Digital Radiograph Registration and Subtraction: A Useful Tool for the Evaluation of the Progress of Chronic Apical Periodontitis

Abstract

The purpose of this study was to evaluate the suitability of a digital radiograph registration and subtraction software for a sensitive and reliable assessment of the progress of chronic apical periodontitis. Ninety cases of teeth with chronic apical periodontitis have been studied. In each case, a preoperative radiograph was taken, root canals were prepared, and a Ca(OH)2 paste was placed in the root canals. Radiographic control and replacement of Ca(OH)2 paste took place at 15-day intervals. The root canals were obturated 1.5 months after the first appointment. Recall radiographs were taken 0.5, 1.5, 3, 6, and 12 months after the obturation. All radiographs were taken for each case under constant conditions by using a direct digital radiography system. In each case, the preoperative, postoperative, and control and recall radiographs were digitally registered and pairwise subtracted. The resulting images were further processed by using contrast enhancement and pseudocoloring methods. Changes to the periapical tissue structure were easily detectable by using the above-mentioned methodology, even during short time intervals.

A Retrospective Study Comparing Clinical Outcomes after Obturation with Resilon/Epiphany or Gutta-Percha/Kerr Sealer

“…A more recent method of assessing outcome is through digital subtraction radiography. This technology is able to indicate periradicular changes and demonstrate healing (34), but no criteria have been validated for the determination of success and failure. Digital subtraction also requires standardized radiographs, which are often not feasible in a retrospective study.…”

Digital and Advanced Imaging in Endodontics: A Review

“…No differences were found in the length of canals visible (13). There are many studies comparing various systems with regard to working length determination (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26) and accuracy of detection of periapical lesions (27)(28)(29)(30)(31)(32). Most of these studies used objective criteria (measurements) to test the diagnostic quality of images produced by various techniques.…”

“…Evaluation of the effect of root canal treatment on periapical lesions by conventional and subtracted digital radiographic images of clinical cases showed that a significantly better observer agreement was achieved by digital subtraction radiography (28). Another study to evaluate digital subtraction radiography to monitor progress of chronic apical periodontitis using preoperative, postoperative, control, and recall radiographs, which were contrast-enhanced and subjected to pseudocoloring, indicated that even changes occurring over a short period of time could be detected (29). Changes to the periapical tissue structure were easily detectable by using the abovementioned methodology, even during short time intervals (29).…”

“…Another study to evaluate digital subtraction radiography to monitor progress of chronic apical periodontitis using preoperative, postoperative, control, and recall radiographs, which were contrast-enhanced and subjected to pseudocoloring, indicated that even changes occurring over a short period of time could be detected (29). Changes to the periapical tissue structure were easily detectable by using the abovementioned methodology, even during short time intervals (29). Direct digital radiography (DDR) and telephonically transmitted images versus conventional radiography in the detection of induced periapical lesions showed that there were no statistically significant differences in diagnostic accuracy of archived digital images, transmitted images, and conventional film images (30).…”

Estudo da viabilidade do emprego da técnica de subtração radiográfica digital em radiografias periapicais com registro a posteriori

“…Outro fator a ser considerado é o ruído estrutural ou anatômico, o qual depende da adequada sobreposição das imagens. Para ser efetiva, a subtração deve ser precedida por equalização do contraste e correção geométrica em ambas as imagens que serão sobrepostas (Mikrogeorgis et al, 2004). de pixels e não requer processo de segmentação antes do alinhamento.…”