Purpose: Periapical surgery eliminates the periradicular inflammatory tissue and seals the apical foramen. The present study relates the radiologic size of the periapical lesion, apical resection, and retrograde filling to the middle- and long-term success of periapical surgery.
Materials and methods: In a prospective study, 235 patients and 333 teeth were subjected to ultrasound instrumentation and retrograde filling with silver amalgam. Radiographic measurements were made of the maximum and minimum diameters of 320 periapical lesions before surgery. In the 384 apicoectomized roots, calculations were made of the eliminated apical portion, and in 526 root canals the magnitude of retrograde filling was determined. The patients were subjected to a minimum follow-up period of 12 months, with a mean of 27.8 months (range 12 months to 10 years).
Results: Global evaluation showed a success rate of 73.9% after 12 months. The mean periapical area before surgery was 37 mm(2) (maximum diameter, 7.4 mm; minimum diameter, 5 mm). The mean apical resection was 6.48 mm(2) (height, 2.7 mm; base, 2.4 mm). The mean area of the retrograde cavities was 3.05 mm(2) (long side, 2.25 mm; short side, 1.1 mm). A positive correlation was observed between the dimensions of the lesion and apical resection with the treatment failure. None of the dimensions of the filling cavity was related to treatment failure.
Conclusion: The prognosis of periapical surgery improves with decreasing periapical lesion size and lesser apical resection, and is not dependent on the magnitude of retrograde filling.