readings were assessed using paired t test. Only in two patients (1 male and 1 female) were the APEX mark readings different from the radiograph estimation. When the 0.5 mark readings of three different EALs were compared with each other, we could observe that the readings from Root ZX differed significantly (P < 0.05).

CONCLUSIONS

In the present study, we observed the negligible differences in readings between the EAL at the APEX mark readings, coinciding with the radiographic observation. Clinically, we recommend the apical foramen be located with the apex locators' APEX mark readings prior to identifying the apical constriction position.

In-vivo compatibility between pacemakers and dental equipment

In-vitro studies suggest that electromagnetic interference can occur under specific conditions involving proximity between electronic dental equipment and pacemakers. At present, in-vivo investigations to verify the effect of using electronic dental equipment in clinical conditions on patients with pacemakers are scarce. This study aimed to evaluate, in vivo, the effect of three commonly used electronic dental instruments - ultrasonic dental scaler, electric pulp tester, and electronic apex locator - on patients with different pacemaker brands and configurations. Sixty-six consecutive non-pacemaker-dependent patients were enrolled during regular electrophysiology follow-up visits. Electronic dental tools were operated while the pacemaker was interrogated, and the intracardiac electrogram and electrocardiogram were recorded. No interferences were detected in the intracardiac electrogram of any patient during the tests with dental equipment. No abnormalities in pacemaker pacing and sensing function were observed, and no differences were found with respect to the variables, pacemaker brands, pacemaker configuration, or mode of application of the dental equipment. Electromagnetic interferences affecting the surface electrocardiogram, but not the intracardiac electrogram, were found in 25 (37.9%) patients, especially while using the ultrasonic dental scaler; the intrinsic function of the pacemakers was not affected. Under real clinical conditions, none of the electronic dental instruments tested interfered with pacemaker function.

Consistency of electronic measurements of endodontic working length when using multiple devices from the same manufacturer-an in vitro study

OBJECTIVES

To assess the consistency of electronic determination of endodontic working length obtained from four identical electronic root canal length measurement devices (ERCLMD) from five different types of ERCLMD each under various in vitro conditions.

MATERIALS AND METHODS

Eight extracted teeth, seven single-rooted teeth, and one molar were accessed. Root length was measured and instruments were inserted and fixed with the tip placed beyond and short of the apical constriction, in roots with an artificial perforation or an open apex. Devices tested were Root ZX (Morita, Kyoto, Japan), Dentaport ZX (Morita), Apex ID (SybronEndo, Glendora, USA), ProPex II (Dentsply Maillefer, Victoria, Australia), and Raypex 6 (VDW-Antaeos, Munich, Germany). Teeth were irrigated with different solutions (NaOCl, EDTA, CHX). ERCLMDs were connected and measurements were recorded. Consistency was classified by the scores 0-4. Comparisons were carried out using the Kruskal-Wallis test (α = 0.05). For multiple testing, the level of significance was adjusted and analysis was performed using the Mann-Whitney U test.

RESULTS

Among the five types of ERCLMD, Apex ID and Raypex 6 showed the highest consistency. There was no statistically significant difference between the settings and conditions. Raypex 6 showed the highest consistency for measurements in case of a perforation.

CONCLUSION

Different devices from one type of ERCLMD show a high consistency. Nevertheless, general statements on the accuracy of one type of ERCLMD taken from studies investigating only one device per type should be drawn with caution.

CLINICAL RELEVANCE

The study refers to the reliability and repeatability of determination of endodontic working length by using ERCLMDs.

A comparative assessment of the accuracies of Raypex 5, Raypex 6, iPex and iPex II electronic apex locators: An in vitro study

PURPOSE

The aims of this study were to examine the accuracy of iPex II and to compare it with those of Raypex 5, Raypex 6 and iPex electronic apex locators (EALs).

