Accuracy of Root ZX in teeth with simulated root perforation in the presence of gel or liquid type endodontic irrigant

OBJECTIVES: To evaluate the accuracy of the Root ZX in teeth with simulated root perforation in the presence of gel or liquid type endodontic irrigants, such as saline, 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine liquid, 2% chlorhexidine gel, and RC-Prep, and also to determine the electrical conductivities of these endodontic irrigants. MATERIALS AND METHODS: A root perforation was simulated on twenty freshly extracted teeth by means of a small perforation made on the proximal surface of the root at 4 mm from the anatomic apex. Root ZX was used to locate root perforation and measure the electronic working lengths. The results obtained were compared with the actual working length (AWL) and the actual location of perforations (AP), allowing tolerances of 0.5 or 1.0 mm. Measurements within these limits were considered as acceptable. Chi-square test or the Fisher's exact test was used to evaluate significance. Electrical conductivities of each irrigant were also measured with an electrical conductivity tester. RESULTS: The accuracies of the Root ZX in perforated teeth were significantly different between liquid types (saline, NaOCl) and gel types (chlorhexidine gel, RC-Prep). The accuracies of electronic working lengths in perforated teeth were higher in gel types than in liquid types. The accuracy in locating root perforation was higher in liquid types than gel types. 5.25% NaOCl had the highest electrical conductivity, whereas 2% chlorhexidine gel and RC-Prep gel had the lowest electrical conductivities among the five irrigants. CONCLUSIONS: Different canal irrigants with different electrical conductivities may affect the accuracy of the Root ZX in perforated teeth.

The Evaluation of Immunochromatographic Assay kit for Rapid Detection of Hepatitis B Surface Antigen

We evaluated Immunochromatographic assay kit to screen HBsAg in human serum. When the reference HBsAg was applyed to ICA, HA and EIA kits, the limit of detection for HBsAg were found out to be 4, 2 and 0.25 ng/ml respectively. But ICA kit required 5 minutes to read the result whereas HA and EIA kit more than one hour. The sensitivity was 97% (29 of 30 samples) and the specificity 100% (45 samples) compared with conventional EIA. The ICA kit needs no instrument or machine to perform the test contrary to the conventional methods. Therefore, this rapid and sensitive ICA kit can be used for HBsAg-screening, especially in the emergency room and in the scene of the accident.