Ex vivo evaluation of the accuracy of two electronic apex locators during root canal length determination in primary teeth

Aim To evaluate ex vivo the accuracy of two electronic apex locators during root canal length determination in primary incisor and molar teeth with different stages of physiological root resorption. Methodology One calibrated examiner determined the root canal length in 17 primary incisors and 16 primary molars (total of 57 root canals) with different stages of root resorption based on the actual canal length and using two electronic apex locators. Root canal length was measured both visually, with the placement of a K‐file 1 mm short of the apical foramen or the apical resorption bevel, and electronically using two electronic apex locators (Root ZX II – J. Morita Corp. and Mini Apex Locator – SybronEndo) according to the manufacturers’ instructions. Data were analysed statistically using the intraclass correlation (ICC) test. Results Comparison of the actual root canal length and the electronic root canal length measurements revealed high correlation (ICC = 0.99), regardless of the tooth type (single‐rooted and multi‐rooted teeth) or the presence/absence of physiological root resorption. Conclusions Root ZX II and Mini Apex Locator proved useful and accurate for apex foramen location during root canal length measurement in primary incisors and molars.     

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...     

Accuracy of two different apex locators in primary teeth with and without root resorption

The objective of this study was to assess the accuracy of two frequency apex locators, Root ZX (Morita, Kyoto, Japan) and Endex (Osada, Tokyo, Japan) in primary teeth with and without root resorption in vitro. For this study, 90 sound extracted primary teeth (60 molars and 30 incisors; 93 roots with visible resorption and 51 roots without) were selected. A total of 144 root canals were included. After access preparation, root canal lengths were measured visually. The teeth were embedded in an alginate model developed specifically for testing apex locators. Electronic length was determined with two different frequency apex locators, Root ZX (Morita, Kyoto, Japan) and Endex (Osada, Tokyo, Japan). Statistical evaluation was performed using Mann–Whitney U and Wilcoxon W tests (p < 0.05). Results revealed that both apex locator devices did not show similar values to visual length measurements with statistically significant differences in primary teeth with root resorption (p < 0.05). For the teeth without root resorption, Endex showed similar values to visual length measurements with no statistically significant differences (p > 0.05), but Root ZX values were different than visual length and the differences were statistically significant (p < 0.05). There were no significant differences between the two apex locators considering the presence of root resorption. The two frequency apex locators can be recommended for use in root canal therapy for primary teeth with and without root resorption, only if electrical determination of root canal length is supported with other diagnostic measures.     

3种根尖定位仪在口腔急诊应用的临床评价

目的评估口腔急诊需要进行根管治疗的各型急性牙髓炎、急性根尖周炎及牙外伤露髓的患牙,应用3种根尖定位仪测量根管工作长度的准确性。方法对口腔急诊就诊的需要进行根管治疗的284名患者,共317颗患牙随机分为3组,分别采用JustyII、Raypex5和PropexⅡ根尖定位仪进行根管工作长度测量,根据测量值进行根管预备和根管充填,并通过根充后x线根尖片的恰填率进行对比,评价3种根尖定位仪的准确性。结果口腔急诊条件下,3种根尖定位仪准确性有所不同,前牙和前磨牙测量结果3种都较理想;磨牙测量时Raypex5和PropexⅡ更为准确（P〈0．01）。各种急性牙髓炎和急性根尖周炎的比较中,PropexII测量的准确性（分别为94．87％和90．91％）均高于另2种根尖定位仪,受口腔急症患牙干扰因素影响最小。结论PropexⅡ根尖定位仪准确性高,稳定性好,较JustyⅡ和Raypex5更适合在口腔急诊条件下应用。     