MATERIALS AND METHODS

Thirty fresh human mandibular premolar teeth were used in this study. Crown segments were cut and root canals were coronally flared. A #10 K-file was inserted until its tip can be seen within apical foramen to determine actual working length (AWL). Teeth were embedded in alginate and each multi-frequency EALs were randomly tested to determine the electronic working length (EWL). Differences between AWLs and EWLs were statistically compared.

RESULTS

No significant differences were found between four EALs. EWL measurements by Raypex 5 were accurate in 64.29%, Raypex 6 in 53.58%, iPex in 64.29% and iPex II in 50% of the specimens, within the range of ±0.5 mm from the AWL.

CONCLUSION

Within the limitations of this in vitro experiment, our findings indicate that the accuracy of working length measurements calculated with iPex II was similar to those of other multi-frequency EALs used in this study.

An Invitro Evaluation of the Accuracy of Two Electronic Apex Locators to Determine Working Length in the Presence of Various Irrigants

Background

Cleaning and shaping of root canal system requires various irrigating solutions. The question is whether the presence of irrigation solution alters working length determination using apex locators. The purpose of this study was to compare the accuracy of Root ZX and i-Root apex locator for determining working length in the presence of different irrigating solution.

Materials and Method

Eighty extracted single rooted human teeth were used. The teeth were sectioned at Cemento Enamel Junction (CEJ) and actual canal length determined. Then, working length measurements were obtained using Root ZX and i-Root apex locator in the presence of irrigating solutions namely 0.9% saline, 3% of sodium hypochlorite (NaOCl), 2% chlorhexidine digluconate(CHX) and 17% Ethylene Diamine Tetra Acetic acid (EDTA). The measurements obtained with Root ZX and i-Root apex locator were compared with actual canal length and subjected to statistical analysis using Post Hoc Test Tukey's Method.

Results

This study revealed that both the tested Electronic apex locators (EAL) were able to measure the canal length in the presence of tested irrigating solutions. The presence of irrigating solutions of saline, NaOCl, chlorhexidine and EDTA in the root canal marginally influenced the accuracy of the Root ZX or i-Root (P < 0.36), but with no clinical significance.

Conclusion

Root ZX and i-Root can be used safely to determine working length in the presence of various irrigants. The content of the root canal did not influence the accuracy while measuring working length using Electronic apex locators (EAL)

Comparison of apically extruded debris associated with several nickel-titanium systems after determining working length by apex locator

Background/Aim:

To compare apically extruded debris using ProTaper Universal (PTU), ProTaper Next (PTN), WaveOne (WO), Twisted File (TF), M-Two (MT), and Revo-S (RS) after determining the working length (WL) with root ZX.

Materials and Methods:

Seventy-two teeth were selected. The WL determination was performed with root ZX. The teeth were divided into six experimental groups, randomly. In groups, root canals were prepared with PTU to size F4/0.06, with PTN to size X4/0.06, with WO to size 40/0.08, with TF to size 40/0.04, with MT to size 40/0.06, and with RS to size AS40/0.06. After preparations were completed, final irrigation was performed with 2 mL distilled water, and a total of 10 mL of distilled water was used in each tooth. Tubes were stored in an incubator at 68°C for 5 days to evaporate the distilled water before weighing the dry debris. Data were analyzed by the Mann–Whitney U-test.

Results:

The RS group led to the highest amount of extruded debris, however, WO led to the least amount of extruded debris. There was no statistically difference among the groups (P > 0.05).

Conclusions:

The authors conclude that the results obtained might depend on the apex locator used to determine the WL.

Comparison of third generation versus fourth generation electronic apex locators in detecting apical constriction: An in vivo study

AIM

The aim of this in vivo study was to compare the accuracy of Root ZX and Raypex 5 in detecting minor diameter in human permanent single-rooted teeth.

