Obturation of the Cleaned and Shaped Root Canal Flashcards
What % of RCT fail due to incomplete obturation?
58%
What does the filling of the root canal system do?
- Prevent the passage of microorganisms and fluid along the root canal and to fill the whole canal system
- Not only block the apical foramina but also the dentinal tubules and accessory canals
How is the filling verified?
the completion of root canal preparation is verified by taking a radiograph with the root canal instrument(s) (or filling cones) inserted to the full working length. The end-point of the inserted instrument (or cone) and the apex should be visible on this verification radiograph.
This radiograph should show the root apex with preferably at least 2–3 mm of the periapical region clearly identifiable. The prepared root canal should be filled completely unless space is needed for a post. The prepared and filled canal should contain the original canal. No space between canal filling and canal wall should be seen. There should be no canal space visible beyond the end-point of the root canal filling.
What is the working length?
the distance from a coronal reference point to the point where the canal preparation and filling should end
Where should preparation end?
Preparation should end at the junction of pulpal and periapical tissue
Where should the WL be?
- WL should be as close as possible to CDJ
- This is usually the narrowest part of the canal – apical constriction
How is the working length determined?
computer - detect PDLs resistance of tissues as a current is passed through
radiograph
What is the WL usually?
0-3mm
usually increases with age
What does >2mm WL of apex increase?
bacteria
When should filling take place?
should be undertaken after the completion of root canal preparation and when the infection is considered to have been eliminated and the canal can be dried.
What qualities should material used to fill the root canal system have?
biocompatible
dimensionally stable
able to seal
unaffected by tissue fluids and insoluble
non-supportive of bacterial growth
radiopaque
removable from the canal if retreatment needed.
What should the filling consist of?
(semi-) solid material in combination with a root canal sealer to fill the voids between the (semi-) solid material and root canal wall.
What is the most common core?
gutta percha
What is gutta percha?
natural rubber
Trans isomer of polyisoprene
What is the composition of gutta percha presentations?
- 20% Gutta-percha
- 65% Zinc Oxide
- 10% Radiopacifiers
- 5% Plasticizers
What technique is most commonly used to fill?
cold lateral compaction