Association between root canal filling quality and apical periodontitis lesion volume: a cross-sectional cone-beam computed tomography study in a Chilean population

Objectives To investigate the association between root canal filling quality and the prevalence and volume of apical periodontitis (AP) lesions in a Chilean population using cone-beam computed tomography (CBCT). Materials and methods This retrospective cross-sectional study evaluated CBCT scans acquired between 2021 and 2024 at a private radiology clinic in Santiago, Chile, for reasons unrelated to this investigation. A total of 830 root canal–treated teeth from 520 patients were analyzed. AP prevalence was recorded and lesion volume was quantified with the CBCT Periapical Volume Index. Fillings were classified as adequate or inadequate, and the canal-to-root diameter ratio was measured 1 mm short of the filling terminus. Associations, correlations, and odds ratios (OR) were analyzed at a 5% significance level. Results Of the 830 teeth analyzed, AP was present in 37.3% ( n = 310). Adequate fillings were associated with a lower lesion prevalence (OR = 0.514; CI 0.383-0.689; p < 0.001). Mean lesion volume was greater in inadequately (65.5 ± 52.3 mm³) than in adequately (50.3 ± 39.0 mm³; p < 0.05) filled teeth. Molars showed the highest prevalence (43.7%). A weak inverse correlation was found between the canal-to-root ratio and lesion volume (ρ = − 0.110; p < 0.05). Conclusions AP affected over one-third of root canal–treated teeth in the study population. Adequate fillings and larger canal-to-root ratios were associated with a lower lesion prevalence and smaller lesion volumes. Clinical relevance AP affected over one-third of root canal-treated teeth in this Chilean population. Adequate root canal fillings were significantly associated with a lower probability of AP and with smaller lesion volume. Larger canal-to-root ratios were associated with smaller lesion volumes.