El proposito de este estudio fue comparar la retencion de protesis totales superiores al realizar o no sellado periferico, con el fin de estandarizar una tecnica simplificada que garantice al paciente, que su protesis cumple con los requisitos de estabilidad, retencion y soporte, lo cual se vera reflejado en confort y eficiencia masticatoria para el mismo. La presente Investigacion, de tipo experimental, realizo dobles determinaciones en una muestra de 21 pacientes. Los resultados permiten concluir que no existe diferencia significativa en la retencion, al agregar o no, compuesto de modelar a los bordes de la cubeta Individual. ABSTRACT There is no a work that compare to upper complete denture's retention, by making or not making the border seal. The aim of this work was to begin a researching line that probed the whole conventional technique of complete dentures, in order to standardize a simplified technique that guaranteed the requirements of stability, retention and support of any denture, and in that way giving comfort and masticatory efficiency to the patient. This was a kind of experimental investigation with double measurements in the same patient. The sample consisted of 21 patients. The results indicated that there were not statistically significant differences in retention by adding or not molding compound to the perifery of the custom tray.