Assessing the Efficacy of a Lightening Solution of Radiographic Film in Root Length Determination

Working length determination is one of the most important steps in the root canal therapy. Radiographs with suitable brightness are essential for the accurate working length determination. Therefore, the aim of this study was to assess the efficacy of a lightening solution of radiographic film in root length determination. In this laboratory study, out of 18 maxillary molars of four dry human skulls, 29 canals were selected. After access preparation, the root canals were coronally flared. A 25-size file was placed in the full working length and radiography of each canal was performed one time with the normal exposure time and two times with the increased exposure time. Then endodontic file was placed 2mm shorter and radiographs were obtained with the normal and increased exposure time like the former. After processing, one series of overexposed radiographs with full length and short length were corrected with the lightening solution. An observer evaluated all radiographs and the study data were analyzed by SPSS16 using kappa test. Significant differences were found between lightened radiographs and standard radiographs for the full length group, though no significant differences were observed between lightened and overexposed radiographs. Moreover, significant differences were found between lightened radiographs and overexposed radiographs for the short length group, though not between lightened and standard radiographs. Under the limitations of this study, lightening solution improved only the diagnostic quality of darkened radiographs for the short length ones.