The association between root canal filling and treatment outcome.

The aim of the study was to evaluate the technical quality of endodontic treatment per- formed by postgraduate students in Karolinska Institutet, Stockholm, Sweden during the years (2008-2011) and to evaluate the treatment outcome. In addition, possible influencing factors to treatment outcome were analyzed. All maxillary first molars that received endo- dontic treatment between 2008 and 2011 were included in the study. Pre, post and follow up radiographs were collected.The apical status (PAI-score),the quality of the root canal treat- ment (RCT) and the treatment outcome were assessed. Analysis of the treatment outcome in relation to the quality of root canal treatment and other possible influencing variables was performed by Chi2 or Fisher's Exact test, and the statistical significance was set at P<0.05. A total of 73 teeth were included in the study. Out of these, sixty-three teeth (86,3 %) had periapical lesions at the time for RCT. An initial root canal treatment was performed in 46 teeth (63 %) and 27 teeth (37 %) were retreated.There was no significant as- sociation between the outcome and the type of treatment.The majority of the RCT's (58 %) had good seal and correct length. In total, the treatment outcome was successful in 59 (81 %) of the cases. The success rate was 88% in cases with high quality root fillings, compared to 71% in cases with less good quality.There was a non- significant trend (P =0.066) of an association between RCT quality and treatment outcome. In conclusion the association between the quality of the root filling and the treatment outcome was not verified with statistical significance, but the results indicate a trend that satisfactory root fillings are associated with a favorable outcome.This study was limited by its retrospective nature and a relatively small sample size.