The purpose of this study was to evaluate the effect of apical preparation size and taper on postoperative pain and healing after primary endodontic treatment.
One hundred and twenty patients with asymptomatic mandibular first molars with radiographic evidence of periapical pathology and with a periapical index (PAI) score ≥3 were randomly assigned to 2 groups, group 1 and 2, based on apical enlargement to 2 and 3 sizes larger than the initial apical binding file (IABF), respectively. Each group was further divided into subgroups A and B depending on the apical enlargement taper of 4% and 6%, respectively. Endodontic treatment was performed, and the final apical enlargement in all the groups was performed as follows: group 1A, 2 sizes larger than the IABF with a 4% taper; group 1B, 2 sizes larger than the IABF with a 6% taper; group 2A, 3 sizes larger than the IABF with a 4% taper; and group 2B, 3 sizes larger than the IABF with a 6% taper. Postoperative pain was assessed at 6, 12, 24, 48, and 72 hours. Clinical evaluation and the change in the PAI score on radiographs were assessed at the 3-, 6-, and 12-month follow-ups.
No significant difference in postoperative pain was found. The success rate was lowest (57.1%) in group 1 subgroup A as evidenced by the significant change in the PAI score between group 1 subgroup A and the rest of the groups at the 6- and 12-month follow-ups.
Apical preparation to 2 sizes larger than the IABF with a 4% taper is insufficient and results in significantly lower success rates compared with larger preparation sizes and tapers.
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Published online: May 28, 2021
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