Accuracy of four electronic apex locators: an in vitro evaluation

Abstract— In the present study, the accuracy and operator dependency of four electronic canal length measuring devices (Apex Finder AFA Model 7005, Apex-Finder, Neosono Ultima EZ and Apit 2) were compared under a set of specified conditions. The electronic apex locators were tested in unflared dry, flared wet and flared dry canals, and in a gelatin as well as in a sodium hypochlorite sponge model. Fifteen extracted single-canaled teeth were selected. The differences between canal lengths obtained by the electronic apex locators and actual canal lengths were scored. Only the Apex-Finder was found to be unreliable (measurements higher than ±0.5 mm from the apical foramen). This device was also found to be particularly dependent on operator. A ranking based on a precision of ± 0.1 mm from the apical foramen showed the Apex Finder AFA Model 7005 to be the most accurate. Early coronal flaring did not ensure better or more precise readings. The gelatin model was evaluated to be more suitable for testing electronic apex locators in vitro than the sodium hypochlorite model.     

An in vitro evaluation of the WIRELE-x electronic apex locator

This study evaluated the accuracy of the Wirele-X (Forum Tec, Ashkelon, Israel), a novel Bluetooth-enabled wireless electronic apex locator. Thirty-one extracted teeth with mature apices were used. Under 10X magnification, the actual canal lengths were determined. The teeth were embedded in alginate and electronic canal lengths were obtained using the Root ZX II and Wirele-X electronic apex locators. The actual canal lengths and electronic canal lengths were compared with Student's t-test. The average distance from the file tip to the actual canal length was −0.11 mm (±0.16) for the Root ZX II, and − 0.07 mm (±0.21) for the Wirele-X. There were no statistically significant differences between the two electronic apex locators in their ability to determine the actual canal length (p > 0.05). The wireless apex locator (Wirele-X) and the wired apex locator (Root ZX II) were found to be equally accurate.     

Reliability of different electronic apex locators to detect root perforations in vitro

The aim of this study was to evaluate the accuracy of the electronic apex locator Root ZX compared to the Soho Explorer Mark II Junior and Apit III in detecting root perforations. Extracted human teeth ( n = 30) were perforated artificially in the middle third of the root and embedded in a box containing alginate. Detection of all perforations were carried out with K-files attached to the apex locators tested. The teeth were radiographed after each electronic measurement. The actual location of the tip of the file in relation to the external root surface and the radiographic determination of the perforations were carried out using a stereomicroscope. The mean distance of the tip of the file from the external outline of the root surface was short for all instruments and clinically acceptable (0.06–0.25 mm). There was no clinically significant difference between the morphometric measurements and the radiographic measurements. No statistical significance was found between large perforations (0.55–0.60 mm) and small perforations (0.25–0.40 mm). Under the conditions of this study, all electronic apex locators tested were acceptable clinical tools in the detection of root perforations.     

Comparison of working length determination with radiographs and two electronic apex locators

Aim  To evaluate the accuracy of the Root ZX and Elements-Diagnostic electronic apex locators when compared with radiographs for locating the canal terminus or minor foramen.
Methodology  The canal terminus of 482 canals in 160 maxillary and mandibular teeth was located in vivo with both locators and radiographically. After extraction, the actual location of the minor foramen was determined visually and with magnification. A paired samples t -test, chi-square test and a repeated measure anova at the 0.05 level of significance were used to determine differences between the groups.
Results  The Root ZX located the minor foramen correctly 68% of the time in anterior and premolar teeth, and 58% of the time in molar teeth. The Elements-Diagnostic located the minor foramen correctly 58% of the time in anterior and premolar teeth and 49% of the time in molar teeth. Radiographs located the minor foramen correctly 20% of the time in anterior and premolar teeth and 11% of the time in molar teeth. There was no statistically significant difference between the two locators, but there was a significant difference between them and radiographs. For all teeth, the measurements made by the apex locators were within ±0.5 mm of the minor foramen 100% of the time, whereas for the radiographs, the measurements were within this range only 15% of the time. This difference was significant ( P  = 0.05).
Conclusion  Measuring the location of the minor foramen using the two apex locators was more accurate than radiographs and would reduce the risk of instrumenting and filling beyond the apical foramen.     

