In this study, we introduced a method for separating teeth and detecting the end of the root and possible lesions around it in periapical radiographic images. Since there is no standard database of periapical radiographic images, we used a dataset containing 50 periapical radiographic images collected. Before starting to work on the data; Data were preprocessed. Then, the proposed algorithm for separating teeth in periapical images, which includes the process of determining the angle of the teeth with the horizontal axis and obtaining the border between the teeth in the images, was investigated.