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.
The abruptness of root canal curvature negatively affected the failure rate of ProFile rotary Ni-Ti instruments. The fractographic results confirmed that failure of Ni-Ti files was caused by a single overload during chemomechanical preparation.
This in vitro study utilized India ink dye after clearing to evaluate the extent of apical microleakage following reverse filling procedures. Forty single‐rooted human teeth divided into 4 groups were chemomechanically prepared and obturated, using the lateral condensation technique with gutta‐percha and Grossman sealer. Following obturation, an apicoectomy was performed and retrograde cavities were filled with 4 different materials: Group A: amalgam and varnish; Group B: EBA cement; Group C: Ketac‐cem®; Group D: hot‐burnished gutta‐percha. All teeth were immersed in India ink, decalcified, cleaned, examined through a stereomicroscope, and the depth of linear dye penetration was measured. Statistical analysis showed significantly less dye penetration with EBA cement and amalgam with varnish than with Ketac‐cem and hot‐burnished gutta‐percha.
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