CLINICAL RESEARCH Treatment Outcome in Endodontics—The Toronto Study. Phase II: Initial Treatment

The 4to 6-yr outcome of initial (first-time) endodontic treatment was assessed for Phase II of the “Toronto Study.” In total, 442 teeth were treated by using flared preparation and vertical compaction of warm gutta-percha or step-back preparation and lateral compaction. With 126 teeth excluded (discontinuers: deceased and relocated patients), 163 dropouts, and 31 extracted, 122 (48% recall) were examined for outcome: “healed” (no apical periodontitis [AP], signs, symptoms) or “diseased” (AP, signs, or symptoms). Phase II was analyzed separately and combined with Phase I (n 242), using Chi-square and Fisher’s exact tests (p < 0.05). The healed rate (combined sample, 85%) differed significantly for preoperative AP (absent, 93%; present, 79%), treatment technique (flared preparation and vertical compaction, 90%; stepback preparation and lateral compaction, 80%), gender (females, 90%; males, 79%), number of roots (1–92%; >2–81%), and root-filling length (adequate, 87%; inadequate, 77%). Logistic regression revealed increased risk of disease for preoperative AP (odds ratio 3.3) and technique (odds ratio 2.3). This study confirmed AP and highlighted treatment technique as the main predictors of outcome in initial treatment.