An in vivo radiographic evaluation of the accuracy of Apex and iPex electronic Apex locators

The aim of this study was to evaluate in vivo the clinical applicability of two electronic apex locators (EALs) - Apex (Septodont) and iPex (NSK) - in different groups of human teeth by using radiography. The working lengths (WLs) of 100 root canals were determined electronically. The EAL to be used first was chosen randomly and a K-file was inserted into the root canal until the EAL display indicated the location of the apical constriction (0 mm). The K-file was fixed to the tooth and a periapical radiograph was taken using a radiographic film holder. The K-file was removed and the WL was measured. The same procedure was repeated using the other EAL. Radiographs were examined with the aid of a light-box with lens of ×4 magnification by two blinded experienced endodontists. The distance between the file tip and the root apex was recorded as follows: (A) +1 to 0 mm, (B) -0.1 to 0.5 mm, (C) -0.6 to 1 mm, (D) -1.1 to 1.5 mm, and (E) -1.6 mm or greater. For statistical purposes, these scores were divided into 2 subgroups according to the radiographic apex: acceptable (B, C, and D) and non-acceptable (A and E). Statistically significant differences were not found between the results of Apex and iPex in terms of acceptable and non-acceptable measurements (p>0.05) or in terms of the distance recorded from file tip and the radiographic apex (p>0.05). Apex and iPex EALs provided reliable measurements for WL determination for endodontic therapy.

Influence of pulp condition on the accuracy of an electronic foramen locator in posterior teeth: an in vivo study

The aim of this study was to assess, in vivo, the accuracy of the NovApex (R) electronic foramen locator in determining working length (WL) in vital and necrotic posterior teeth. The NovApex (R) was used in 144 canals: 35 teeth with vital pulps (68 canals) and 42 teeth with necrotic pulps (76 canals). WL was measured with the NovApex (R) locator and confirmed using the radiographic method. Differences between electronic and radiographic measurements ranging between 0.0 and 0.4 millimeters were classified as acceptable; differences equal to or greater than 0.5 millimeter were considered unacceptable. Pearson's chi-square test was used to assess the influence of pulp condition on the accuracy of NovApex (R) (alpha = 0.05). Regardless of pulp condition, differences between electronic and radiographic WL measurements were acceptable in 73.61% of the canals. No statistically significant differences in accuracy were observed when comparing vital and necrotic canals (p > 0.05). There were 38 unacceptable measurements. In none of these cases was the file tip located beyond the radiographic apex; in 32, it was located short of the NovApex (R) measurement. Pulp condition had no significant effect on the accuracy of NovApex (R).

Effect of pre-flaring and file size on the accuracy of two electronic apex locators

Objective: This ex vivo study evaluated the effect of pre-flaring and file size on the accuracy of the Root ZX and Novapex electronic apex locators (EALs). Material and methods: The actual working length (WL) was set 1 mm short of the apical foramen in the palatal root canals of 24 extracted maxillary molars. The teeth were embedded in an alginate mold, and two examiners performed the electronic measurements using #10, #15, and #20 K-files. The files were inserted into the root canals until the "0.0" or "APEX" signals were observed on the LED or display screens for the Novapex and Root ZX, respectively, retracting to the 1.0 mark. The measurements were repeated after the pre-flaring using the S1 and SX Pro-Taper instruments. Two measurements were performed for each condition and the means were used. Intra-class correlation coefficients (ICCs) were calculated to verify the intra-and inter-examiner agreement. The mean differences between the WL and electronic length values were analyzed by the three-way ANOVA test (p<0.05). Results: ICCs were high (>0.8) and the results demonstrated a similar accuracy for both EALs (p>0.05). Statistically significant accurate measurements were verified in the pre-flared canals, except for the Novapex using a #20 K-file. Conclusions: The tested EALs showed acceptable accuracy, whereas the pre-flaring procedure revealed a more significant effect than the used file size.

In vivo accuracy of conventional and digital radiographic methods in confirming root canal working length determination by Root ZX

Objectives: To compare, in vivo, the accuracy of conventional and digital radiographic methods in determining root canal working length. Material and Methods: Twenty-five maxillary incisor or canine teeth from 22 patients were used in this study. Considering the preoperative radiographs as the baseline, a 25 K file was inserted into the root canal to the point where the Root ZX electronic apex locator indicated the APEX measurement in the screen. From this measurement, 1 mm was subtracted for positioning the file. The radiographic measurements were made using a digital sensor (Digora 1.51) or conventional type-E films, size 2, following the paralleling technique, to determine the distance of the file tip and the radiographic apex. Results: The Student "t" test indicated mean distances of 1.11 mm to conventional and 1.20 mm for the digital method and indicated a significant statistical difference (p<0.05). Conclusions: The conventional radiographic method was found to be superior to the digital one in determining the working length of the root canal.

Accuracy of five electronic foramen locators with different operating systems: na 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.