MATERIALS AND METHODS

Thirty-one patients with completely formed single-rooted permanent teeth indicated for extraction were selected for the study. Crown was flattened for stable reference point and access cavity prepared. Working length was determined with both apex locators. A 15 K file adjusted to that reading was placed in the root canal and stabilized with cement. The tooth was then extracted atraumatically. Following extraction apical 4 mm of root was shaved. The position of the minor diameter in relation to the anatomic apex was recorded for each tooth under stereomicroscope at ×10. The efficiency of two electronic apex locators to determine the minor diameter was statistically analyzed using paired sample t-test.

RESULTS

The minor diameter was located within the limits of ±0.5 mm in 96.6% of the samples with the Root ZX and 93.2% of the samples with Raypex 5. The paired sample t-test showed no significant difference.

CONCLUSION

On analyzing the results of our study it can be concluded that Raypex 5 was as effective as Root ZX in determining the minor diameter.

Effect of maintaining apical patency on endodontic pain in posterior teeth with pulp necrosis and apical periodontitis: a randomized controlled trial

AIM

To evaluate the association between apical patency and post-operative pain in posterior teeth with pulp necrosis and apical periodontitis.

METHODOLOGY

Sixty-eight patients requiring primary root canal treatment in mandibular first molars with necrotic pulps and apical periodontitis were included. The patients were randomly allocated to one of two groups: patency (n = 34) and nonpatency (n = 34). After administering local anaesthesia, root canal preparation was completed using ProTaper rotary instruments. A size 10 K-file was used as a patency file and carried 1 mm beyond the working length (WL) between each instrument change in the patency group, while it was carried up to WL in the nonpatency group. Patients were asked to record their pain experience on a pain chart daily for 7 days. Three patients (two in the patency group, one in the nonpatency group) did not return with completed pain charts on the subsequent visit, resulting in a total of 65 patients for the final analysis (patency, n = 32; nonpatency, n = 33). Data was analysed using Chi Square test, t-test, Mann-Whitney test and Wilcoxon Signed Ranks test.

RESULTS

Overall, 43% of the patients experienced post-operative pain. The patency group had less incidence of pain (34%) as compared to the nonpatency group (52%), but the difference was not significant (P = 0.163).

CONCLUSION

Maintenance of apical patency during chemomechanical preparation had no significant influence on post-operative pain in posterior teeth with necrotic pulps and apical periodontitis.

In vivo accuracy of two electronic foramen locators based on different operation systems

The aim of this study was to compare in vivo the accuracy of two electronic foramen locators (EFLs) based on different operation systems - Root ZX and Propex II. Ten healthy adult patients needing premolar extractions due to orthodontic reasons participated in the study, providing a sample of 17 noncarious, non-restored, vital teeth (n= 24 canals). After coronal access preparation and cervical preflaring and prior to tooth extraction, the root canal length was measured alternating the two EFLs. All measurements were performed with K-files well fitted to the canal diameter at the level that each EFL indicated the apical foramen in their display (APEX or 0.0). The last K-file were fixed in place with cyanoacrylate, the tooth was extracted, and the apical 4 mm of each root were resected to measure the distance between the file tip and the apical foramen. The mean errors based on the absolute values of discrepancies were 0.30 ± 0.29 mm (Root ZX) and 0.32 ± 0.27 mm (Propex II). Analysis by the Wilcoxon test for paired samples showed no statistically significant differences between the electronic canal measurements performed with the EFLs (p=0.587). The apical foramen was accurately located in 75% (Root ZX) and 66.7% (Propex II) of the cases, considering a ±0.5 mm error margin, with no statistically significant difference by the chi-square test. Despite having different measurement mechanisms, both EFLs were capable of locating the apical foramen with high accuracy in vivo. Under the tested clinical conditions, Root ZX and Propex II displayed similar results.

Accuracy and repeatability of 3 apex locators in locating root canal perforations: an ex vivo study

INTRODUCTION

This study was an ex vivo evaluation of the accuracy and repeatability of 3 electronic apex locators (EALs) in locating simulated root canal perforations.

