Clinical decision support systems (CDSS) are computer programs developed to give a specialized support to health providers in the clinical decision making process. In Dental Medicine, radiographic images are the primary auxiliary support for a correct diagnosis. ORAD II was developed to evaluate clinical and radiographic characteristics of intra-bone lesions. The aim of this research is to evaluate the reliability of this clinical decision support system in patients observed in a university dental clinic. Two Professors and two students analyzed radiographic images of oral pathologies of nine patients, and its parameters were introduced in the clinical decision support system ORAD II. Within the limitations of our study, we conclude that the software ORADII is useful in assisting the differential diagnosis of oral pathologies, but should always be used only as a complement in the decision-making process.