end closure.
- A radiograph may be taken to ensure a dense fill to each root terminus (700HFig. 12.23).
- Seal access cavity tightly between appointments to prevent the leaching of calcium
hydroxide, and critically, to prevent the re-entry of micro-organisms from the mouth
which would disturb the process of root end closure. A 3 mm thickness of glass
ionomer cement or composite resin is adequate to provide a bacteria-tight seal.
Cotton-wool fibres should not be allowed to remain at the cavo-surface of the cavity.
REVIEW
- 3 monthly to monitor root end closure. At each appointment the calcium hydroxide
dressing is carefully washed from the canal and the presence of a calcified barrier
assessed by gently tapping a pre-measured paper point at the working length. - Radiographs should be taken to assess the progress of barrier formation.
- If the canal is closed, obturation may proceed. If calcific barrier formation is not
complete, the canal should be redressed for a further 3 months. Calcific barrier
formation is usually complete within 9-18 months, but could take up to 2 years.
Key Point
Root-end closure
- Gives predictable results if infection is controlled and canal sealed bacteria-tight;
- Infection is controlled by irrigation and disinfection;
- Canal is enlarged enough only to allow irrigant access and dense obturation;
- Adds nothing to the strength of the tooth;
- Coronal restoration is critical to long-term success.
Techniques for obturation
Obturation with gutta percha and sealer prevent the re-entry of oral micro-organisms
to the apical tissues. Cold lateral condensation of gutta percha and sealer may provide
satisfactory results in regular, apically converging canals, but in irregular and
diverging canals, a thermoplastic gutta percha technique is required to improve
adaptation. The use of single cone techniques cannot be recommended in any
circumstance.
Manual obturation in apically divergent canal (701HFig. 12.24 (a)-(c)).
- Select a master point and try into the canal. This is usually the widest point which
will reach the canal terminus, and may be inverted in the widest canals. - Dry the canal and lightly coat its walls with a slow setting sealer.
- Soften the tip of the master point by passage through a bunsen burner flame. Insert
the point to the apical limit of the canal and press gently against the calcific barrier to
adapt the softened gutta percha. - Cold lateral condensation with a spreader to within 1 mm of the apical limit of the
canal adding accessory gutta percha cones lightly coated with sealer. Continue
condensation until the spreader can advance no more than 2 or 3 mm into the canal. - Check radiograph to assess the quality of fill before removing excess gutta percha
with a hot instrument and vertically condensing the warm gutta percha at the canal
entrance. Further cold or warm condensation may be undertaken at this stage if
required to obtain a uniformly dense obturation.