Digora及Propex测量根管工作长度准确性的比较研究

目的：评价数字化牙片系统Digora及电子根尖定位仪Propex测量根管工作长度的准确性,为临床应用提供参考依据。方法???选取临床中需拔牙的90例患者260颗患牙（369个牙根）为研究对象,首先对患牙拍摄数字化牙片,利用Digora系统中的长度工具测量牙片上牙齿根管长度,然后对患牙开髓,电子根尖定位仪Propex测量根管工作长度,最后拔除患牙直视下测量根管实际长度并以此长度为标准,计算Digora牙片测量法、Propex电测法与实际根管长度的差值,分别以1、1.5?mm误差评定两法测量根管工作长度的准确性。结果???牙片法测量值与拔牙实测值差值为（2.163±1.194）mm,电测法测量值与拔牙实测值差值为（0.214±0.542）mm。以1?mm内为可接受范围,牙片法准确率为21.68%,电测法为91.87%;若以1.5?mm以内为可接受范围,则两法准确率分别为30.35%、95.66%。牙片法准确率均明显低于电测法（P<0.01）。结论??采用Digora系统长度工具直接测量牙片上根管长度时,误差较大,不能直接指导临床操作。Propex能较准确地测量根管工作长度。     

根尖狭窄破坏对Propex Ⅱ电子根尖定位仪准确性的影响

目的:研究在根尖狭窄破坏的情况下,PropexⅡ测量准确性与根尖孔大小的相关性.方法:磨除40颗单直根管离体牙根尖l mm,采用2％液态琼脂凝胶注入卡斯特罗模型,使用PropexⅡ电子根尖定位仪进行根管长度测量,记录测量值(LP),计算实际测量的根管工作长度(L)与电测法测量的根管工作长度(LP)的差值(△L).显微镜下拍摄根尖孔图像,利用Photoshop CS 6.0软件测量根尖孔面积(S).采用SPSS 22.0软件包对测量结果进行直线相关回归分析.结果:以±0.5 mm作为△L的允许范围,△L均为正值.在根尖狭窄破坏的情况下,PropexⅡ的测量准确率为52.5％.R值为0.903,S与△L呈线性相关.建立的线性回归方程为:S=0.04+0.11×△L.结论:在根尖狭窄破坏的情况下,电子根尖定位仪准确性下降;根尖孔面积越大,准确性越差.     

Accuracy of electronic apex locators using heat-treated Ni-Ti file

This study investigated the accuracy of two electronic apex locators (DentaPort and Bingo) using heat-treated nickel-titanium files. The true root canal length of 30 single-rooted teeth was determined using K files. Next, the electronically measured length was determined using two nickel-titanium files (ProGlider and HyFlex EDM Glide Path File) with two electronic apex locators at the ‘APEX’ marks. The accuracy of the electronic apex locator was evaluated by comparing the true root canal length and electronically measured length for each measurement. There was no significant difference between the measurements with two nickel-titanium files, and all differences between true root canal length and electronically measured length were within ±0.5 mm regardless of the type of nickel-titanium files or electronic apex locators. Based on the results, the heat treatment of the nickel-titanium files showed no adverse effects on the working length determination using electronic apex locators.     

Determining the apical terminus of root-end resected teeth using three modern apex locators: a comparative ex vivo study

AIM: To assess ex vivo the accuracy of various electronic apex locators in locating the apical terminus of root-end resected teeth. METHODOLOGY: Ninety extracted human posterior teeth (182 root canals) were prepared to a minimum size of 40 and filled with gutta-percha and sealer. After resection of the apical 3 mm of the root, the root canal filling was removed using HERO rotary instruments. The size of the root canal at the apical terminus after removal of the filling ranged from size 50 to 90. The root canal length to the apical terminus was determined using 3 apex locators (Root ZX, Raypex4 and Apex Pointer). A new mounting model that utilized a micrometer was used to perform the measurements and to visually determine the actual position of the apical terminus. The frequency of locating the apical terminus and the corresponding 95% confidence interval (CI) were calculated. Additionally, the coefficient of repeatability of each apex locator and the limits of inter-operator agreement were determined. RESULTS: All apex locators showed an acceptable repeatability (0.02-0.03 mm coefficient of repeatability) and narrow limits of inter-operator agreement (+0.07 and -0.07 mm). The accuracy of determining the apical terminus within 1 mm in the root canal was as follows: Root ZX 90% (164/182 root-canals) [95%CI: 86-94%], Raypex4 74% (135/182 root-canals) [95%CI: 68-80%], and Apex Pointer 71% (129/182 root canals) [95%CI: 65-77%]. No over-instrumentation resulted when the Root ZX device was used. In contrast, using the Raypex4 or the Apex Pointer device resulted in over-instrumentation in 8 of 182 root canals (4%). CONCLUSIONS: Under the conditions of this study all three apex locators were able to detect the apical terminus of root-end resected teeth with an acceptable range. The Root ZX device was the most accurate without over-instrumentation of the root canals.     

