An Ex Vivo Comparison of Electronic Apex Locator Teaching Models

Introduction: This study aimed to develop a simple and inexpensive ex vivo model to teach students the use of electronic apex locators in a preclinical setting. Methods: Using 27 extracted human teeth, the Raypex 5 (VDW, Munich, Germany) and Dentaport ZX (J. Morita Co, Kyoto, Japan) were tested in three different media (ie, alginate, sugar-free gelatin, and 0.9% sodium chloride solution). Working lengths determined by these models were compared with those obtained by digital radiography and direct visualization using a linear mixed modeling statistical approach. Results: Raypex 5 exhibited a higher percentage of measurements accurate to +/- 0.5 mm and +/- 1.0 mm of the control across all three media in all tooth types. In multirooted teeth, alginate showed the highest accuracy. Conclusions: The most accurate EAL/embedding medium combination was Raypex 5/alginate to both +/- 0.5 mm and +/- 1.0 mm of the control. The model tested in this study was accurate, easy to assemble, and cost-effective, making it suitable for teaching purposes. (J Endod 2011;37:1147-1151)