Method for Radiographic evaluation of the outcome or RCT

Ørstavik and associates suggest the use of the periapical index (PAI) for radiographic evaluation of the outcome of root canal treatment. The PAI relies on the comparison of the radiographs with a set of five radiographic images reported by Brynolf in 1967.17 These images represent a radiographically healthy periapex (score 1) to a large periapical lesion (score 5). Each of the preoperative and recall radiographs is assigned a score according to its resemblance to one of the five reference images. The outcome of root canal treatment using PAI can be classified as "healing" if the lesion size is reduced, "healed" if the lesion has been completely eliminated, or "developing" if a new lesion has formed.