Accuracy of the KontrolFlex AccuFile when used with the Root ZX electronic apex locator in vitro

The aims of this study were to determine the efficacy of the KontrolFlex™ Accufile™ compared to the READY•STEEL™ Flexofile® using an electronic apex locator and to evaluate the instrument's design via scanning electron microscopy. Actual canal lengths of 30 extracted teeth were determined under magnification. An alginate model was used to determine experimental canal lengths with the Root ZX II apex locator (EAL) and size #10 Accufiles and Flexofiles. Differences between actual lengths and experimental lengths were compared with Student's t test. The average experimental lengths were short of the actual length by −0.10 mm (±0.34) and −0.12 mm (±0.16) for the Accufile and Flexofile, respectively with no statistical difference (p > 0.05). SEM images revealed similar non-cutting Batt tips and a square cross-section for the Accufile and triangular for the Flexofile. Both files provided similarly high levels of reliability when used with the Root ZX II EAL.     

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

Aim  To compare in vivo the accuracy of two electronic apex locators (EALs) by means of digital radiographic imaging system.
Methodology  Electronic working lengths of 831 canals were determined with the DentaPort ZX and Raypex 5 apex locators and confirmed radiographically. The radiographic images acquired with the aid of a digital radiographic imaging system (VisualiX eHD; Gendex Dental Systems, Des Plaines, IL, USA) were blindly analysed by two independent evaluators. The distance between the file tip and the radiographic apex was measured using dedicated software (VixWin Pro, Gendex Dental Systems, Des Plaines, IL, USA) and the mean distance achieved between different tooth type and EALs were compared statistically. Statistical analyses were performed using the t -test for independent samples and one-way anova with the null hypothesis set as 5%. Positive or negative values were recorded when the file tip was detected beyond or short of the radiographic apex, respectively.
Results  The mean distance between file tip and radiographic apex were −1.08 ± 0.73 and −1.0 ± 0.67 mm considering DentaPort ZX and Raypex 5 groups, respectively, with no significant differences ( P  > 0.05). No statistically significant differences were found amongst the same tooth type when comparing both groups ( P  > 0.05) or amongst different teeth type in the same group ( P  > 0.05).
Conclusions  Within the limitations of this in vivo study, the DentaPort ZX and Raypex 5 were similar in terms of accuracy.     

Accuracy of three electronic apex locators in anterior and posterior teeth: an ex vivo study

Introduction

The aim of this study was to determine in anterior teeth, bicuspids, and molars (1) the accuracy of 3 different electronic apex locators (EALs) in detecting the apical foramen and (2) the accuracy of digital radiography in determining the working length (WL), compared with visible control under a microscope.

Methods

By using radiovideography (RVG), we measured the lengths of 120 root canals with 3 different EALs (Endex, ProPex II, and Root ZX) and compared them with the actual lengths. The accuracy of EALs and RVG was related to each dental category. An endodontic training kit (Pro-Train) was used during experimental procedures.

Results

Statistical analysis showed that the 3 EALs and RVG were less accurate in anterior teeth and molars than in bicuspids. The paired-sample t test showed no statistically significant difference between mesiodistal plane and buccolingual plane digital radiography in all groups.

Conclusions

The 3 EALs tested were more accurate in detecting the apical foramen in bicuspids than in both molars and anterior teeth. Radiographic measurements were not reliable for determining WL in all dental groups in both radiographic planes.     

3种根尖定位仪不同条件下定位根管侧穿孔准确性的体外研究

目的 比较Propex、Raypex(R)5、Root ZX根尖定位仪在不同根管冲洗液中定位根管侧穿孔位置的准确性.方法 选取19颗新鲜拔除的前磨牙,采用ET40超声工作尖破坏根管中下部根管壁,制备根管侧穿孔.使用Propex、Raypex(R)5、Root ZX根尖定位仪定位穿孔位置,比较3种根尖定位仪在不同根管冲洗...     

