Why is gutta-percha always paired with a sealer, never used alone? Gutta-percha points are solid cones — they cannot flow into the microscopic gaps between the cone and the irregular canal wall. The sealer (a paste) fills those micro-gaps and dentinal tubule openings. Without sealer, tissue fluid would seep along the cone-wall interface and reinfect the canal. Teaching: gutta-percha is the core, sealer is the seal — neither works alone.