Accuracy of different electronic apex locators in determination of minimum Root perforation diameter

This study aims to evaluate the ability of Raypex 6, Propex Pixi, Dentaport ZX, Apex ID, Propex II and Dr.'s Finder NEO to detect minimum root canal perforation diameter. One hundred single-rooted, extracted human teeth were artificially perforated by 5 burs in different diameters (0.25–1.25 mm) in 5 mm above the apex. Twenty teeth were assigned to each group. The actual canal lengths (AL) were measured under stereomicroscope followed by a measurement of electronic canal length (EL) using each electronic apex locator (EAL). None of the EALs were able to detect the perforation at diameters of 0.50 and 0.25 mm. Although all EALs used in our study were unable to detect perforations at diameters of 0.5 mm and 0.25 mm, they were highly successful in the determination of simulated root perforations at diameters of 1.25, 1 and 0.75 mm.     

Electronic determination of root canal length in primary teeth with and without root resorption

AIM: To test an electrical device for determining root canal length in primary teeth in vitro, and to compare it with the radiographic length measurement. METHODOLOGY: Two examiners determined the root canal length of 24 extracted maxillary primary incisors (12 with visible root resorption and 12 without) using an electrical root canal meter (Tri Auto ZX, Morita, Dietzenbach, Germany). The instrument was left in the root canal after the second examination and a radiograph was taken. The whole tooth was cleared by immersion in methylsalicylate and subsequently photographed. Both radiographs and photographs of cleared teeth were measured and compared with the electronic measurements. RESULTS: The evaluation of the radiographs showed a mean distance between the instrument tips and apices of 0.60 (+/- 0.41) mm; evaluation of the cleared teeth showed an equivalent distance of 0.62 (+/- 0.40) mm. The mean distance between instrument tip and acceptable working length (determined with the clearing method) was 0.26 (+/- 0.24) mm in teeth without resorption and 0.29 (+/- 0.30) mm in teeth with resorption. CONCLUSION: The presence of resorption in primary teeth did not affect the accuracy of electrical measurement of root canal length in vitro. The application of this method in primary teeth should be evaluated further.     

Accuracy of two electronic apex locators in primary teeth with and without apical resorption: a laboratory study

Aim To evaluate the accuracy of the Root ZX (J Morita Corp., Kyoto, Japan) and Tri Auto ZX (J Morita Corp.) devices for measuring root canal length in primary teeth with and without apical resorption. Methodology Thirty‐four extracted human primary molar teeth with resorption and 19 primary teeth without resorption were collected. After endodontic access preparation, the actual lengths of the teeth were determined. The teeth were then embedded in an alginate model to determine the electronic working length measurement. Statistical evaluation was completed using Student’s t‐tests. Results For the Root ZX, there was no significant difference between those teeth with root resorption and those without. However, for the Tri Auto ZX, there was a significant difference in the electronic measurements between those teeth with root resorption and those without (P < 0.05). Significant differences were found amongst the measurements of the two apex locators (P < 0.05). For root canals with resorption, the respective accuracy rates (within ±0.5 mm) of Root ZX and Tri Auto ZX were 83.33% and 89.47%; within ±1 mm, the Root ZX and Tri Auto ZX demonstrated 98.95% and 100% accuracy, respectively. For root canals with no resorption, the percentage of measurements within ±0.5 mm of the apical construction was 89.28% for the Root ZX and 80.35% for the Tri Auto ZX. The accuracy within ±1 mm of the Root ZX and the Tri Auto ZX was 98.22% and 100%, respectively. Conclusion Within the limitations of this laboratory study, the presence of resorption affected the performance of the Tri Auto ZX more than the Root ZX.     

