Apical seal versus coronal seal

the results of the initial study. It was concluded that the apical fluids, with their primary source being blood serum, diffuse into the empty canal spaces, stagnate, undergo degradation and then act as a physicochemical irritant when they diffuse back into periapical tissues. In support of this theory of stagnation, in 1955 Dow and Ingle showed that the majority of the endodontic failures were the result of inadequate or incomplete obturation of the canal space. Indeed, after having immersed extracted sealed teeth in a radioactive iodine solution, the well-sealed teeth did not suffer any penetration from radiographic isotopes. Conversely, massive penetration was observed in the teeth where obturation was defective. This in vitro study established that the situation was similar to that found in vivo, thus confirming the hollow tube theory. A study of treated cases was undertaken at the University of Washington to evaluate success and failure rates over a two-year period. The study also assessed the various factors related to the failures. This study was published for the first time in 1965 in Endodontics, then systematically reviewed in all later editions of the work (2002). The most striking aspect of the study was a reported failure rate of 58% to 66% due to incomplete obturation of the canal. Although similar to Strindberg’s first study (1956) on the same aspect of failure but demonstrating many bias, the Washington Apical seal versus coronal seal