Evaluation of the Accuracy of Electronic Apex Locators in Modern Endodontics: An Umbrella Review.

Background and Objectives: To achieve success in endodontic treatment, it is essential to properly perform the steps of shaping, cleansing and obturation. Determining the working length of the canal is, therefore, a process that must be precise and accurate. Electronic apex locators are a useful tool for the clinician to best perform this step of endodontic treatment. Materials and Methods: The purpose of the following umbrella review is to evaluate, through data in the literature, the degree of accuracy of apex locators. Results: Seven systematic reviews were included in the following umbrella review. Five compare the accuracy of apex locators versus radiographic techniques, two compare different types of electronic apex locators, and two analyze the determination of working length in primary teeth. Conclusions: From the results obtained from the following umbrella review, albeit at low levels of evidence, the methods for determining working length using electronic apex locators and other methods, particularly using radiographic evaluation, are equally valid.

Accuracy of Working Length Measurement Using Cone Beam Computed Tomography at Three Field of View Settings, Conventional Radiography, and Electronic Apex Locator: An Ex-vivo Study.

OBJECTIVES: Determining the working length (WL) in root canal treatment facilitates the treatment prognosis. The introduction of apex locators and new CBCT devices in dentistry influenced this consideration. This comparative study evaluated the accuracy of working length measurement by cone-beam computed tomography (CBCT) in three fields of view (FOVs), conventional radiography, and the apex locator Raypex 5. METHODOLOGY: The descriptive-analytical study was performed on 40 lower premolar teeth that met the inclusion criteria. Direct observation under the microscope was considered the gold standard and compared with measurements by the electronic apex locator, CBCT, and periapical images. RESULTS: The results were analyzed by paired t-tests and Wilcoxon tests. A significance level of 0.05 was considered in this study. CBCT 5×5 FOV with a p-value of 0.733 and analog radiography with a p-value of 0.001 achieved the working lengths with the highest and lowest accuracy, respectively. In addition, the difference between actual and measured working length using analog radiography was significant (p-value <0.05). CONCLUSIONS: According to the results of this study, CBCT images at different FOVs and those taken by the apex locator Raypex 5 can be used as a reliable method for estimating the working length. (EEJ-2023-10-141).

Clinicians' perspectives, inducements, preferences, and clinical experiences regarding the use of electronic apex locator and apex locator integrated engine-driven instrumentation: a cross-sectional study.

BACKGROUND: This study aimed to investigate the perspectives, preferences, and clinical experiences regarding using electronic apex locator and apex locator integrated instrumentation of dentists and endodontists. METHODS: A web-based questionnaire consisting of 3 parts and 23 closed-ended questions to achieve the objective of the study was carried out in ethical conditions between August and October 2023. The first part of survey included demographic information, while the second part was about evaluating electronic apex locator usage. In the last part, only participants' use of apex locator-integrated instrumentation was evaluated. Data were analyzed at a significance level of p < 0.05. RESULTS: A total of 297 clinicians, including 59 endodontists and 34 endodontic residents/Ph.D. students participated in the questionnaire. Endodontists and endodontic residents/Ph.D. students perform statistically significantly more root canal treatments per week on average (p = 0.001). For the working length determination method (multiple option question), 78.5% of participants use an electronic apex locator and 39.7% apex locator-integrated engines. However, the preference rate for electronic apex determination technique was generally 95.6%, with the full rate confirmation of endodontists and endodontic residents/Ph.D. students (100%). A total of 21 endodontists out of 59 prefer apex locator integrated engine-driven instrumentation. Although many of these specialized clinicians use this technique, they stated that they measure electronic working length passively for confirmation of the working length before (90.5%) and after the preparation (66.7%). CONCLUSIONS: Dentists, as well as endodontists, are skeptical about apex locator-integrated engine-driven instrumentation. Using this technique as a supporter rather than a primary way for preparation within safe limits may give safer results in terms of treatment outcomes.

Comparative evaluation of the accuracy of electronic apex locators and cone-beam computed tomography in detection of root canal perforation and working length during endodontic retreatment.

