Differences In Evaluation Of Periapical Radiography And Cone Beam CT In Root Canal Treatment Failure Cases

Objective: The purpose of the study is to compare the differences between periapical radiography(PR)and cone-beam computed tomography(CBCT)in diagnosing root canal treatment(RCT)failure cases.To analyze the reason for failure in root canal treatment.To evaluate the differences between PR and CBCT in diagnosing the lesions of the apical periodontitis(AP),To discuss the role of CBCT in root canal retreatment.Methods: The study collected patients’ data from the Department of Endodontics in hospital from November 2016 to September 2017 through the doctor’s workstation.Cases requirements:(1)The tooth have been treated by RCT;(2)The initial diagnosis of the periapical radiography is performed on the tooth,and the CBCT is needed for the further diagnosis and treatment plan;(3)RCT failure was judged based on clinical examination and periapical radiography.The radiography data of RCT failure cases were retrospectively analyzed.The differences between PR and CBCT in analyzing the pathogenesis and state of RCT failure cases were compared.To observe the failure cases with the presence of apical periodontitis and use periapical index(PAI)to grade the AP.At the same time,the destruction of periapical bone were evaluated by means of measuring the axial,sagittal,and coronal CBCT images.To compare the differences in methods for the diagnosis of apical periodontitis.Results: Experiment 1: A total of 210 RCT failure cases’ PR and CBCT images were collected and analyzed.Under-filling teeth and missed root canals mainly account for the failure in RCT.CBCT could judge the quality of root canal filling and the type of root fracture more accurately.The detection rate of missed root canals of CBCT was 14.8% higher than that of PR,and the detection rate of root fracture of CBCT was 5.7% higher than that of PR.Experiment 2: Apical periodontitis was identified in 92.5%and 97.5%of the forty anterior teeth by PR and CBCT.The difference had no remarkable significance.Apical periodontitis was identified in 80.6%and 93.5%of the ninety-three posterior teeth by PR and CBCT,so the difference had remarkable significance.When the O-PAI was l、2,the N-PAI presented different classifications;When O-PAI were 3,4,5,within every grade the range of the longest diameter of bone lesion in all three dimensions varied.Among the three grades,the range of the longest diameter in same dimension was overlapped.Conclusions: Experiment 1: CBCT images were better than PR in analyzing the pathogenesis and state of RCT failure cases,which will offer more significances in root canal retreatment.Experiment 2: In RCT failure cases,CBCT could diagnose more accurately than periapical radiography in apical periodontitis.CBCT could be observed the details of the periapical lesions and adjacent anatomy structures.CBCT could ensure the periapical classification more accurately and provide guidance for effective treatment plan.