Re-Endodontics Flashcards
How to diagnose post-treatment disease?
may not be straight forward as you may be dealing with partially treated pulp canals, missed canals or procedural mishaps. These should be included in the diagnostic description.
What is included to enable you to gain a good pain history?
When RCT was fine and if any problems arised
Rubber dam used?
Check for:
- swellings/sinus
- TTP
- Mobility
- PPD > 3mm
- tenderness on buccal palpation
Special tests:
- hot and cold sensitivity
Remember the SLOB radiography rule?
SAME lingual
Opposite Buccal
If you move the x-ray head medially the two roots will move dismally but the buccal one will be the opposite direction of the movement and the lingual will be the one in the same direction
Name the 3 diagnostic categories for post treatment disease?
Previously treated:
- (a)symptomatic PRP
- chronic apical abscess
- acute apical abscess
Name the 4 causes of post treatment disease?
Intraradicular microorganism
Extraradicular infection
Foreign body reaction
True cyst
Name the 9 possible reasons for the canal to have intra-radicular microorganisms?
Poor access cavity design
Untreated major or minor canal
Poorly prepared canals or poorly obturated
Procedural complications
Ledges
Perforations
Separated instrument
Newly introduced microorganisms
Coronal leakage
Name the 8 main reasons for endodontic treatment failure?
- Leaking around intubation
- Non-treated canals
- Underfilled
- Complex canal system
- Overfilled
- Iatrogenic
- Apical biofilm
- Cracks
What is the definition of an extraradicular infection?
Microbial invasion and proliferation into the preriradicular tissues.
- perio endo lesion where pocketing extends to the apical foramina
- extrusion of infected dentine chips during instrumentation
- overextended instrumentation/filling material
Biofilms which grow through the apical constriction and form an external apical biofilm
Extraradicular microbes
What is the defintion of a foreign body reaction?
In the periradicular tissue have been associated with a chronic inflammatory response:
- vegetables
- cellulose fibres
- onturatiob material (sealer or GP)
What is the defintion of a true radicular cyst?
Form when retained embryonic epithelium begins to proliferate due to the presence of chronic inflammation
Can’t tell between abscess, granuloma or cyst - radiographically
Cystic characteristics in a radiograph?
The larger it is, the more likely it’ll be cystic
However, treatment is still the same
Name and deacribe the 2 types of radicular cysts?
True radiculsr cyst:
- an enclosed cavity totally lined by epithelium
- no communication with RCS
- not heal after RCT
Periapical pocket cyst:
- epithelium is attached to the margins of the apical foramen
- cyst lumen is open to the infected canal and hence can communicate directly
- heal after RCT
Name the 7 things beware of when treating a tooth for an RCT?
History of bruxing
History of frequent decementing
Occlusal wear facets
Large/wide RCT/Posts
Large, narrow perio pockets
Can also indicate a perio endo lesion
Look for vertical root fracture
What is the most common cause of failed RCT?
Persistent or secondary infection of the RCS
Secondary intraradicular infections
Microbes are not present in the primary infection but have been introduced later
What species of bacteria can be found as a secondary intraradicular infection?
Propionibacterium
Actinomyces
Prevotella
E.faecalus
Streptococcus
Candida albicans
Fusobacterium nucleatem
Spirochaetes
Different combinations of bacterial can cause different ways of treatment failure
What are the 4 options after diagnosing a treated tooth with lost- treatment disease?
Nothing
Nonsurgical
Extraction
Surgical
When should Do Nothing be suggested for a patients failed RCT tooth?
No signs nor symptoms form the tooth and the radiolucency is not increasing in size
Evidence shows that it has little chance of becoming symptomatic
When should extraction be suggested?
When tooth has an obvious hopeless outlook
When should non-surgical re-treatment be suggested for a failed RCT?
The safer option that surgical
Most benefit with lowest risk
Greatest likelihood of eliminating most common cause (intraradicualr infection)
But could be more costly than surgical treatment and longer
When should surgical treatment be suggested for a patients failed RCT?
Surgery is chosen when no surgical re-treatmebt is not possible, or where the risk to benefit ratio is outweighed by surgery
RCTs can be improved, but somethings can be rectified
What are the aims of root canal re treatment?
