7De Chevigny C,Dao TF,Basrani BR,et al.Treatment outcome in endodontics:the Toronto study-phase 3 and 4 :orthograde retreatment[J].Journal of Endodontics, 2008,34 : 131 - 137.
8Farzaneh M,Abitbol S,Friedman S.Treatment outcome in en- dodontics :the Toronto study-phase 1 and 2 :orthograde re- treatment[J].Journal of Endodontics,2004,30:627-633.
9Ng YL,Mann V,Gulabivala K.Outcome of secondary root canal treatment :a systematic review of the literature[J].Inter- national Endodontic Journal,2008,41:1026-1046.
10Rahbaran S,Gilthorpe MS,Harrison SD,et al.Comparison of clinical outcome of periapical surgery in endodontic and o- ral surgery units of a teaching dental hospital :a retrospec- tive study [J].Oral Surgery Oral Medicine Oral Pathology, 2001,91 (6) :700-709.
