Damla ERKAL, Yunus Emre ÇAKMAK, Maira KOPBAYEVA, Kürşat ER
Clinical Dentistry and Research - 2026;50(2):160-170
Background and Aim: Radiographic assessment is essential for evaluating the technical quality of root canal fillings and periapical status after root canal treatment (RCT). This retrospective cross-sectional study assessed the radiographic quality of RCT in mandibular premolars using panoramic radiographs and investigated the association between root canal filling quality and periapical lesions. Materials and Methods: Archived digital panoramic radiographs were screened, and 205 radiographs (261 mandibular premolars: 34, 35, 44, 45) were included. Two experienced endodontists independently assessed filling length (adequate: 0-2 mm from radiographic apex; short: >2 mm short; overextended: beyond apex), homogeneity, periapical status (lesion absent/present), and iatrogenic errors. A favorable radiographic outcome required adequate length, homogeneous obturation, no periapical radiolucency, and no iatrogenic errors. Interobserver agreement was calculated using Cohen's kappa. Multivariable logistic regression with cluster-robust standard errors identified predictors of periapical lesion presence. Results: Overall, 59% of teeth met the predefined radiographic criteria. Periapical lesions were present in 26.1% of teeth. In adjusted analyses, short fillings were strongly associated with lesion presence (P < 0.001), and iatrogenic errors were also significant (p = 0.015). Tooth 35 showed higher odds than tooth 34 (p = 0.003). Inhomogeneous fillings showed a non-significant trend (aOR = 2.27; p = 0.072), while overextension was not associated (p = 0.327). Sensitivity analysis was consistent and additionally supported filling homogeneity as significant (p = 0.036). Conclusion: In mandibular premolars evaluated on panoramic radiographs, 59% of teeth met the predefined radiographic criteria. Short filling and iatrogenic errors were independent predictors of post-treatment periapical lesions, highlighting the importance of accurate working length control and meticulous technique.
