Intrabony defects can be the result of parodontitis. In this study we aimed to examine how clot stability is affected by different infrabony defect angles and superficial treatments in regenerative surgery. Methods: Thirty single-root extracted teeth were cut to obtain a section from each tooth. This section was placed in an artificial model containing an infrabony defect with three walls in order to achieve 10 models at angles of 25◦, 37◦, and 50◦. Five root samples for every angle were not subjected any treatment (NT) and five were subjected to root conditioning with a neutral pH solution of ethylenediaminetetraacetic acid (EDTA) at 24%, applied for 2 min. Venous blood was put into the artificial models containing the root sections, and these were placed in an incubator at a constant temperature of 37 ◦C for 2 h. Samples were analyzed by laser confocal microscopy. Results: All samples exhibited signs of retraction. The EDTA group exhibited a plateau trend for infrabony defects, while in the NT group, there was a statistically significant difference between clot retraction and the increase in defect amplitude. Conclusion: The greater the angle of the infraosseous defect, the higher the rate of clot retraction. This showed that EDTA could reduce the influence of the angle of the infraosseous defect.
