Analysis Of Anatomical Morphology And Microbial Colonization Model On Apex In Patients With Failure Of Root Canal Treatment Of Upper Anterior Teeth

Objective: To collect the cases of upper anterior teeth due to failure of root canal treatment,and by studying the anatomical morphology and root canal filling of the root apex of the affected teeth during apical surgery,and observing the characteristics and colonization mode of the bacteria biofilm inside and outside the root canal,to provide reference for further study of etiology and clinical treatment..Methods: From January 2017 to December 2017,the patients with upper anterior teeth who underwent microapical surgery due to failure of root canal treatment were collected from the Department of Endodontics,Guangxi Medical University School.The patients were required to have an observation period of more than 1 year and the results of microapical surgery were shown to besuccessful.The X-ray film and CBCT data of the affected teeth were collected,and the root tip resected during the operation was collected.The root canal anatomical structure and root canal filling were observed by micro-CT scanning and reconstruction,as well as taking photos,combined with X-ray film and CBCT.Finally,the distribution and colonization pattern of bacterial biofilm inthe inner wall of root canal and outside root canal were observed by scanning electron microscope after the root tip was split.Results: A total of 8 cases were included in the inclusion criteria,and 10 apical samples were collected.After analysis of each case,it was found that the cause of treatment failure was not completely cleaned of the root canal and the root canal was not dense during the treatment,and the root canal was dissected,such as the lateral branch of the root canal,the blind spot,and the extra-root biofilm.Each treatment failure has bacterial biofilm in the root canal of the apical region,and its trait changed with the living environment.Conclusion: The persistent causes of apical infection in the upper anterior teeth may be related to the following aspects:1.There were bacterial biofilms that are difficult to clean up in root canal and on the surface of cement outer root canal.;2.There was unclean area between physiological apical foramen and anatomical apical foramen;3.There were lateral root canals that were difficult to clean and fill;4.Large root canal made it difficult to thoroughly clean and tightly filling...