METHODS

Thirty-five human teeth were used. Perforations were placed 5 mm from the apex of each specimen. A #15 K-file was attached to a micrometer, and the specimens were fixed in a mounting model. The EALs were connected to the files, and electronic measurements of the simulated perforations were obtained. This procedure was repeated, the files were cemented in place, and x-rays were obtained to evaluate the distances between the measurement files and the simulated perforations. The obtained results were compared with the corresponding control lengths. Three investigators evaluated the distance of the file position in relation to the perforation for each specimen. The 3 investigators reached consensus regarding these measurements.

RESULTS

Statistical analyses of the results revealed that the EAL reliabilities in the exact detections of the root canal perforations were 97.1% for the Mini Apex Locator, 100% for the Root SW, and 91.4% for the Root ZX II. Analysis of variance revealed that the accuracies of the 3 devices were not different (P > .05). The results also indicated high levels of repeatability for each of the 3 EALs (intraclass correlation coefficients: 0998, 0.999, and 0.999 for the Mini Apex Locator, Root SW, and Root ZX II, respectively).

CONCLUSIONS

It was concluded that each of these 3 EALs provided excellent ex vivo accuracy in locating root perforations and that all tested devices possess excellent ex vivo repeatability.

Influence of apical periodontitis on the accuracy of 3 electronic root canal length measurement devices: an in vivo study

INTRODUCTION

The aim of this in vivo study was to evaluate the influence of apical periodontitis (AP) on the accuracy of Dentaport ZX (J Morita, Kyoto, Japan), Raypex 5 (VDW, Munich, Germany), and i-Root (S-Denti, Seoul, Korea) electronic root canal length measurement devices (ERCLMDs).

METHODS

Thirty-two single-rooted teeth scheduled for extraction, consisting of 16 teeth with AP and 16 teeth with normal periapex (NP), were selected. The access cavity was prepared, and the coronal portion of the canal was flared. The electronic working length (EWL) was determined by each ERCLMD according to each manufacturer's instructions. Each tooth was extracted, and the actual working length (AWL) was determined by inserting a size 15 K-file until the tip could be seen at a position tangential to the major foramen and then 0.5 mm was subtracted from the measurement. The distance from the file tip (EWL) to the point 0.5 mm coronal to the major foramen (AWL) was calculated. Data were analyzed using the nonparametric Fisher exact test and the chi-square test. Statistical significance was set at P < .05.

RESULTS

The accuracies of Dentaport ZX, Raypex 5, and i-Root within ± 0.5 mm in the AP group were 93.8%, 81.3%, and 75.0%; they were 93.3%, 86.7%, and 73.3% in the NP group, respectively. There were no significant differences between the accuracy of each device in the 2 groups (P > .05). Considering the 2 groups of AP and NP, there were no statistically significant differences in the accuracy of the ERCLMDs (P > .05).

CONCLUSIONS

The presence of AP did not influence the accuracy of ERCLMDs.

An in vivo evaluation of different methods of working length determination

OBJECTIVE

The purpose of this in vivo study was to compare the ability of digital tactile, digital radiographic and electronic methods to determine reliability in locating the apical constriction.

MATERIALS AND METHODS

Informed consent was obtained from patients scheduled for orthodontic extraction. The teeth were anesthetized, isolated and accessed. The canals were negotiated, pulp chamber and canals were irrigated and pulp was extirpated. The working length was then evaluated for each canal by digital tactile sensation, an electronic apex locator (The Root ZX) and digital radiography. The readings were then compared with post-extraction working length measurements.

RESULTS

The percentage accuracy indicated that EAL method (Root ZX) shows maximum accuracy, i.e. 99.85% and digital tactile and digital radiographic method (DDR) showed 98.20 and 97.90% accuracy respectively.

CLINICAL SIGNIFICANCE

Hence, it can be concluded that the EAL method (Root ZX) produced most reliable results for determining the accurate working length.

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.

In vivo accuracy of three electronic root canal length measurement devices: Dentaport ZX, Raypex 5 and ProPex II

AIM

To compare in vivo three different electronic root canal length measurement devices: Dentaport ZX, Raypex 5 and ProPex II.

