Obturation is the three-dimensional filling of the prepared, disinfected root canal system. The goal is to eliminate residual canal space and prevent re-infection from coronal or apical ingress.
- Entomb residual micro-organisms and prevent nutrition/reinfection.
- Create a fluid-tight seal apically, laterally, and coronally.
- Provide a stable base for the coronal restoration.
Gutta-percha (GP) is the universal solid core: a thermoplastic, biocompatible polyisoprene blended with zinc oxide and barium sulfate for radiopacity. GP alone does not seal — it is compacted against a root canal sealer.
The sealer fills the space between GP and dentine walls, including lateral canals and anatomical irregularities.
- Zinc oxide eugenol (ZOE) — traditional; good track record.
- Calcium hydroxide (e.g., Sealapex) — biological advantages, some solubility.
- Resin-based (e.g., AH Plus, AH 26) — low solubility, strong adhesion, common default.
- Bioceramic / calcium silicate (e.g., BC Sealer, Endosequence BC, TotalFill, BioRoot RCS) — biocompatible, hydrophilic, sets in moisture, widely adopted.
- Matched cone to the final shaping file, coated in bioceramic sealer.
- Seat to working length, sear off coronally.
- Advantages: simple, less heat damage, bioceramic biocompatibility.
- Caveat: relies on sealer flow into lateral anatomy.
- Downpack with a heat source (System B), backfill with thermoplasticized GP (Calamus, Obtura, BeeFill).
- Dense, 3D fill; historic gold standard.
- Technique-sensitive; risk of overextension and vertical root fracture in thin roots.
- Master cone + spreader + accessory cones.
- Old technique; largely superseded except in teaching contexts.
- Cross-linked GP carrier with surface GP; heated in a dedicated oven.
- Fast; good for narrow curved canals.
- Retreatment can be more challenging.
- Apical GP within 0–2 mm of the radiographic apex (avoid extrusion).
- Homogeneous radiopacity along the canal length.
- No voids at the GP–dentine interface.
- Restoration placed within the same visit (coronal seal).