Restoration Of The Endodontically Treated Tooth Flashcards
What clinical assessment should be made of a previously RCT tooth?
Is tooth restorable and can it be isolated
Coronal seal
Amount of remaining tooth structure
Swelling / draining sinus
TTP
Mobility
Increased Periodontal pocketing
What radiographic assessment should be done of the previously RCT tooth?
Quality and length of root filling
- voids
- missed canals
Shape of canals
patency
- fractures instruments
- perforations
Bone levels to support tooth
Crown to root ratio 1:1.5
Any associated pathology
- inadequate root fillings should be re-treated before restoration
What is coronal microleakage and why is it significant?
Ingress of MO’s into the root canal system
- important cause of RCT failure
- significant in multi rooted teeth
- no restoration within 3 months of RCT, should be re-RCT
What are the treatment options available to an anterior tooth with intact marginal ridges after RCT
Composite restoration
Veneer
What are the treatment options available to an anterior tooth with intact marginal ridges + discoloured crown, after RCT
Bleaching and veneer
Crown
What are the treatment options available to an anterior tooth with marginal ridges lost
Core build up, with crown
Post crown
What is the purpose of a post / core
Drawbacks?
To gain intraradicular support for a definitive restoration
- core provides retention for crown
- post retains core
Posts do not strengthen or reinforce teeth
Prep of root canal for a post weakens tooth
What is the ideal clinical features for a post placement?
Endodontic
- no sinus / swelling / abscess
- no ttp
no exposed GP
restorative
- caries free
- 2mm ferrule, 1mm thick and 3/4 diameter
Perio
- no PPD >5mm
- no mobility or furcation
- no BOP at site
occlusion
- 2mm interocclusal space after core placed
- no bruxism / clenching
What is an ideal post to use?
Parallel sided
- avoids wedging
- more retentive than tapered
Non threaded
- less stress to remaining tooth as it is passive
Cement retained
- cement acts as buffer between masticatory forces and post / tooth
What are the different classification of posts
Manufacture type
- preformed/prefacbircated or custom made
Material
- cast metal, steel, zirconia, carbon / glass fibre
Shape
- parallel or tapered
Pros / cons of metal post?
Cheap to fabricate
Poor aesthetics
Corrosion
Radiopaque
Pros / cons of ceramic posts?
Alumina, zirconia
High flexural strength and fracture toughness
Favourable aesthetics
Root fracture common and difficult to retrieve post
Pros / cons of fibre posts?
Glass, quartz, carbon fibre
- flexible
- similar properties to dentine
- aesthetic
- retrievable
- bond to dentine w DBA
- radiolucent
What is a core build up?
Internal part of tooth built up with restorative material to replace lost tooth tissue
Core is then prepared
- provides retention and resistance for definitive restorations
Most common core material?
Pros / cons?
Composite
- good aesthetics
- bonds to tooth structure
- technique sensitive and moisture sensitive
- used with fibre posts
Para post components?
Provisional post
Burn out posts
Parapets drill
Impression post
How can rotation be prevented if there is not much coronal structure to support a post crown
Small vertical groove placed into the canal located in bulkiest area of root
What is the lab prescription for a post crown?
Please construct cast post and core
- parapost colour
Core 6 degree taper
Please leave 2mm space in occlusion for crown
See enclosed registration / opposing impression
Shade!
What should be done in post crown try in?
Check post space for temp bond and clean with parapost
Irrigate with .2% chlorhexadine
Dry with paper points
Ensure post core fits around prep
Check occlusal clearance - may need adjustment
What are the main problems w posts and cores?
Perforation of the RC
Core fracture
Root fracture or cracking
Post fracture
How is post perforation treated?
Repair - more specialist
- internal or external periradicular surgery
Extraction - me
What are the %’s for reasons for post failure?
60% restorative issues
32% periodontal issues
Only 8% due to endodontic issues
ideal radiographic requirements for a post and core?
ENDO
- if prev RCT, good quality with no voids and 4mm GP apically available
Pathology
- no periapical pathology
root anatomy
- 1:1 root post ratio
- post no wider than 1/3 root width at smallest area
- minimal to no curvature of canals
- no root resorption / fractures to root
bone levels
- no / minimal bone loss
- post 4mm subcrestal
coronal
- no caries
- no crown fractures
Disadvantages of metal posts?
Removal of all undercuts needed
- more removal of sound tooth tissue
Lack of flexibility
- more prone to root fracture
- often terminal
- much less retrievable than fibre posts
Disadvantages of fibre posts
Failure
- due to cementation issue
- secondary caries
- chipping of overlying composite core
- ingress of moisture between resin and post
Advantages of direct posts vs indirect posts?
If placed same appt, less risk of microleakage
Reduces number of visits and also chair time
Reduced lab costs
