Retreatment Flashcards
Root canal re treatment outline
Non surgical root canal re treatment
Disassembly
GP removal
Treatment outcome
Aims of re treatment
To regain access to apical third of RCS and create environment conductive to healing
We need: coronal access (may involve removal or restorations)
Remove all previous obturating materials
Manage any complicating factors like ledges, zips etc
Achieve full working length
Eliminate microbes
Disassembly
Right skill set
Right equipment
Luck?
Indirect restoration-removal of it?
Yes if defective
If satisfactory - decision making
Advantages of leaving it-avoidance.of cost of replacing, rubber dam isolation is easier, occlusion is preserved and pt is used of the occlusion so no changed to that, aeshetics minimally changed
Disadvantages of leaving it:
Crown removes dentinal core so retention and strength is reduced, increases chance.of iatrogenic mishap, restricted visibility, angulation and anatomy could be misleading, post can obstruct the canal, making more difficult, we can miss hidden caries, fracture, additional canal
Removal of a crown by Wamkey Dentsply set
- Locating most accessible spot of the crown (at the cement layer, between occlusal surface of the abutment and inner side of the crown itself
2 drill thin horizontal window in the crown
3enlarge window until cement underneath can be seen
4 deepen the hole until it reaches the centre of tooth preparation
5 extend the hole into horizontal rectangle
6 introduce Wamkey down to the bottom of the slot and rotate on the handle.
Metalift system
For removal of crown
Drilling a small hole in the occlusal surface down to cement layer , then little device is placed through the hole which grips the crown and using forceps supplied, force along the long axis of the tooth, it will break cement.
Post removal-why
To gain access to the apical third
Can be fairly predictable with few complications
Ease of removal depends on-type of the post, location in the mouth material used to cement it
Always good to know when the post was cemented, if/when it came out last (can give idea what cement was used to cement it)
Bonded restorations are much more difficult to remove (especially if it is perio involved tooth)
Consider port type and material
-if on radiograph, post is opaque- could be easier to remove
-if on radiographs-cannot see the post- probably fibre glass-hard to remove and time consuming
Considerations:
1. Location in the mouth and which tooth (more posterior-harder)
2. All restoration around the tooth should be removed before removal of the post (if metal restoration-use ultrasonic)
Removal of metal posts
Ultrasonics
Eggler post removal
Ruddle/gonon removal
Masseran kit
If metal threathed-unscrew
If quartz fibre post- probably has own kit, or pilot hole and piezo reamer
If zirconia and ceramic post- usually irretrievable
Post removal with ultrasonic
Rubber dam
Magnification and illumination
Aim is to reduce the retention using ultrasonic at the interface between the post and the tooth
We should move around the circumference of the post to disrupt the cement along the post/canal wall interface
Due to heat, use copious coolant spray and stop every 15 seconds as too much heat is generated -removal should last at least 10 min with many breaks
Removal of post with other instruments (not ultrasonic)
Post puller:
1. Egglers- device with two sets of jaws that work independently of one another, first grips the core, second push away/applies pressure from the tooth in line with the long axis of the tooth
If cast post or large post-use high speed and bur
Eggler not to be used for removal of screw posts(it will take too much extra dentine)
Ganon/ruddle post removal system-highly effective for removal of parallel or tapered posts, especially if non active performed posts.
Masseran kit- hollow tube with cutting edge, find the tube just bigger than the post, it is slipped over the post and use it down through the cement line or through the dentine. Post should loosen and we should be able to grip it.
Removal of fibre posts
Often come with its own kit
Need magnification
Post removal complications
Inability to remove
If post is removed and tooth is unrestorable
Heat damage to the PDL from ultrasonic
Tooth/root fracture
Perforation of root
Fracture of post and inability to remove it
When access is gained
Remove any residual cement (with ultrasonic) that are blocking the access into RCS/GP
What is limited access
Consider periradicular surgery
Not all teeth are suitable (upper 1-6(mb,dB), lower 1-3)
Operator dependant
Removal of gutta percha
- Solvents-oil of turpentine (very small amount, in luer lock syringe, toxic to tissue, left for 1 min and then use C + file (high carbon steel, brittle, stiff) or 15,20 Hedstorm,.once GP removed, fill again with the oil and clean with paper points), chloroform, halothene, xylene-disolve the GP, but very messy
- Thermal-ultrasonoic, system B
Can generate too much heat, affect tooth/tissue an cause cell death - Mechanical- rotary NITI files (Protaper D (3 files, d1- shortest, d2- middle, d3- longest, use to reach apex, Mtwo Re-treatment files)
Both used in 600 rpm, always crown down, active top is penetrating the GP