Ex vivo comparison of two electronic apex locators with different scales and frequencies

AIM: To compare ex vivo the accuracy of two impedance quotient apex locators with different scales and frequencies of the measuring circuit. METHODOLOGY: In each root of 193 extracted human teeth, electronic working length determination (ELD) was carried out with a newly constructed measuring unit. In all cases, ELD was performed using the apex locators Justy II (Hager & Werken, Duisburg, Germany) and Raypex (VDW, Munich, Germany) on the scale points (sp) 0/0.5/1 of each device. A Miller Needle reaching working length was fixed with composite. The corresponding sp and the differences to the other sp were recorded. After histological preparation of the apical region, the teeth were examined under a light microscope. The distances of the Miller Needle tips to the target intervals 'minor foramen-major foramen' and 'apical canal constriction' (apical constriction) were determined for each sp for both devices. The data were statistically analysed by a chi-square test. RESULTS: Precise determination of the target interval 'minor foramen-major foramen' was successful with Raypex 4 in 94.8% (sp 1), 90.7% (sp 0.5) and 72.5% (sp 0) of cases and with Justy II in 59.6% (sp 1), 92.2% (sp 0.5) and 68% (sp 0) of cases. No measurement carried out by Raypex 4 and by Justy II on sp 1 was beyond the major apical foramen. However, on sp 0.5, there were eight measurements for Raypex 4 and four measurements for Justy II beyond the major apical foramen. Overinstrumentation was also recorded for sp 0 in 49 specimens (Raypex 4) and 59 specimens (JustyII). The major apical constriction was met exactly by Raypex 4 in 50.7% (sp 1), 14% (sp 0.5) and 5.2% (sp 0) of cases and by Justy II in 32.1% (sp 1), 23.8% (sp 0.5) and 4.1% (sp 0) of cases. The differences between the determination made with the sp suggested by the manufacturers for Raypex 4 (sp 1) and Justy II (sp 0.5) were not significant (P > 0.05) for the target interval 'minor foramen-major foramen' and significant (P 相似文献   

Comparison of the reliability of "0.5" and "APEX" mark measurements in two frequency-based electronic apex locators

Introduction

A measuring instrument must be both accurate and reliable. This study compared the reliability of the “0.5” and “APEX” mark measurements by using 2 impedance quotient-based electronic apex locators (EALs).

Methods

One hundred four extracted human premolars were used in this study. After access preparation, the teeth were embedded in an alginate model. By using 2 EALs (Root ZX and i-Root), the tooth length was measured at the “0.5” and “APEX” marks with K-files. The file was then cemented, and the apical 3-4 mm was trimmed for the photograph under an operating microscope. The distance between the tip of the file and major foramen (MF) was measured. The intraclass correlation coefficient, the Bland-Altman plot, and box plot were used to compare the reliability.

Results

The intraclass correlation coefficient ranged from 0.976-0.994, indicating excellent agreement in both “0.5” and “APEX” marks. The Bland-Altman plots showed that the limits of agreement (mean ± 2 standard deviations) were small enough to confirm that both marks of the 2 EALs can be used for clinical purposes. The distribution of the measurements and outliers was analyzed by using box plots, and it was found that there was no significant difference between the 2 marks.

Conclusions

There was no significant difference in the reliability of the “0.5” and “APEX” marks for locating the MF in both devices. Accordingly, knowing where each mark indicates is more important for determining the working length than which mark to choose.     

In vitro evaluation of the accuracy of five different electronic apex locators for determining the working length of endodontically retreated teeth

The aim of this study was to evaluate the accuracy of five electronic apex locators (EALs) in determining the working length (WL) of teeth after removal of the root canal obturation materials. A total of 32 extracted straight, single-rooted teeth were used. The actual canal length (AL) was determined and the WL was established by subtracting 0.5 mm from the AL. The root canals were instrumented and divided into two groups. One group (n = 6) served as control, while the other group (n = 26) was the experimental group. In the experimental group, the root canals were obturated using vertically compacted gutta-percha with AH 26 sealer. In both groups, the access cavities were restored with a provisional restoration and stored for 15 days at 37 degrees C and 100% humidity. The root canal obturation material was removed, and the teeth were then mounted in an experimental apparatus. Five EALs were used: Dentaport ZX, ProPex, Foramatron D10, Apex NRG and Apit 7. For the electronic measurement of canal length, a size 25 K-file was used. During measurement, the canal was irrigated with 2.5% sodium hypochlorite. The difference (D) between the AL and the electronically determined length (EDL), AL-EDL, was calculated and recorded for each measurement. Data were analysed by two-way anova and Fisher's PLSD test. In both groups, statistically significant differences were found among the EALs (P < 0.01). In conclusion, the Dentaport ZX, ProPex and Foramatron D10 were more accurate than the other two EALs in determining the WL in teeth after removal of the root canal obturation materials. However, the Apex NRG and Apit 7 were also reliable for determination of the WL in the majority of the cases.     

