SummaryRadiovisiography is a digital intraoral radiographic imaging system requiring a substantial reduction of radiation dosage to the patient over film. For Radiovisiography to replace film, it must be shown to be as efficacious. In this study, a technique of obtaining Radiovisiography and D‐speed film images from the same X‐ ray beam was developed with the use of rare‐earth filters. The quality of the resultant radiovisiographic images was verifiedin vitrowith pure radiovisiographic images of teeth in a dried mandible with soft tissue simulation. Two examiners compared Radiovisiography with D‐speed film for 20 root length estimations using the samein‐vitromodel. A clinical study was then carried out on mandibular molars of patients undergoing endodontic treatment, where 35 root lengths were obtained. The results of bothin vitroand clinical studies showed no statistical differences in the estimated root lengths using the two imaging systems. The measuring grid available in the Radiovisiography unit produced similarly accurate results. Furthermore, the clinical study demonstrated the effective use of Radiovisiography during root canal treatment, with insta