Comparison of Accuracy of Conventional (F, E-speed) and Digital Radiographies (CMOS) for Working Length Estimation

Determination of the correct working length is one of the main factors that lead to success in root canal therapy. This laboratory study aimed to compare the accuracy of conventional (F, E-speed) radiography and Complementary Metal Oxide Semiconductor (CMOS) digital radiography in working length measurement.
In this laboratory study, access cavities were prepared in 40 extracted maxillary central incisors with straight and single canals. Size 15 K-file was introduced into the each canal until it was appeared through the apical foramen. The file was then removed and measured by a digital caliper with precision of 0.01 mm. Actual working length was considered 1 mm less than the measurement showed by the caliper (Gold standard). At the next stage, each tooth together with its related K-file was positioned in a dried skull and then, periapical conventional and digital radiographies were taken with parallel technique. All the radiographs were measured by two radiologists. Statistical analysis was performed using repeated measures ANOVA and paired t-test.
No statistically significant difference was observed between conventional and digital radiographies regarding working length measurement (P>0.05). Conventional and digital radiographies demonstrated significantly higher scores of working length measurement compared to the Gold standard (P Although CMOS had no significant superiority over conventional radiography, if both techniques are available, using CMOS is recommended due to significant reduction of radiation dose.
Keywords: Working length, Conventional radiography