A Modified Obturation Strategy Using the Piston Technique With a Calcium Silicate-Based Sealer in the Management of an Immature Necrotic Mandibular Second Molar: A Case Report.

Endodontic management of immature permanent teeth with pulp necrosis is challenging due to open apices and thin root walls. This case report describes an alternative obturation strategy-the piston technique-in which a calcium silicate-based sealer serves as the primary apical sealing material, while thermoplasticized gutta-percha acts mainly as a pressure-transmitting medium to facilitate its apical displacement. A 14-year-old patient presented with tenderness to percussion of an immature mandibular second molar with an open apex and periapical radiolucency. A diagnosis of pulp necrosis with symptomatic apical periodontitis was established. Treatment was performed in two visits. After chemo-mechanical debridement, calcium hydroxide was placed as an intracanal medicament. At the second visit, obturation was achieved using the piston technique, in which calcium silicate-based sealer is combined with thermoplasticized gutta-percha, allowing apical sealing without the need for an artificial apical barrier. The tooth was subsequently restored. At follow-up, the patient was asymptomatic, and radiographic evaluation showed evidence of an adequate apical seal and periapical healing. The combination of a calcium silicate-based sealer and thermoplasticized gutta-percha, as used in the piston technique, may represent a clinically feasible obturation strategy in selected cases for immature necrotic posterior teeth when regenerative procedures are not indicated.