BACKGROUND: To evaluate the accuracy of the electronic apex locators (EALs), and Cone-Beam Computed Tomography (CBCT) scanning, both in working length (WL) determination and in the detection of root canal perforations in retreatment cases. METHODS: Sixty human mandibular premolars were selected. After crown removal partially and canal access, root canals were instrumented and irrigated. The obturation process utilized gutta-percha and sealer with warm vertical compaction. Two groups were distinguished: one without perforation (Group 1) and the other with an apical third perforation (Group 2). Retreatment included filling removal, apical preparation, and irrigation. Actual working lengths (AWL) were determined using a stereomicroscope. CBCT images were used to measure CBCT working length (CWL), with adjustments for optimal views. Propex II and Dentaport ZX were used to measure electronic working length (EWL). Differences between EWL and AWL, as well as CWL, were analyzed to gauge accuracy. Data underwent Two-way ANOVA analysis. Measurements within ± 0.5 and ± 1 mm tolerance ranges were deemed successful for each device, followed by applying the Pearson Chi-square test. RESULTS: The study reveals no significant inter-group variations in device performance (p > .05). Dentaport ZX missed detecting perforation in two Group 2 (apical perforation) cases. For ± 1 mm tolerance, Propex II displayed the highest success in Group 2 (apical perforation). CONCLUSION: This study demonstrates the comparable performance of Propex II, Dentaport ZX, and CBCT in endodontic retreatment, providing insights into diagnostic reliability.

The usefulness of ultrasonography as a dynamic measurement system for visualizing root canal working length: an in vivo study.

OBJECTIVE: Although apex locators are generally effective tools for determining root canal working length, they may produce inaccurate results in some cases. The present study aimed to evaluate the efficacy of ultrasonography as an alternative method for measuring root canal length. MATERIALS AND METHODS: Forty-seven anterior teeth with apical lesions were selected for the study. Initially, an electronic apex locator was used to measure the working length. Subsequently, ultrasonography was employed to visualize the root apex and determine the working length. During ultrasound imaging, a K-file No. 15 was inserted into the root canal until its tip was visible on the ultrasound monitor. Measurements obtained from both methods were compared using an independent sample t-test. Correlations were assessed with the Pearson correlation coefficient, and agreement was determined using the Bland‒Altman plot. RESULTS: The mean working canal length was 19.9 mm for the apex locator and 20.6 mm for the ultrasonography-guided method. No significant differences were observed between the data obtained using the apex locator method and the data obtained using the ultrasonography guidance method. Furthermore, a high level of agreement was identified between the two techniques. CONCLUSION: Ultrasonography can be used to visualize the apex effectively and determine canal length, especially when canal length determination is uncertain for various reasons.

In vitro evaluation of the accuracy of electronic apex locators and cone-beam CT in the detection of oblique root fractures.

OBJECTIVES: This study aimed to compare the accuracy of cone-beam CT (CBCT) scanning and 3 different electronic apex locators (EALs) in the detection of simulated oblique root fractures (ORF) in different localizations. METHODS: The study utilised a total of 80 human maxillary incisors, which were categorised into two groups based on the location of the ORF (apical and middle third of the root) formed on the buccal side of the root surface. The measurement of the distance between the incisal edge and the intersection of the ORF with the root canal was conducted using a stereomicroscope. This measurement is referred to as the actual working length (AWL). Additionally, three EALs-Dentaport ZX, EndoRadar Pro, and Propex II-were utilised to determine the electronic working length (EWL). Furthermore, CBCT images were employed to assess the distance, known as the CBCT working length (CWL). The differences were determined by subtracting AWL from EWL and CWL. RESULTS: Based on the accuracy of the devices, there were no significant differences observed among Dentaport ZX, EndoRadar, Propex II, and CBCT measures in both the apical and middle third ORF groups, within the acceptable range of 0.5 and 1 mm. CONCLUSIONS: The accuracy of Dentaport ZX, Propex II, and CBCT was higher in the middle third ORF group compared to the apical third ORF group, with a tolerance of 0.5 mm. However, there were no significant differences seen among the devices.

Accuracy of Working Length Determination - Electronic Apex Locator Versus Cone Beam Computed Tomography

ABSTRACT Objective: To compare the accuracy of working length determination between cone beam computed tomography (CBCT) and electronic apex locator by measuring the actual working length of teeth. Material and Methods: A total of 150 single-rooted tooth assessed by radiograph undergoing root canal therapy were selected. The process was repeated to obtain a buccolingual and mesiodistal section of all teeth. The measurement line was considered from the reference occlusal plane following the center of the canal to the terminus. All information regarding the accuracy of cone-beam computed tomography and apex locator was noted in a pre-designed proforma. Results: CBCT consistently demonstrated high accuracy across all tooth types in both jaws. The electronic apex locator exhibited varying precision, with greater accuracy observed in the mandible. Statistical analyses revealed significant differences in electronic apex locator accuracy among tooth types in the maxilla (p=0.042), emphasizing the importance of specific clinical considerations. Conclusion: Cone beam computed tomography emerges as a reliable diagnostic tool for accurate working length determination, especially in complex cases, while the electronic apex locator remains valuable with careful consideration of potential variations in accuracy. An individualized approach, considering tooth type, jaw location, and clinical context, is crucial for precise working length determination in endodontic practice.