Re treatment aims to regain access into the apical 1/3 of the the root canal system and create an environment conductive to healing
Need:
- coronal access (remove restorations)
- remove all previous obstruction material
- manage any complicating factors
- achieve full working length
- eliminate microbes
Should you remove the crown/bridge or not? Advantages and Disadvantages of keeping/removing?
Decision is easier if it is defective or replacement is required
Advantages of retaining the restoration:
- cost for replacement avoided
- isolation is easier
- occlusion preserved
- aesthetics maintained
Disadvantages of retaining indirect resto:
- removes dentinal core reduction retention and strength
- increased change of iatrogenic mishap as restricted vision
- removal of canal obstructions more difficult
- may miss something important
Name the 2 techniques to remove the crown without destroying it?
WAMKEY - dentsply maillefer
Metalift system
What influence the difficulty of post removal?
Fairly predictable
Depends on the post, location in mouth and material cemented with
How to remove a post?
What it was cemented with and when the last time it came out
Bonded restorations are more difficult to remove
Consider the types of post material? Name 2
Dentatus screw
Quartz fibre - more time consuming
What arenthe initial considerations when thinking about how to remove a post?
Location in the arch of the tooth that requires post removal
The more anterior in the arch, the more difficult to remove due to accessibility
To remove a post firt remove all restorative materials all around- use ultrasonics
Explain the way in which you’d remove the metal posts?
Ultrasonics
- eggler post remover
Ruddle/Gonon post remover
- masseran kit
If metal threaded, can often unscrew using Spencer Wells or similar
Quartz fibre posts
- pilot hole then piezo reamer
Zirconia and ceramic post
- often irretrievable
Explain the process of post removal with ultrasonics?
Rubber dam
Magnification and illumination
Aim to reduce the retention sing ultrasonics at the interface between the post and the tooth
Constantly move it around the circumference of the post to disrupt the cement along the post/canal wall interface
Use copious coolant spray
Owing to the heat that can be generated, stop every 15s
What to do if ultrasonics don’t work?
A post puller is required
Explain the Eggler post removal system?
Post puller
Device consists of two sets of jaesnrhay work independently
- first jaw grips the core
- the other jae pushes away from the tooth in line with the long axis
A cast core may need reduced with a high speed hand piece
- not recommended for the removal of screw posts
Explain the Ganon/Ruddle post removal system?
Effective for removing parallel or tampered non-actice preformed posts
Hollow trephine bur played over the trimmed down post
Trephine domes off tip of post to allow specific, matched size extraction mandrel to create a thread onto the exposed portion of the post
The extraction mandrel is attached to the post, the extraction vice is applied to the tooth and post
Turning the screw applies a coronal force
But vice large access in molar/crowded incisors is difficult
Explain how to remove fibre posts?
Often come with drill for removal
Need magnification
Can drill a pilot hole in the long access
Set a silicone stop at the depth of the post on the reamer and slowly take to this length
LN burs v useful
Speed at 600-900rpm
How to remove a fractured post?
Masseran Kit
Name the 6 potential complications of post removal?
Inability to remove
Tooth is unrestroable
Head transmission to PDL from ultrasonics
Tooth/root fracture
Perforation of root
Fracture of post and inability to remove
How to gain access to the RCS on a RCT tooth?
Once coronal access is gained remove any residual cement using an ultrasonic blocking access jntonthe RCS
What should happen if the tooth has limited access?
If not possible to remove lost, surgery can often be performed
Name 3 types of ways to remove GP?
Solvents:
- chloroform, halothane and oil of turpentine
Thermal
- ultrasonic
- system b
Mechanical
- rotary NiTi files (ProTaper D)
Explain how to use chemical solvents to remove GP?
Very small amount in luer lock syringe
Toxic if extruded
Leave in canal for a minute then working into HP with a C+ file or a 15 or 20 hedstrom
When all GP removed, add more solvent into canal and wick out paper points
Explain how to mechanically remove GP from the canal?
Rotary Notice files
- Mtwo R
- ProTaper D
Use at 600rpm
Always crown down
Active tip to penetrate GP
In which order should you use the ProTaper D files?
D1 16mm
D2 18mm
D3 22mm
Removing carrier based systems?
Much more difficult with more errors chance
Guttacore
New