Introduccion y objetivo:La radiografia es el principal medio usado por el endodoncista para verificar las caracteristicas delsistema de conductos, el problema es su caracter bidimensional, que puede esconder informacionimportante para garantizar el exito del tratamiento, lo que hace necesario evaluar medios de contrastecoadyuvantes que aumenten la sensibilidad del instrumento. Determinar validez y confiabilidad de dostecnicas de identificacion de conductos laterales.Materiales y metodos:Estudio de prueba diagnostica en 82 premolares inferiores de humanos recien extraidos, con formacionradicular completa. Las mediciones se realizaron en radiografias periapicales de dientes con y sin mediode contraste, usando tres dimensiones (orto-mesio y disto-radial). Para el analisis se utilizaron pruebasde sensibilidad y especificidad con un nivel de significancia del 5%. La confiabilidad de la prueba para eltipo de conducto se evaluo con el Kappa Cohen.Resultados:La tecnica radiografica con medio de contraste con orientacion distal fue la mas sensible (p=0,000).Mientras que la tecnica radiografica sin medio de contraste con orientacion mesial fue la mas especifica(p=0,000). No se encontro concordancia entre las dos tecnicas para la identificacion de conductos.Conclusion:La tecnica radiografica con medio de contraste presento baja sensibilidad para identificar las variantesanatomicas en el conducto radicular, excepto en los conductos tipo delta, donde los resultados sesobreestimaron. No hubo concordancia entre las dos tecnicas para identificar el tipo de conducto, lo quesugiere no ser confiable al momento de utilizarla para tratamientos de conductos. Abstract Introduction and objective:Radiograph is the head tool used for the endodontist to verify the characteristics of the root canalsystem; the problem is its two-dimensional character that could hide important information to ensurethe success of the treatment, for that reason, it is necessary to evaluate the coadjutant contrast methodsthat increase the sensitivity of the instrument. To determine validity and reliability of two identifyingtechniques of radicular lateral ducts.Materials and methods:A diagnostic study was carried out in 82 recently extracted human lower premolars, with completeradicular formation. The measures were carried out by means of periapical radiographs with and withoutcontrast media, using three dimensions (ortho-radial, medialradial and distoradial). For the analysis,tests of sensitivity and specificity were used with a level of significance of 5%. Reliability of the test forthe type of radicular duct was evaluated by means of Kappa Cohen.Results:Radiographic technique with the contrast media and with distal orientation was the most sensitive(p=0,000). While the radiographic technique without contrast media and with mesial orientation was themost specific (p=0,000). No concordance was found between both techniques for the identification ofradicular ducts.Conclusions:Radiographic technique with contrast media showed a low sensitivity to identify anatomic variants inthe radicular duct, except in delta type ducts, where the results were overestimated. There was noconcordance between both techniques to identify the type of duct what suggests not to be reliable at themoment of being used to endodontic treatment.