Evaluation of Different Techniques of Working Length Determination in Comparison with CBCT.

AIM: To estimate the working length of teeth using conventional tactile technique, radiovisiography technique, Apex locator, and confirmation of working length by cone beam computed tomography technique. MATERIALS AND METHODS: Forty patients with the age group between 20 and 50 years with irreversible pulpitis were included in this study. After taking a preoperative radiograph, the procedure was started. The cavity wall buildup was done using composite in the cases needed and then rubber dam application was done. The working length of mesiobuccal and mesiolingual canal was taken using cone beam computed tomography and this was considered as the standard value. Then using tactile method, length of the canal was measured using radiovisiographic software followed by apexlocator. RESULT: The Apex locator has showed best result as compared to tactile and radiovisiography. CONCLUSION: Apex locator values were closest to cone beam computed tomography working length measurement values and electronic apexlocator can be used efficiently as an alternative method for working length determination. The quality of various techniques according to ranks of working length determination was found to be Cone beam computed tomography (CBCT) > Apexloc > Radiovisiography (RVG) > Tactile. Thus, Apex locator can be used as an alternative to cone beam computed tomography for working length determination.

Endodontic length measurements using cone beam computed tomography with dedicated or conventional software at different voxel sizes.

The aim of this study is to investigate the accuracies and the agreements of the 3D Endo software, conventional CBCT software Romexis Viewer at three voxel sizes, and the EAL ProPex Pixi in endodontic length measurements. Three hundred and twenty-nine root canals in 120 intact human extracted molars were accessed. The actual lengths (AL) and electronic lengths (EL) were measured using the ruler and electronic apex locator (EAL), respectively. Teeth were scanned using the CBCT at different voxel sizes (0.075, 0.10, and 0.15 mm). Root canal lengths were measured using 3D Endo with proposed length (3D-PL) by software, corrected length (3D-CL), Romexis Viewer. The Fisher's exact test, paired t-test and Bland-Altman plots were calculated to detect the agreements of the four methods with AL measurements. The ProPex Pixi measurements obtained the highest accuracy in the range of ± 0.5 mm. There was agreement between the 3D-PL and the 3D-CL with AL measurements at voxel size of 0.15 mm and at voxel size of 0.10 mm, respectively. The CBCT Romexis Viewer measurements agreed with AL at three voxel sizes. The conventional CBCT measurements using Romexis Viewer and dedicated software did not reach to the 100% accuracy in the range of ± 0.5 mm.

Accuracy of Four Electronic Apex Locators During Root Canal Length Determination / Precisión de Cuatro Localizadores de Ápice en la Determinación de la Longitud de Trabajo

ABSTRACT: The apical limit of tooth roots for instrumentation and obturation is a controversial subject due to the high morphological complexity presented by the apical zone of the root. The development of electronic apex locators (EALs) has made working length (WL) determination more predictable, producing more accurate results; however, the interpretation mechanisms of different devices may affect measurements taken under different clinical conditions. One hundred premolars were used to compare the effectiveness of Propex II, Raypex 6, Propex Pixi and Root ZX II in locating the apical foramen (AF). No statistically significant differences were observed when the accuracy of measurement was compared between the different groups of EALs, however Root ZX II and Raypex 6 presented the best overall performance.

RESUMEN: El límite apical radicular para la instrumentación y obturación es un tema controversial, debido a la alta complejidad morfológica que presenta la zona apical de la raíz. El desarrollo de localizadores de ápice electrónicos (EALs) ha hecho la determinación de la longitud de trabajo (WL) más predecible y con resultados más precisos. Sin embargo, el mecanismo de interpretación de cada dispositivo puede afectar la determinación de las mediciones en diferentes condiciones clínicas. Cien premolares fueron utilizados para comparar la efectividad de Propex II, Raypex 6, Propex Pixi y Root ZX II en localizar el foramen apical (AF). No se observaron diferencias estadísticamente significativas cuando se comparó la precisión de medición entre los diferentes grupos de EALs, sin embargo, Root ZX II y Raypex 6 mostraron un mejor desempeño global.