An evaluation of root ZX and iPex apex locators: an in vivo study

Introduction

iPex is a fourth-generation apex locator (EAL) that has not yet been tested in vivo. The purpose of this study was to compare the accuracy of the Root ZX (J Morita Corp, Tokyo, Japan) and iPex (NSK, Tochigi, Japan) EALs.

Methods

The working length (WL) was determined electronically for 40 root canals of human teeth with a K-file and one of the two EALs. The files were fixed at the WL, and the teeth were extracted. The apical 4 mm of each canal was trimmed to expose the file tip. The samples were observed under a scanning electron microscope, and the distance from the file tip to the point 0.5 mm coronal to the major foramen (the actual WL) was measured. The data were analyzed using the Mann-Whitney U test, and significance was set at P < .05.

Results

No statistically significant differences were found between the Root ZX and iPex devices. The mean distance from the actual WL to the file tip was 0.146 ± 0.43 mm for the Root ZX and 0.128 ± 0.49 mm for the iPex. In determining the actual WL, the Root ZX was accurate 72% of the time to ±0.5 mm and 100% of the time to ±1 mm, whereas the iPex was accurate 57.8% of the time to ±0.5 mm and 100% of the time to ±1 mm.

Conclusions

Under the in vivo clinical conditions of this study, no statistically significant differences were observed between the Root ZX and iPex EALs.     

A comparison between two electronic apex locators: an in vivo investigation

AIM: To compare in vivo the Apex Finder and Root ZX electronic apex locators (EALs) at five different stages during root canal instrumentation. METHODOLOGY: The Apex Finder and Root ZX were used in 64 teeth with either vital or necrotic pulps. Informed consent was obtained by each patient under a study protocol approved by an ethical committee from the University of Trieste. Measurements were made: (stage 1) before instrumentation and irrigation; (stage 2) after brief filing, irrigation with 70% isopropyl alcohol and partial drying; (stage 3) after canal lubrication with EDTA gel (RC-Prep); (stage 4) after complete instrumentation and irrigation with NaOCl 5%; (stage 5) after drying of the final instrumented canal. Stages 2, 3 and 5 were considered low canal conductivity conditions and stage 4 as high. Teeth were then extracted and a size 15 K-file was inserted until its tip was observed under stereomicroscope to reach the foramen and the corresponding length was recorded to an accuracy of 0.25 mm and compared with values derived from the EALs. RESULTS: The data revealed 133 unstable measurements (out of 640): some (68) related to low canal conductivity conditions (more frequently for Root ZX, 67; P < 0.05), and others (63) related to NaOCl presence in the canal (more frequently for Apex Finder, 58; P < 0.05). Accuracy was calculated only on stable measurements. The Root ZX showed significantly (P < 0.05) more precise measurements overall (-0.03 +/- 0.39 mm) compared with the Apex Finder (-0.31 +/- 0.46 mm). Under dry canal conditions the Apex Finder provided the greatest accuracy (-0.0 +/- 0.21) compared with the Root ZX (-0.05 +/- 0.32) (significance P < 0.05). CONCLUSIONS: Under the five different clinical situations both EALs revealed accurate measurements. Apex Finder was negatively influenced by NaOCl in the root canal. The Root ZX was more frequently unable to reveal stable measurements in low conductivity canals.     

Ex vivo evaluation of the ability of the ROOT ZX II to locate the apical foramen and to control the apical extent of rotary canal instrumentation

Aim To evaluate the capacity of the ROOT ZX II to locate the apical foramen and to control the apical extent of rotary instrumentation. Methodology Sixty‐five extracted human single rooted teeth were selected and measured directly using a size 15 K‐Flexofile introduced in the canal until the tip was visible at the major foramen (direct length, DL). The teeth were then measured electronically (EL1) with the ROOT ZX II when used passively, that is without rotation. To test the auto reverse function, the root canals were instrumented with nickel titanium rotary instruments. Instrumentation was carried out apically until rotation was reversed by the automatic apical reverse (AAR) function at different levels (2, 1 and 0.5). The instrumented length at each level was measured and registered as AAR2, AAR1 and AAR0.5, respectively. After instrumentation, a second passive electronic measurement was conducted and noted as electronic length 2 (EL2). All measurements were expressed in millimetres with accuracy set to 0.5 mm. Percentages of acceptable measurements for each electronic reading were calculated and compared using the proportions test. The Wilcoxon’s signed rank test was used to compare the differences between DL/EL1 and DL/EL2, and to compare EL2 with the different AAR measurements. The critical value of statistical significance was 5%. Results EL1 and EL2 measurements were coincident to DL in 56 (86%) and 54 (83%) of the cases, respectively. The proportions test showed no statistically significant difference between these percentages (P > 0.05). The Wilcoxon’s signed rank test did not show any differences (P > 0.05) when comparing the mean difference between DL with EL1 (0.03) and DL with EL2 (0.10). Statistically significant differences were observed when comparing EL2 with AAR2 and with AAR1. Conclusions The ROOT ZX II reliably located the major apical foramen, but was not an accurate method for controlling the apical extent of rotary instrumentation. Rotary instrumentation with the automatic apical reverse feature was always closer to the foramen than expected.     

