Development of predictable periapical lesion monitored by subtraction radiography

Abstract

Abstract Forty‐eight teeth of two baboons were used to establish a methodology for the development of predictable periapical lesions. The canines and third molars were used as controls. All pre‐ and post‐operative radiographs were taken using modified Precision® X‐ray beam guiding to maintain exposure geometry. After routine endodontic access preparation, the pulps were damaged 3–4 mm short of the apex, dental plaque was introduced and mixed with pulp debris, and the access opening was closed with amalgam. Control radiographs were taken at 7‐day intervals. Ten experimental and two control teeth were used for each observation period of 1, 4, 8, and 20 weeks. The radiographs were analyzed using computerized temporal subtraction. After the animals were killed, the specimens were processed for histologic examination. In all cases, pulpal necrosis and bacteria were present in the root canal, and in the periapical area adjacent to necrotic tissue. The periapical lesions had a mixture of inflammatory cells, with predominance of plasma cells, lymphocytes and multinucleated cells. Racliographic analysis by subtraction radiography showed hard tissue changes as early as 7 days. The method predictably developed periapical lesions, which could be monitored by subtraction radiography, and there was a correlation established between radiographic and histologic findings.