RESUMO
The importance of determining working length in root canal therapy is clear for each clinician, and conventional radiography has been the technique of choice so far. But developing computerized technology in radiology and it's show up devices in the market, having several advantages, makes the tendency to use such technology more and more. Despite the many studies in this field, the accuracy of these devices is still unclear. The purpose of this study was to compare the accuracy of conventional radiography and digital radiography in order to estimate the working length of root canal. For this in experimental vitro study 17 root canals of maxillary and mandibular molar teeth on human skulls were selected. Size #15 files were placed in canals in order to assess working length. Then two radiography were taken from each canal: one using conventional and the other one using digital technique, through parallel method of radiation accomplished by special positioning devices. Next the teeth were extracted and real working length was determined. After that two independent observers estimated working length in both conventional and digital radiographs. Finally the mean working lengths of each group were compared with the real amounts using paired t-test analysis. In all tests a significance level of 0.05 was determined. Statistical analysis revealed that digital radiography was more accurate than conventional radiography in determining the working length [P=0.019]. Due to the greater accuracy and other advantages of digital radiography, this method is strongly recommended, regarding the similarities between the study and clinical situation for working length determination