A retrospective comparison of outcome of root canal treatment using two different protocols.

Objectives: This retrospective study (1) compared the outcome of root canal treatment performed by an endodontist using 1 of 2 different protocols and (2) evaluated the influence of factors affecting outcome.

Study Design: A total of 200 teeth and 489 roots (Protocol A, 83 teeth/200 roots; Protocol B, 117 teeth/289 roots) treated nonsurgically with root canal 4 to 5 years previously were examined clinically and radiographically according to strict criteria. Generalized estimating equations were used to perform logistic regression to analyze data.