ETT 1 Flashcards
When is Endodontic Treatment indicated?
- Deep caries
- Trauma
- Primary periodontal infection
- Elective endodontic treatment to facilitate prosthodontic rehabilitation
Reasons for fracture in ETT
- Loss of tooth structure
- Endodontic irrigants and medicaments
- Bacteria-dentine interactions
- Age-related changes in dentine
- Reduced protective response to loading (Loss of pressoreception or elevated pain threshold)
- Restorative factors
Differences between ETT and vital tooth?
- ETT abutments had higher failure rate
- ETT more likely to fracture
Is a crown needed after endo treatment?
Anterior teeth: No significant improvement in success of ETT
Posterior teeth: Significant improvement in success of ETT
Why do posterior teeth need crown after ETT?
Cuspal coverage prevent fracture when occlusal forces attempt to separate the cusp tips
When should we crown posterior ETT?
- Large magnitude of force
- Proximity to terminal hinge axis (Class III lever)
- Vertical path of loading
When do we not need to crown posterior ETT?
1.No opposing dentition
2. Tooth is out of occlusion
3. Enough remaining tooth structure (Dens evaginatus)
When should we crown anterior ETT?
- Plastic restorative materials have limited prognosis
- Extensive loss of tooth structure
- Aesthetic requirement
Definition of Anchorage
Securing of restoration by supporting abutment
Anchorage can be achieved by
- Mechanical (Preferred): Reciprocal locking of 2 opposing surfaces of abutments
- Adhesive means: Bonding between restoration and enamel/dentine
Quality of enamel/dentine is critical
For mechanical anchorage, there should be
3-4 mm of tooth structure available interproximally
What should you do if there is insufficient tooth structure available?
Foundation restoration: Core build-up portion of a tooth that is prepared for an artificial crown (Post+Core)
How should you restore intact and vital teeth?
Direct restorations (TCR)
How should you restore vital teeth with the lingual cusp partly destroyed?
Reconstruct a conical abutment with CR
CR increment should be limited to 1-1.5 mm only
How should you restore vital teeth with buccal and lingual cusps partly destroyed?
More than 1.5mm CR build-up needed to get conical abutment
Elective endodontic treatment is required
1. Core bonded to pulp chamber
2. Post + Core
What is the Nayer’s technique?
Amalgam coronal-radicular dowel(post) and core technique
- 2-4mm of GP removed
- Fast-setting amalgam condensed into canals, pulp chamber, coronal portion of tooth
- Crown preparation
- Cast restoration cemented over amalgam core
How should you restore non-vital teeth with extensive damage + ferrule?
- Endodontic treatment
- Post + Core
How should you restore non-vital teeth with extensive damage + NO ferrule?
- Endodontic treatment
- Crown lengthening
- Post + Core
Function of a Core
The foundation restoration which restores sufficient coronal anatomy of a vital tooth or ETT
Function of Post+Core
Provides retention and resistance for artificial crown
Post and core systems strengthen the root. True or false?
False
Ideal properties for foundation restorations?
Post
1. Distribute occlusal loads to entire surface of post space
2. Adequately retained within root
3. Well-contrasted on radiographs
4. Retrievable whenever needed
5. Light in colour if root/planned restoration is translucent
6. No health hazard
Core
1. Stable relative to root
2. Resist occlusal loads
3. No health-hazard
What is a ferrule?
1.5mm-2mm of dentine protrudes above gingival level
What is the ferrule effect?
Small cone of dentine protects the root against splitting
What is the most-important feature of a post-core design
Ferrule bracing
Criteria for successful Endodontic Treatment
- No pathologic signs and symptoms
- Normal periapical tissue (via radiograph)
- Signs of decreasing radiographic PA lesion