The influence of two forms of chlorhexidine on the accuracy of contemporary electronic apex locators.

BACKGROUND: Accurate determination of working length (WL) is crucial for the success of endodontic therapy. The aim of this study was to determine the influence of 2% chlorhexidine digluconate solution, 2% chlorhexidine digluconate gel and 2% hypochlorite solution on the accuracy of two devices: the Raypex 5 and the ApexDal. METHODS: Twenty-nine single-rooted human teeth were used in this study. The crowns were cut horizontally and embedded in an alginate mass. In each tooth, six endodontic measurements were made using two electronic apex locators (EALs): a Raypex 5 and an ApexDal. For each EAL, measurements were taken with the following products: 2% chlorhexidine solution (CHX-S group), 2% chlorhexidine gel (CHX-G group) and 2% NaOCl (NaOCl group). After performing an endodontic measurement, the endodontic instruments were stabilized with flow resin composite. Afterwards, the roots were removed from the alginate mass, and the apical one-third of each root was cut lengthways to recover the canal system. Last, the distance between the file tip and the apical foramen was measured under a microscope at 60 x magnification. RESULTS: Statistically significant differences were found between CHX-S and NaOCl and CHX-G and NaOCl, but no significant differences were detected between CHX-S and CHX-G during the testing of both devices. No statistically significant differences were observed between the Raypex 5 and ApexDal for all intracanal media tested. CONCLUSION: The EALs Raypex 5 and ApexDal had higher accuracy in the anatomical foramen of the root containing chlorhexidine in the gel or in the solution form than in the canal containing sodium hypochlorite.

The Reliability and Validity of the Measurements in Unilateral Cleft Lip and Palate Laser Scanned 3D Dental Casts

Abstract Objective: To evaluate the reliability and validity of the Next Engine 3D Laser scanner. Material and Methods: A total of 30 dental casts of unilateral cleft lip and palate (UCLP) children with 90 linear variables were measured using digital caliper while the laser-scanned 3D dental casts (LS3DM) were measured using Mimics Software. All scanned data coordinates (in x, y, z) were transferred into Mimics software in STL format to be measured. All the variables were measured using a computer mouse accurate to 0.5 mm. The intra-class correlation coefficient (ICC) was used to evaluate the intra- and inter-examiner reliabilities and also for the validity of two methods Results: Intra-examiner reliabilities of digital caliper and LS3DM were found excellent (ICC 0.916-0.995) and inter-examiner reliabilities of LS3DM were good to excellent (ICC 0.816-0.990). The validity of LS3DM measurements was confirmed based on the ICC values were in the range of 0.913-0.996. The overall time frame for conducting measurements was shorter using a laser-scanned model (10 min.) than using a digital caliper (5 hours) Conclusion: The LS3DM is a valid reliable tool for future high impact research in our institution.

Accuracy of CBCT-based root canal length predetermination using new endodontic planning software compared to measurements performed with an electronic apex locator ex vivo.

OBJECTIVE: To evaluate the accuracy of the new endodontic planning software (3D Endo Dentsply Sirona) based on cone beam computed tomography (CBCT) to predetermine root canal lengths compared with measurements performed with an electronic apex locator (Raypex 6; VDW) ex vivo. MATERIALS AND METHODS: CBCT scans of forty extracted human maxillary (n = 20) and mandibular (n = 20) molars were taken, and root canal lengths were predetermined with the 3D Endo software using the apical foramen (AF) and the adjoining cusp as references. Root canal lengths were determined with the Raypex 6 using the same references. To evaluate the accuracy, absolute differences between both methods and the actual root canal length (gold standard) were calculated and statistically analyzed. RESULTS: Differences between lengths measured with the 3D Endo and the Raypex 6 compared with the gold standard showed no significant differences (P = 0.879). Mean differences were 0.37 mm versus 0.35 mm in the maxillary molars, and 0.30 mm versus 0.31 mm in the mandibular molars. A total of 75.8% (3D Endo) and 79.1% (Raypex 6) of all measurements were within the limits of ± 0.5 mm. Both methods showed a tendency to result in short measurements (P < 0.001). CONCLUSIONS: Within the limitations of this study, the 3D Endo software enables an accurate three-dimensional (3D) predetermination of root canal lengths.

A Micro-computed Tomographic Evaluation of the Accuracy of 3 Electronic Apex Locators in Curved Canals of Mandibular Molars.

