Methods: We conducted an initial periapical radiographs of 30 patients who had teeth with pulp necrosis and periapical lesion. Patients were submited endodontic therapy and, immediately after the coronal opening, samples were collected from the root canals with paper cones. The largest diameter of lesions was calculated in millimeters and quantification of endotoxins were evaluated by the chromogenic Limulus lysate assay.
Results: The diameters of periapical lesions range from 1 to 12mm and the amount of endotoxins from 2.49 to 889 EU / mL. The data were subjected to statistical test of Pearson correlation, p = 0.043 and r = 0.372.
Conclusion: There is a positive correlation, however weak, between the amount of endotoxin and the diameter of the lesion. Therefore, the larger the diameter of the lesion the greater the amount of endotoxin present in the root canal.
Keywords: Digital image analysis, Endodontics, Infection, Pulpal disease and endotoxin