In-vitro Comparison of Three Imaging Techniques for Root-Canal Measurements

Methods: Twenty extracted permanent teeth with complete root formation were used. Hedström files (08,10,15) were inserted into the canal until the tip of the file was just seen at the apical foramen. The files were fixed by filling the access with composite resin. The teeth with files in the canals were radiographed with three imaging systems (RadioVisioGraphy, storage phosphor digital imaging and conventional radiography) at 0° projections. All films and sensors were exposed by paralleling technique. The obtained images were evaluated with/without magnification, using computer software for the digital images and a viewbox for conventional radiographs by two blinded examiners. The “revealer” mode of the software was also evaluated for RVG images. The accuracy of three systems to determine the root-canal length was evaluated by measuring the distance from the tip of the file to the radiographic apex. The percentage of concordance between two examiners was calculated using Cohen's kappa and the data was analyzed using non-parametric tests.

Results: Most of the values corresponding with the apex occurred with conventional radiography while the use of magnification (x6) did not make any statistically significant contribution to the results (p<0,05). The two digital systems gave more negative results which improved with size15 file.

Conclusion: The conventional radiography is still the technique of choice when determining the root-canal lengths, although digital systems gave comparable results with size 10 and 15 files.