This study aimed to evaluate the association of the variables age, gender, arch position, tooth length, root canal amplitude, and periapical lesion size with the occurrence of postoperative signs and symptoms (
pain, tenderness, and
edema) and the use of postoperative
analgesics following root canal treatment with foraminal enlargement in single-rooted teeth with
apical periodontitis. This prospective longitudinal study included 105 patients requiring root canal treatment of maxillary or mandibular single-rooted teeth with periapical lesion. After root canal treatment in a single session,
pain intensity and tenderness were recorded daily for 7 days and on days 14 and 30.
Edema was evaluated by two independent evaluators within 48 h, 72 h, and 7 days
after treatment. Ordinal and logistic regressions were performed (p < 0.05). Female gender (beta = 1.02; p < 0.01), mandibular teeth (beta = 25.50; p < 0.01), medium root canal amplitude (beta = 0.93; p = 0.03), and
edema (beta = 1.88; p < 0.01) were associated with increased
postoperative pain and tenderness, while the use of
analgesics (beta = -1.82; p < 0.01) and time in days (beta = -0.23; p < 0.01) were associated with a decrease in these signs and symptoms.
Edema was considered a risk factor for
analgesic requirement (Odds Ratio [OR] = 61.46; p < 0.01). Factors such as gender, arch position, and root canal amplitude were associated with postoperative signs and symptoms. The use of
analgesics was more required in
edema and was associated with decreased
pain.