INTRODUCTION: This study evaluated the accuracy of 3 electronic apex locators (EALs) (CanalPro [Coltene-Endo, Cuyahoga Falls, OH], Apex ID [SybronEndo, Glendora, CA], and Root ZX Mini [J Morita, Tokyo, Japan]) in curved mesial canals of extracted mandibular molars using micro-computed tomographic (micro-CT) scanning. METHODS: The root canal length and the actual working length of 58 canals were measured using the visual method and 3-dimensional micro-CT reconstructions. The measurements of the EALs at marks "APEX/0.0" and "0.5 mark" were recorded as the electronic root canal length and the electronic working length, respectively. The absolute mean values and the percentages of distribution of the electronic measurements were compared with the actual lengths of the canals. The presence of isthmuses, accessory canals, foramen position, and the distance between the apical constriction and the apical foramen were recorded from the micro-CT scans, and their correlation to the accuracy of the EALs was determined. RESULTS: All electronic measurements showed high agreement with their respective gold standard, except the electronic root canal length of the Apex ID (P < .05). No difference in the percentage of precise measurements (within the ±0.5 mm) was found among the devices (χ2 and z tests, P > .05). Of the anatomic parameters evaluated, the presence of a lateral foramen negatively affected the 0.0 mark of the Apex ID (Wilcoxon test, P < .05). CONCLUSIONS: The Root ZX Mini and CanalPro were precise for both root canal length and working length determination in mesial curved canals of mandibular molars, whereas the Apex ID was accurate for the working length when using the 0.5 mark.

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.

Evaluation of Teeth Development in Unilateral Cleft Lip and Palate Patients in Mixed Dentition by Using Medical Image Control Systems.

OBJECTIVES: The aim of this study was to evaluate the crown and root development in patients with cleft lip and palate using medical software programmes. MATERIALS AND METHODS: In our study, 25 patients with mixed dentition unilateral cleft lip and palate were examined with cone-beam computed tomography (CBCT). The tomography images obtained as high resolution medical images on the computer control system (MIMICS 15.0, Materialise, Leuven, Belgium and SOLIDWORKS 2014 Premium, Concord, Massachusetts) were converted to three-dimensional volumetric images. These three-dimensional images of the cleft on the sides of the teeth in the crown and root growth were measured by mesiodistal length and crown/root rate with volume and area. These measurements were compared with a control group of healthy individuals. RESULTS: There were no statistically significant differences in the volume, surface area and MD size, crown/root ratio of central incisor, canine, first premolar and second premolar teeth within defect, and healthy teeth. However, it was found that there was a significant difference between the volume, surface area and MD size, and crown/root ratio of the lateral teeth in each group. CONCLUSION: In particular, among patients with cleft lip and palate, on obtaining a solid model of the tooth structure by using these programs, tooth development can be examined in more detail, diagnosis can be made more reliable, as well as in treatment planning. We believe that these programs can be used to resolve certain limitations such as a lack of an application to be used in routine dental treatment and in particular the need to do more study.

Comparison of Four Electronic Apex Locators in Detecting Working Length: An Ex Vivo Study.

AIM: To compare the accuracy of four different electronic apex locators (EALs) in detecting a position 0.5 mm short of the major foramen. MATERIALS AND METHODS: The actual working length of thirty-five extracted human teeth was determined visually as 0.5 mm short of the apical foramen. After actual working length measurements, electronic working length was measured with four different EALs (Apex Pointer+, Raypex 5, Apex ID, and Raypex 6). Measurements were repeated three times by different operators. The data were analyzed using the intraclass correlation coefficient (ICC), the repeated measure analysis of variance (rANOVA) and Bonferroni post hoc tests. The significance level was set at p < 0.05. RESULTS: The mean differences between electronic and actual working length were-0.305 mm, 0.098 mm, 0.037, and 0.144 mm for the Apex Pointer+, the Raypex 5, the Apex ID, and the Raypex 6, respectively. Multiple paired comparisons (Bonferroni test) also showed the Apex Pointer+ is significantly different from the Raypex 5, Apex ID and Raypex 6 (p = 0.000, p = 0.001, and p = 0.001 respectively). CONCLUSION: All EALs showed an acceptable determination of the working length between the ranges of ± 0.5mm except for the Apex Pointer+ device, which had the lowest accuracy. Further studies may be beneficial especially to better evaluate the accuracy of the Apex Pointer+. CLINICAL SIGNIFICANCE: This article shows that Apex ID, which has only recently been introduced into the market, showed an acceptable determination of the working length. Its accuracy was similar to that of Raypex 5 and 6.

