A 50-year-old female patient presented for root canal treatment due to a subgingival fracture of the crown of tooth 12. During the procedure, an unplanned overfilling of the root canal occurred with materials intended for obturation – a resin-based sealer and gutta-percha. After 19 months of observation, healing of the periapical inflammation was noted, despite the lack of significant resorption of the materials mentioned above. The article provides a detailed description of the treatment, as well as possible complications of accidental overfilling, and evaluates the impact of this complication on the therapeutic outcome.

Key words: overextention, overfilling, material resorption, clinical success, resin-based sealer.