Clinical Accuracy and Precision of 3 Multifrequency Electronic Apex Locators Assessed through Micro-Computed Tomographic 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 (Dentsply Maillefer, Ballaigues, Switzerland), Woodpex III (Woodpecker Medical Instrument Co, Guilin, China), and Root ZX II (J Morita, Tokyo, Japan). 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. Data sets were coregistered, 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 the tested EALs (P > .05). Propex Pixi was significantly less precise than Root ZX II (P < .05), whereas no difference was found between Woodpex III and 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 major foramen than Propex Pixi.

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-computed tomography (micro-CT) as the analytical tool. METHODS: Eleven vital teeth planned for extraction from 5 patients 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 of 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 χ2 test was applied to compare the ability of the EALs to detect the position of the major foramen, and the t test for dependent variables was used to verify differences in the 2 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 = .82) or in their ability to detect the position of the major foramen (χ2 = 0.2588; P = .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.

Effect of Photodynamic Therapy on Postoperative Pain in Posterior Teeth with Symptomatic Apical Periodontitis.

This study aimed to evaluate the impact of photodynamic therapy (PDT) after root canal preparation on pain relief in posterior teeth presenting with symptomatic apical periodontitis (SAP). A visual analog scale (VAS) was completed by the patients which registered their pain perception as none (0), mild (1-3), moderate (4-7), or severe (8-10). Only patients who registered moderate or severe pain were included. Seventy patients were allocated to two groups (n=35): a control group (CG) without the PDT application and an intervention group with PDT application (PG). The same chemo-mechanical preparation was achieved in both groups. In the PG, 150 µM methylene blue (MB)Please remove the underline was placed inside the canal for 2 minutes and a 660 nm wavelength laser was applied through a fiber for 3 minutes (100 mW, 600 J/cm², total 18J). The patients were asked to register their pain perception in the VAS document after 24-h, 72-h, and 1-week intervals. The number of tablets taken for pain relief was also recorded. The Mann-Whitney, Students T-test and Fisher´s exact tests were used for statistical analysis (P < .05). After 1 week, 32 patients in the CG and 33 in the PG returned their VAS cards. The PG resulted in lower pain levels after the 24-hour interval (median 0) than the CG (median 2); there was no difference between both groups at 72-h and 1-week intervals. The decrease in pain was higher in the PG at all time-intervals when compared to the CG. There was no difference in the mean number of tablets taken for pain relief (P > .05). Within the limitations of this study, it can be concluded that PDT was efficient in decreasing pain in teeth presenting with SAP. There was no difference observed after 72 hours and there was no impact on the intake of pain relief medication.