METHODOLOGY

Thirty single-rooted permanent teeth scheduled for extraction because of periodontal disease were selected from 10 adult patients (ranging from 45 to 67 years) and divided into three groups of 10 teeth. Before the extraction, an access cavity was prepared and the crown was adjusted to establish a stable reference point for all measurements. The working length in Group 1 was determined using the Dentaport ZX apex locator. A K-file with the largest diameter that could reach the last green bar on the screen was stabilized in the canal using a dual-curable flow resin composite. The same procedure was used for the Raypex 5 (the file reached the last yellow bar) and Propex II (0.0 orange bar) apex locators. The teeth were then extracted and cleared. The distance between the tip of the file and the major foramen was then calculated for each tooth using digital photography according to Axiovision AC software (Carl Zeiss). Positive values were assigned when the file tip passed beyond the major foramen, negative values when the tip was short of the foramen and zero value when the file tip and the foramen coincided. Statistical analysis was performed using the chi-squared test or Fisher's exact test (P ≤ 0.05).

RESULTS

  Dentaport ZX, Raypex 5 and ProPex ΙΙ produced, respectively, 6, 2 and 4 out of 10 correct measurements, 0, 6 and 5 long measurements and 4, 2, and 1 short measurements. The differences between the three electronic root canal length measurement devices were not significant (P = 0.507).

CONCLUSIONS

Under the in vivo conditions of this study, the three electronic root canal length measurement devices were not significantly different in terms of locating the major foramen.

Ex vivo accuracy of three electronic apex locators using different apical file sizes

This study evaluated the accuracy of three electronic apex locators (Root ZX, Novapex, and Justy II) in root canal length determinations using different apical file sizes, considering the apical constriction (AC) and the major foramen (MF) as anatomic references. The diameter of the apical foramina of 40 single-rooted teeth was determined by direct visual measurement and the master apical file was established. Electronic measurements were then performed using 3 instruments: the selected master apical file (adjusted file), one size smaller (intermediate file), and two sizes smaller (misfit file). The distances from the tip of files fixed in the canals to the MF and to the AC were measured digitally. Precision at AC and at MF for the misfit, intermediate and adjusted apical files was as follows: 80%/88%/83% and 78%/83%/95% (Root ZX); 80%/85%/80% and 68%/73%/73% (Novapex); and 78%/80%/78% and 65%/78%/70% (Justy II). Considering the mean discrepancies, statistically significant differences were found only for the adjusted file at MF, with Root ZX presenting the best results at MF. The chi-square test showed significant differences between the acceptable measurements at AC and at MF for the Justy II and Novapex (± 0.5 mm) regardless of file adjustment. Under the conditions of the present study, all devices provided acceptable electronic measurements regardless of file adjustment, except for Root ZX which had its performance improved significantly when the precisely fit apical file was used. Justy II and Novapex provided electronic measurements nearest to the AC.

Accuracy of Root ZX II in locating foramen in teeth with apical periodontitis: an in vivo study

INTRODUCTION

This study was conducted in vivo to investigate the accuracy of Root ZX II in locating the apical foramen in teeth with apical periodontitis (AP).

METHODS

Twenty-seven single-root teeth scheduled for extractions were selected; in AP group, there were 12 teeth with pulp necrosis and radiographic evidence of apical lesions, and VT group consisted of 15 vital teeth. After endodontic access, the coronal portion of the canal was flared, and electronic measurement was performed by using a 15 K-file until the device level reading "APEX" was reached. The file was fixed in place, and the tooth was extracted. The apical third of the root was shaved until exposure of the file. The distance from the file tip to the most coronal border of the apical foramen was obtained.

RESULTS

The mean distance in AP group was +0.117 (standard deviation, 0.373) and in VT group was -0.105 (standard deviation, 0.218). The unpaired t test showed no difference between the groups when comparing the mean distances (P > .05). The apical foramen was accurately located within ±0.5 mm in 83% of the teeth in AP group and in 100% of VT group. Statistical analysis showed no difference between the groups (P = .1092).