Accuracy of an electronic apex locator in primary teeth with root resorption

Aim  To evaluate whether root resorption of primary molar teeth affects the accuracy of the Root ZX apex locator and to compare the Root ZX at different meter readings with direct canal measurement.
Methodology  Sixty extracted primary molar teeth with root resorption affecting one sixth to one third of root length were used. The teeth were embedded in an alginate model. A K-type file was used in association with a Root ZX apex locator to measure canal length. Measurements were recorded using the Root ZX meter reading 'Apex' and '0.5 bar'. Actual tooth length was measured with a K-file to the major foramen. All measurements were read under a stereomicroscope at 15× magnification. The deviation of the Root ZX measurement from the actual canal length was determined.
Results  Mean differences between Root ZX length meter reading 'Apex' and actual length were 0.01 ± 0.23 mm whereas mean differences between Root ZX length meter reading '0.5 bar' and actual length were −0.33 ± 0.30 mm. The Root ZX was 96.7% accurate to within ± 0.5 mm of the apical foramen when compared with the actual canal length of primary molars with root resorption.
Conclusions  Using a criterion of ± 0.5 mm, the accuracy of the Root ZX was high and not affected by root resorption. When compared with direct canal measurement, the error in locating the apical foramen was smaller with measurement at meter reading 'Apex' than meter reading '0.5 bar'.     

A comparison between two electronic apex locators: an ex vivo investigation

AIM: To compare ex vivo the performance of the Apex Finder and the Root ZX apex locators, with and without irrigant, in canals having different diameters. METHODOLOGY: Sixty canals in 60 teeth were prepared using stainless steel hand files and 0.04 taper NiTi rotary instruments. During preparation the narrowest diameter of the canal was transported to the apical root surface. The canals were irrigated with RC-Prep and 5% NaOCl solution. Six groups were obtained, each with 10 canals having the same diameter of foramen, either 0.15, 0.20, 0.25, 0.40, 0.60 and 0.80 mm. A size 15 K-file was advanced into each canal until its tip was observed under x10 magnification to reach the foramen and the corresponding length recorded. The measurements were performed to an accuracy of 0.25 mm as a base unit of length. The teeth were then fixed to a plastic bar suspended over a glass container filled with 0.9% NaCl solution. Each apex locator was tested when the K-file was at the foramen, or 0.5, 1.0, 1.5 and 2.0 mm short; with the root apex immersed into the solution; with the canal dry or irrigated with NaCl. To evaluate the accuracy of both electronic apex locators (EALs) each electronically determined distance was compared with the actual length and the data analysed using the General Linear Model and the Student t-test. RESULTS: Out of 2400 measurements 100 were electrically unstable, all with the Root ZX. In total, 521 measurements located the position of the file tip beyond the apex, in general, in high conductive conditions with the Root ZX and in low conductive conditions with the Apex Finder. No significant difference in terms of accuracy was found between the two EALs when the file tip was at the foramen (Root ZX mean +0.12 mm, SD 1.22 mm; Apex Finder mean +0.57 mm, SD 1.16 mm). Comparing all the measurements performed with the file tip within 2 mm of the foramen, in all the different conditions tested, the accuracy was affected (P<0.025) by diameter of the foramen, type of EAL, distance to the apex, and by several interactions. CONCLUSIONS: Under the different ex vivo conditions both EALs provided accurate measurements when the file tip was at the foramen. The accuracy of the Apex Finder was negatively influenced by high conductive conditions, whilst the Root ZX provided inaccurate and unstable measurements mostly in low conductive conditions.