The reliability and validity of measurements of human dental casts made by an intra-oral 3D scanner, with conventional hand-held digital callipers as the comparison measure.

AIM: Intra-oral 3D scanning of dentitions has the potential to provide a fast, accurate and non-invasive method of recording dental information. The aim of this study was to assess the reliability of measurements of human dental casts made using a portable intra-oral 3D scanner appropriate for field use. METHOD: Two examiners each measured 84 tooth and 26 arch features of 50 sets of upper and lower human dental casts using digital hand-held callipers, and secondly using the measuring tool provided with the Zfx IntraScan intraoral 3D scanner applied to the virtual dental casts. The measurements were repeated at least one week later. Reliability and validity were quantified concurrently by calculation of intra-class correlation coefficients (ICC) and standard errors of measurement (SEM). RESULTS: The measurements of the 110 landmark features of human dental casts made using the intra-oral 3D scanner were virtually indistinguishable from measurements of the same features made using conventional hand-held callipers. The difference of means as a percentage of the average of the measurements by each method ranged between 0.030% and 1.134%. The intermethod SEMs ranged between 0.037% and 0.535%, and the inter-method ICCs ranged between 0.904 and 0.999, for both the upper and the lower arches. The inter-rater SEMs were one-half and the intra-method/rater SEMs were one-third of the inter-method values. CONCLUSION: This study demonstrates that the Zfx IntraScan intra-oral 3D scanner with its virtual on-screen measuring tool is a reliable and valid method for measuring the key features of dental casts.

Ex vivo investigation on the postoperative integrity of the apical constriction after the sole use of electronic working length determination.

AIM: The present study investigated the accuracy of root canal preparation with regard to the integrity of the apical constriction (AC) using two different working length determination approaches: (1) the electronic method of working length determination (EWLD), and (2) the radiologic "gold standard" method (GS). METHODOLOGY: Simulation models were constructed by arranging extracted human teeth by means of silicon bolstered gingiva masks, along with a conductive medium (alginate). Electronic working length determination (group 1; EWLD) and radiologic plus initial electronic working length determination for posterior comparability (group 2; GS) preceded manual root canal preparation of teeth in both groups. Master cones were inserted according to working lengths obtained from the group specific method. Subsequently, root apices (n=36) were longitudinally sectioned using a diamond-coated bur. The distance between the achieved apical endpoint of the endodontic preparation and the apical constriction (AC) was measured using digital photography. Then, distances between radiologically identified apical endpoints and AC (GS-AC) were compared with the corresponding distances EWLD-AC. Moreover, the postoperative status of the AC was examined with regard to both preparation approaches. RESULTS: Differences between distances GS-AC and EWLD-AC were not statistically significant (p >0.401) (Mann-Whitney-U). Among EWLD samples, 83% of the master cones exhibiting tugback at final insertion terminated close to the apical constriction (±0.5 mm), and no impairment of the minor diameter's integrity was observed. CONCLUSIONS: The sole use of EWLD allowed for a high accuracy of measurements and granted precise preparation of the apical regions.

Comparison of four electronic root canal length measurement devices.

OBJECTIVE: The objective of this study is to evaluate the performance of four electronic root canal length measurement devices (ERCLMDs) [Root ZX, Raypex 6, ProPex II, and VDW Gold with ERCLMD] in wet and dry root canals with different major foramen diameters, in association with three file positions within the final 1 mm of canals. MATERIALS AND METHODS: Fifty roots were divided into five groups that were instrumented apically to the terminus diameter using K-files 15, 20, 30, 40, and 60. ERCLMD measurements were made when the file tip was at major foramen, 0.5 mm and 1.0 mm short of the foramen, when the apex touched to the surface of saline or was immersed 3 mm into saline, and when the canal was dry or was irrigated with saline. The differences between the electronic lengths and the actual lengths were calculated. The data were analyzed using the three-, two-, and one-way ANOVA and the LSD test (p < .05). RESULTS: Overall, the four ERCLMDs demonstrated 12.8% unstable and beyond the foramen measurements (11.3%). About 85% of the beyond the foramen measurements had foramen diameters 0.40 and 0.60. ERCLMD comparisons related to the file positions in the foramen diameters showed significant differences between ERCLMDs in each foramen diameter (p < .05). CONCLUSIONS: All ERCLMDs provided highly accurate measurements within the final 1 mm of the foramen. Wet or dry canals and apex conditions did not adversely affect the accuracy of the ERCLMDs' readings. ProPex II located the file positions in the teeth with different foramen diameters more accurately than the other ERCLMDs.