Evaluation of cases in which bacterial reduction was not achieved by conventional retreatment methods

Abstract

Abstract : We examined cases in which bacterial reduction by common retreatment methods was unsuccessful. In the 300 cases studied, bacterial reduction was not achieved in 12 teeth (4%), all of which showed persistent presence of root canal bacteria. The 12 cases were divided into three types : affected teeth with apical patency of #60 k-file or larger, affected teeth that showed apical radiolucency with a size of the little finger or larger, and patients with significantly impaired so-called host resistance including those who were receiving anticancer drugs or taking steroids for incurable diseases.