Accuracy of a new apex locator: an in vitro study

AIM: The purpose of this study was to test in an in vitro model the accuracy of a Bingo 1020 electronic apex locator, to compare the results to those of a well known apex locator, Root ZX, as well as to those of the radiographic method of tooth length determination. METHODOLOGY: A total of 120 extracted teeth, preserved in Thymol solution and kept refrigerated, was used for the study. The experiment was performed on single-rooted teeth and on one-root canal, chosen randomly, in multirooted teeth. The teeth were randomly divided into 12 groups of 10 teeth each. After access preparation, the actual length (AL) was measured. The teeth were embedded in an alginate model specially developed for testing apex locators. Electronic tooth length measurements (EL) were carried out prior to root canal preparation using the two electronic apex locators (EAL) - Root ZX and Bingo 1020; three measurements were taken and an average computed. After the third measurement, the file was left in the root canal and a periapical radiograph was taken. The radiographic length (RL) was recorded by measuring the file length from the coronal reference point to the tip of the file. Each root canal was then prepared to a no. 40 K-file diameter using a standardized technique; saline was used for irrigation. Upon completion of the root canal preparation, EL measurements were taken by each EAL in dry conditions and with different irrigation solutions. Each measurement was repeated three times. The RL was recorded according to the last EL measurement. Results were subjected to statistical analysis. RESULTS: In all parameters tested, a significant statistical difference was found between Bingo 1020 and the Root ZX. Measurements obtained using the Bingo 1020 were consistently closer to the AL (0.08 mm) than those obtained using the Root ZX. Both EALs measured the tooth length with great accuracy and a positive correlation of 0.76 (P = 0.00) existed between the two devices. No significant difference was found between the two apex locators when measurements were taken with the different irrigants (P = 0.34) and the content of the root canal did not affect the accuracy of the measurements. Lengths obtained by calculations from the radiographs were longer than the AL as well as the length obtained by both EALs (P = 0.00). CONCLUSIONS: The Bingo 1020 proved to be as reliable as Root ZX and was user friendly. Under the experimental conditions, electronic measurements were more reliable than radiographs in the process of root length determination.     

Determination of working length for teeth with wide or immature apices: a review

Practitioners face several challenges during the root canal treatment of teeth with wide or immature apices, one of which is working length determination. There is relatively little data regarding the value of radiography and electronic apex locator (EAL) use when root formation is incomplete, and supplementary measurement techniques may be helpful. This review considers length determination for canals with wide or completely open apices in permanent and primary teeth. The Ovid Medline, Web of Science and Scopus databases were searched individually and in combinations to August 2012 using the subject headings ‘working length determination’ and ‘open apex’ and revealed only one article. Further headings, ‘tooth apex’, ‘apical constriction’, ‘resorption’, ‘foramen size’, ‘mature root apex’, ‘immature root apex’, ‘working length determination’, ‘apexification’, ‘open apices’, ‘open apex’, ‘open apical foramina’, ‘canal length determination’, ‘immature teeth’, ‘apical diameters’, ‘electronic apex locators’, ‘primary teeth’, ‘treatment outcome’ and ‘clinical outcome’ were entered. Potentially useful articles were chosen for a manual search of bibliography as well as a forward search of citations. Other investigations revealed case reports and some research related to open apices and laboratory studies evaluating EALs, radiography and tactile methods. Some involved permanent teeth of various apical diameters and primary teeth with and without resorption. There is a need to define the term ‘open apex’. Clinicians should be aware of the benefits and limitations of all canal measuring techniques involved in managing this problem.     

Direct comparison of working length determination by ProPex electronic apex locator and radiographic method--an in vitro study

The purpose of this study was to compare the accuracy of electronic and radiographical working length determination in extracted molars. Palatal root canals of twenty maxillary molars were used. Teeth were randomly divided into two groups. In case of the first group the working length was measured by apex locator (Propex, Dentsply-Maillefer), and in the second group it was measured with radiographic method (RVG, Trophy). The files, used for measuring the working length, were cemented into the teeth. The apical half of the root was ground, and the tips of the files visualised as well as the apical region of the root canal with the apical constriction. Standard digital photographs were taken from the prepared samples, and the distance between the tip of the file and the physiological foramen was measured. Two sample t test was used for statistical analysis. The physiological foramen was approached on average to 0.11 mm by the electronic method and to 0.58 mm by the radiological method. There was no significant difference in the measuring accuracy between the two methods (p=0.10). The electronic and radiological working length determination may prove to show an equivalent consistency.     

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.     

