Objective To study the number and incidence of the lateral root-canals and accessory root-canals in localized periodontitis teeth. Explore the role of endodontic lesions in the process of localized periodontitis. Methods Thirty teeth with localized periodontitis(experiment group) and 30 teeth with generalized periodontitis(control group) were collected according to a coincident standard. Before the teeth were extracted, the alveolar bone absorption was analyzed by imageological examination before the experiment. The transparent specimen was made in vitro teeth. The lateral root-canals and accessory root-canals were counted under a dissecting microscope. Results The statistical analysis revealed that the incidence of angular alveolar resorption in the teeth with localized periodontitis(76.7%) was greater than that in the teeth with generalized periodontitis(36.7%) obviously. The incidence of the lateral and accessory rootcanal was 80% and 52% in the teeth with localized periodontitis and generalized periodontitis respectively. The difference between the two groups was significant. Conclusion The lateral root-canals and accessory root-canals were more in localized periodontitis. The role of endodontic lesions and the excess anatomic pathway in the process of localized periodontitis was very important.
