Root canal filling material in periapical lesions: A polarized and fluorescent light microscopy case series

Overfilling of the root canal can cause foreign body reactions and lead to pathophysiological responses. The aim of the study was to investigate the morphological properties of filling materials associated with periapical lesions through light, polarized, and fluorescent light microscopy analysis. This study reports two cases of root canal overfilling associated with unsuccessful endodontic procedures. In case #1, a 36-year-old woman complained of persistent pain in the region of tooth maxillary right first premolar, after extraction. Clinically, the patient was sensitive to any contact in the region. On radiography, a radiopaque area of 4 mm was observed in the apical region. In case #2, a 35-year-old man reported discomfort when pressing the left nostril, with a history of extraction of tooth maxillary left lateral incisor. Clinically, painless and immobile edema was observed in the overlying region. Radiographically, a radiolucent image with defined edges and a radiopaque dot within the radiolucent was visualized. In histopathology, case #1 was conclusive with foreign body granuloma, while case #2 with residual cyst. In both cases, an excisional biopsy of the lesion was performed, with complete resolution of the cases after the follow‑up period. Recognizing the morphological and optical properties of endodontic lesions mixed with endodontic restorative materials is essential for an accurate and reliable histopathological report.