根尖定位仪ProPexⅡ测量乳牙工作长度准确性的临床研究

目的：评估根尖定位仪ProPexⅡ测量乳牙工作长度的准确性。方法：本研究选择需拔牙的患儿32名,总共37颗乳牙,共计48个根管,其中牙根完整者22个,牙根发生不同程度吸收者26个,在口内用定位仪ProPexⅡ测量工作长度（EL）,然后拔除患牙,体外在显微镜下用游标卡尺及15号K锉测量每个根管的实际长度（AL）,两值均测量3次,取平均值,并将EL与AL相比较,采用SPSS13.0统计数据。结果：对于无根吸收的根管,PropexⅡ在AL±0.5mm范围内的准确率为77.27%,在AL±1mm范围内的准确率为95.45%,伴有根吸收者则分别为61.54%及88.46%,若不考虑牙根有无吸收EL和AL无统计学差异（P=0.359）。结论：ProPexⅡ根尖定位仪测定乳牙工作长度准确率较高,不论乳牙有无根吸收均建议使用定位仪ProPexⅡ确定工作长度,以提高根管充填质量,延长乳牙行使功能的时间。     

Anatomical challenges,electronic working length determination and current developments in root canal preparation of primary molar teeth

Paediatric endodontics is an integral part of dental practice that aims to preserve fully functional primary teeth in the dental arch. Pulpectomy of primary molars presents a unique challenge for dental practitioners. Negotiation and thorough instrumentation of bizarre and tortuous canals encased in roots programmed for physiological resorption are the main challenges for this treatment approach. Consequently, numerous in vitro and in vivo studies have been conducted to validate the application of some contemporary endodontic armamentarium for effective treatment in primary molars whilst maintaining favourable clinical outcomes. Electronic apex locators, rotary nickel–titanium files and irrigation techniques are at the forefront of endodontic armamentarium in paediatric dentistry. Hence, this review aims to map out the root and root canal morphology of primary molars, to discuss the application of electronic apex locators in primary molars and to provide an update on the preparation of their root canal systems.     

Clinical evaluation of the measuring accuracy of ROOT ZX in primary teeth

OBJECTIVE: The aim of this study was to assess the accuracy of an electronic device (Root ZX; Morita, Tokyo, Japan) for measuring the root canal length in primary teeth. STUDY DESIGN: The pulp tissue was removed from 71 nonrestorable teeth scheduled to be extracted under general anesthesia, and the root canals (n = 105) were irrigated (H(2)O(2), 3%; NaOCl, 1%). Subsequently, the length was determined clinically with the electronic device prior to extraction. Treatments were performed by 2 dentists (42 and 63 root canals). After extraction, the real length was recorded and the 2 measurements were compared. RESULTS: Measurements were affected significantly by the dentists (P < .01; chi(2)). However, regression analysis revealed sufficient accuracy of the device, with a tendency to estimate the root canal length just short (x = -0.98 +/- 1.75 mm) of the apex. These results were not influenced by tooth type, root canal type, status of the periapex, or clinical condition (P > .05; chi(2)). CONCLUSION: Root ZX can be strongly recommended for clinical implementation of endodontics in primary teeth, particularly when treating fidgety children.     

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

The purpose of this study was to compare the accuracy of a two-frequency (Root ZX) and a five-frequency (Endo Analyzer Model 8005) electronic apex locator under clinical conditions. Thirty-two teeth planned for extraction were used. The coronal portion of each canal was flared using Gates Glidden drills and Orifice Shapers. The canals were irrigated with 2.6% sodium hypochlorite. A K-type file was used to determine a separate working length in each canal using the electronic apex locators. The teeth were extracted and the apical 4 mm of each root canal was exposed along the long axis of the tooth. Photographic slides of each canal were projected and the file position in relation to the minor diameter was determined by two investigators. The mean distance between the electronic apex locator working length and minor diameter was 1.03 mm for the Endo Analyzer and 0.19 mm for the Root ZX. A paired sample t test showed that the Endo Analyzer had significantly longer readings beyond the minor diameter than the Root ZX (p < 0.0001). The ability to locate the minor diameter (+/- 0.5 mm) was 90.7% for the Root ZX and 34.4% for the Endo Analyzer Model 8005.     

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.