Purpose: To analyze the possible causes of previous endodontic treatment failure by microscopic inspection during apical microsurgery.
Methods: Two hundred and eighty-nine teeth of previous endodontic treatment failure were collected from patients in Shanghai Xuhui District Dental Center, between January 2006 and January 2014. All surgical procedures were performed by using an operating microscope, and 238 roots were included in the study. The surface of the apical root to be resected or the resected root surface after methylene blue staining was examined during the surgical procedure and inspected with 26 magnification to determine the state of the previous endodontic treatment by using an operating microscope. Fisher's exact test was used to analyze the data with SPSS 19.0 software package.
Results: Among the 238 roots with periapical surgery, analysis of the reasons for previous endodontic treatment failure included leaky canal (29.41%), missing canal (15.55%), underfilling (15.55%), anatomical complexity (7.98%), overfilling (4.20%), apical fenestration (4.20%), iatrogenic problem (3.36%), apical calculus (2.52%), apical cracks (1.68%) and unknown reasons (15.55%). The frequency of possible failure causes and tooth position were closely correlated (P<0.001).
Conclusions: Apical microsurgery can better inspect possible causes of previous endodontic treatment failure, in order to improve the success rate of endodontic treatment.