Title:
Incidence and impact of painful exacerbations in a cohort with post-treatment persistent endodontic lesions.

Abstract:
Painful exacerbations of persistent periapical lesions have unknown incidence and impact on quality of life. This study examined the incidence and impact of painful exacerbations and evaluated potential predictive factors of pain associated with root-filled teeth with persistent lesions after root canal treatment.
Patients from a university hospital clinic were screened to identify root-filled teeth with periapical lesions at time of treatment and not resolved at least 4 years later. A clinical and radiographic examination and questionnaire survey were conducted. Patient and treatment characteristics and details of pain experience were studied. Statistical analysis was carried out by using SPSS (version 18).
One hundred twenty-seven patients with 185 persistent lesions were recruited. Median age of patients at recruitment was 56 years (range, 21-82 years). Median time since treatment was 5 years (range, 4-38 years). Overall incidence of flare-up (requiring an unscheduled dental visit) was only 5.8% 20 years after treatment. Less severe pain was more frequent, with a combined incidence of 45% pain at 20 years after treatment. Female patients (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.2-6.0; P < .05), treatment involving a mandibular molar or maxillary premolar (OR, 3.7; 95% CI, 1.6-8.6; P < .05), and preoperative pain (OR, 2.9; 95% CI, 1.3-6.7; P < .05) were significantly associated with pain after treatment. The most commonly affected activities during painful exacerbations were eating and tooth brushing, with minimal impact on daily living.
The risk of flare-up among persistent lesions was very low. A lower degree of pain was more common, but generally with minimal impact on daily activities.