CONCLUSIONS

The Root ZX II device was accurate in locating the apical foramen regardless of the presence of AP.

Clinical reproducibility of three electronic apex locators

AIM

To compare the reproducibility of three electronic apex locators (EALs), Dentaport ZX, RomiApex A-15 and Raypex 5, under clinical conditions.

METHODOLOGY

Forty-eight root canals of incisors, canines and premolars with or without radiographically confirmed periapical lesions required root canal treatment in 42 patients. In each root canal, all three EALs were used to determine the working length (WL) that was defined as the zero reading and indicated by 'Apex', '0.0' or 'red square' markings on the EAL display. A new K-file of the same size was used for each measurement. The file length was fixed with a rubber stop and measured to an accuracy of 0.01 mm. Measurements were undertaken by two calibrated operators. Differences in zero readings between the three EALs in the same root canal were statistically analysed using paired t-tests with the Bonferroni correction, Bland-Altman plot and Linn's concordance correlation coefficients at α = 0.05.

RESULTS

Mean and standard deviation values measured by the three EALs showed no statistically significant differences. Identical readings by all three EALs were found in 10.4% of root canals. Forty-three per cent of readings differed by less than ± 0.5 mm and 31.3% exceeded a difference of ± 1 mm.

CONCLUSIONS

The clinical reproducibility of Dentaport ZX, RomiApex A-15 and Raypex 5 was confirmed with the majority of readings within the ± 1.0 mm range. However, the small number of identical zero readings suggests that EALs are not reliable as the sole means of WL determination under clinical conditions.

In vivo assessment of the impedance ratio method used in electronic foramen locators

BACKGROUND

The results of an in vivo study on the "ratio method" used in electronic foramen locators (EFL) are presented. EFLs are becoming widely used in the determination of the working length (WL) during the root canal treatment. The WL is the distance from a coronal reference point to the point at which canal preparation and filling should terminate. The "ratio method" was assessed by many clinicians with the aim of determining its ability to locate the apical foramen (AF). Nevertheless, in vivo studies to assess the method itself and to explain why the "ratio method" is able to locate the apical foramen and is unable to determine intermediate distances were not published so far.

METHODS

A developed apparatus applies an electrical current signal with constant amplitude of 10 μARMS through the endodontic file within the root canal. The applied current signal is composed by summing six sine waves, from 250 Hz to 8 kHz. Data were acquired with the endodontic file tip at 7 different positions within root canals. In the frequency domain the quotients between the amplitude of a reference frequency and the amplitudes of the other frequencies components were calculated. Twenty one root canals were analyzed in vivo, during the endodontic treatment of twelve teeth of different patients, with age between 20 to 55 years.

RESULTS

For the range of frequencies used in the commercial EFLs and for distances ranging from -3 mm to -1 mm of the AF, the impedance of the root canal is mainly resistive. However, when the file tip gets closer to AF, the root canal electrical impedance starts to change from a mainly resistive to a complex impedance. This change in the measured root canal impedance starts when the file tip is near -1.0 mm from the AF, getting stronger as the file tip gets closer to the AF. This change in the impedance behavior affects the ratio (quotient) of the impedance measured at different frequencies. Through graphic analysis it is demonstrated why EFLs based on the ratio method are unable to accurately measure any distances between - 3.0 and -0.5 mm from the apical foramen. The only reliable measurement is the 0 mm distance, which is when the file tip is at the AF.

CONCLUSIONS

The electrical impedance values of 21 root canals were in vivo studied. The results confirm the ability of EFLs that are based on the ratio method to accurately locate the AF position and explain why they are unable to determine the file tip position along the root canal.

Ex vivo evaluation of the accuracy and coefficient of repeatability of three electronic apex locators using a simple mounting model: a preliminary report

AIM

To compare ex vivo the accuracy and coefficient of repeatability of three electronic apex locators in locating the apical constriction.

