4Baumgardner KR,Taylor J, Walton R. Canal adaptation and coronal leakage: lateral condensation compared to Thermafil [ J ]. J Am Dent Assoc, 1995,126(3) :351 -356.
5Saunders WP, Saunders EM. Coronal leakage as a cause of failure in root canal therapy : a review [ J ]. Endod Dent Traumatol, 1994,10(2) :105 - 108.
6Kerekes K. Radiographic assessment of an endodontic treatment method [J]. J Endod, 1978, 4(7) :210 -213.
7Sjogren U, Hagglund G, Sundqvist G, et al. Factors affecting the long -term results of endodontic treatment [ J]. Endod Dent traumatol, 1994,10 (2) : 105 - 108.
8Tronstad L, Asbjomsen K, Doving L, et al. Influence of coronal restorations on the periapical health of endodontically treated teeth [J]. Endod Dent Traumatol, 2000,16(5) :218 -221.
9Torabinejad M, Ung B, Kettering JD. In vitro bacterial penetration of coronally unsealed endodontically treated teeth [ J ]. J Endod, 1990, 16(12) :566 -569.
10Swartz DB, Skidmore HE, Griffin JA Jr. Twenty years of endodontic success and failure [J]. J endod, 1983,9(5) :198.