Root Canal Obturation and Coronal Restoration
This domain tests when to obturate, with what, and how the coronal seal is protected.
Timing
Obturation when the tooth is asymptomatic, the canal is dry, and there is no swelling or active exudate. A painful or weeping canal is treated with further cleaning and a medicament, not with obturation.
Techniques and materials
- Warm vertical compaction (Schilder, continuous wave) adapts gutta-percha to irregular anatomy and is well suited to oval canals and C-shapes.
- Carrier-based systems are fast but risk extrusion and are difficult to retreat.
- Cold lateral compaction is predictable in curved canals but may leave voids.
- Single-cone with a bioceramic sealer is technique-sensitive to sealer quality; bioceramic sealers need moisture and are not eugenol-based.
Quality criteria
Length within 0.5-1 mm of the radiographic apex, adequate taper and density, no voids, no overextension. Extruded sealer can be neurotoxic and may impair healing.
Coronal restoration
Immediate coronal seal after obturation; a temporary restoration left for weeks invites leakage. Preserve at least 3-4 mm of gutta-percha before post space preparation and leave 4-5 mm apically. Posterior teeth generally need cuspal coverage; anterior teeth with minimal loss may be restored with composite. When a post is needed, the ferrule effect of 1.5-2 mm of circumferential dentin is more important than post type.
Worked example
A premolar with a completed, dry canal and no symptoms. Obturate with warm vertical compaction, verify length radiographically, place a resin composite core build-up the same visit, and plan a crown because the marginal ridge is lost.
Traps
Obturating over a weeping canal; leaving a temporary restoration for months; preparing post space with a bur that removes all apical gutta-percha; ignoring the ferrule.