METHODOLOGY

Thirty-one single-rooted teeth were used. The teeth were sectioned at the cement--enamel junction. A mounting model was used for the measurement of electronic length (EL). The Root ZX-II, the Mini Apex Locator and the Novapex were used for electronic measurements. Each electronic measurement was obtained and repeated. After the last measurement, the file was cemented in place, and the apical 4 mm of each root canal was exposed. The distance from the tip of the file to the apical constriction was determined by three investigators and compared with the corresponding ELs.

RESULTS

The coefficient of repeatability of all devices was acceptable: Root ZX-II, 0.04 mm; Mini Apex Locator, 0.10 mm; and Novapex, 0.08 mm. There was little variation in inter-examiner agreement; the rho(C) (Lin) correlation coefficient was 0.83 for examiners 1 and 2, 0.88 for examiners 1 and 3 and 0.99 for examiners 2 and 3. Using the Root ZX-II, 13 of 31 electronic measurements were located at the apical constriction (42%). Otherwise, the tip of the file was not located at the apical constriction in any of the electronic measurements with the other two devices. The Wilcoxon signed rank test did not reveal any statistical difference between the Root ZX-II measurements and the actual length (P = 0.628), but there was a statistical difference between the Mini Apex Locator and Novapex measurements and the actual length position (P < 0.05).

CONCLUSIONS

The devices tested in this study had a high coefficient of repeatability. The Root ZX-II was accurate, but the Mini Apex Locator and Novapex were not accurate in locating the apical constriction.

In vivo comparison of the accuracy of two electronic apex locators

The aim of this study was to analyse in vivo the accuracy of two apex locators, Root ZX and Novapex, to determine the position of the apical constriction. Twenty-three human single-rooted teeth to be extracted for periodontal reasons constituted the experiment. Endodontic access was obtained and the apical constriction was determined by one of the apex locators after initial crown-down preparation. When the electronic marker indicated that the tip of the endodontic file was at the apical constriction, the teeth were filled with composite and then surgically removed. The presence of the endodontic file tip at the apical constriction was evaluated stereomicroscopically (30×) and confirming radiographs were exposed. The accuracy of Root ZX and Novapex was 91.7% and 81.8% respectively. Within the limits of this study, the evaluated apex locators have a similar clinical performance for the apical constriction location.

Influence of preflaring on the accuracy of length determination with four electronic apex locators

INTRODUCTION

The aim of this study was to compare the influence of preflaring on the accuracy of 4 electronic apex locators (EALs): Root ZX, Elements Diagnostic Unit and Apex Locator, Mini Apex Locator, and Apex DSP.

METHODS

Forty extracted teeth were preflared by using S1 and SX ProTaper instruments. The working length was established by reducing 1mm from the total length (TL). The ability of the EALs to detect precise (-1mm from TL) and acceptable (-1+/-0.5 mm from TL) measurements in unflared and preflared canals was determined.

RESULTS

The precise and acceptable (P/A) readings in unflared canals for Root ZX, Elements Diagnostic Unit and Apex Locator, Mini Apex, and Apex DSP were 50%/97.5%, 47.5%/95%, 50%/97.5%, and 45%/ 67.5%, respectively. For preflared canals, the readings were 75%/97.5%, 55%/95%, 75%/97.5%, and 60%/87.5%, respectively. For precise criteria, the preflared procedure increased the percentage of accurate electronic readings for the Root ZX and the Mini Apex Locator (P < .05). For acceptable criteria, no differences were found among Root ZX, Elements Diagnostic Unit and Apex Locator, and Mini Apex Locator (P > .05). Fisher test indicated the lower accuracy for Apex DSP (P < .05).

CONCLUSIONS

The Root ZX and the Mini Apex Locator devices increased significantly the precision to determine the real working length after the preflaring procedure. All the EALs showed an acceptable determination of the working length between the ranges of+/-0.5mm except for the Apex DSP device, which had the lowest accuracy.