A prospective cohort study of endodontic treatments of 1,369 root canals: results after 5 years.

OBJECTIVE The purpose of this prospective study was: 1) to follow-up a large number of endodontic treatments performed by a single operator, periodically checked over a 5-year period; and 2) to correlate outcome to a number of clinical variables. STUDY DESIGN This prospective study included all consecutive cases during the selected time period. All cases were followed regularly for a 5-year period. At the 5-year end point of the study, 470 patients with 816 treated teeth and with 1,369 treated root canals were available for evaluation. RESULTS The overall rate of success among the 816 teeth/1,369 root canals available for evaluation was 88.6%/90.3%. The success rate for 435 teeth/793 root canals undergoing vital pulp therapy was 91.5%/93.1%. Teeth/root canals with necrotic pulp but without detectable periapical bone lesion were successfully treated in 89.5%/92.3%. If the pulp necrosis was complicated by apical periodontitis, the success rate fell to 82.7% for the teeth and 84.1% for the root canals (P = .037). Teeth with periapical lesion <5 mm had a success rate of 86.6%, and in cases where the lesion was ≥ 5 mm the rate of success was 78.2%. CONCLUSIONS More severe disease conditions negatively affects outcome. An optimal working length was identified. Excess of root canal filling material decreases success. Infected pulp space should be treated with an effective intracanal dressing. The quality of the coronal restoration or the placement of intracanal post retentions does not affect treatment outcome.