Endo Flashcards
How do you assess a RCT?
Clinically assess- coronal seal, ferrule, swelling/ sinus/ TTP/ mobility/ increased pocketing
Radiographically assess- length and quality of obturation (within 2mm apex, well condensed), bone support, radiolucency.
What is the ideal crown to root ratio?
1:1.5
List some problems post RCT?
Amount of remaining tooth structure
Wide post holes
Endo complications (fractured instruments, perforations, short/ long root fillings)
Coronal micro leakage
How long should an unrestored RCT be left until it needs to be re-root treated?
3 months
What is a post/ core?
Core provides retention for crown, post retains the core (does NOT strengthen/ reinforce the teeth)
What are some indications for post placement?
Incisors/ canines/ widest canal in premolar
4-5mm root filling apically to post
No more 1/3 of root width at narrowest point, 1mm coronal dentine
Sufficient alveolar bone support (half of post length)
Minimum 1:1 post length/ crown length ratio
1.5mm ferrule (height and width of coronal dentine)
What are contraindications of post placement?
Mandibular incisors (thin/ tapering/ narrow mesiodistal roots)
Posterior tooth
Curved canals (perforations)
Insufficient ferrule
What is ferrule?
Encirclement of 1-2mm dentine above gingival level
Describe the qualities of an ideal post design
Parallel sided post (avoids wedging, causing fracture)
Non-threaded (smooth, incorporates less stress to remaining tooth)
Cement retained - buffer between masticatory forces and post/tooth
What are the material options for a post?
Cast metal/ Stainless steel - poor aesthetics, root fracture, corrosion
Zirconia - high flexoras strength/ fracture toughness, difficult retrievability and root fracture common
Carbon/ glass fibre - flex the same as dentine, aesthetic, retrievable, bond to dentine with DBAs.
Describe the process of prefabricated post placement?
No impressions/ lab visit required - 1 appt
Chairside core build-up
Post and core in different materials
Describe the placement of custom posts?
Indirect pattern fabricated from impression of post hole and wax up of post and core in lab /
Casts from direct pattern fabricated in patients mouth (Duralay)
2 appts - impression and fit (temporise between- risk of root canal contamination)
Cast post made in Type IV heat hardened gold
Irrigate canal with chlorohexidine 0.2%, dry with paper points.
Place cement, use firm apical pressure, remove excess cement.
What is a core build up?
The internal part of the tooth built up with restorative material to replace lost tooth tissue (provides retention and resistance for definitive restorations).
What are the material options for core build up?
Composite (used with fibre post)
Amalgam (needs 24 hours to fully set, avoid as retention is required)
Glass ionomer (absorbs water and core expands in size-not used)
What is a Nayara core?
Root treatment is removed, amalgam packed into the canals and tooth is built up (provides retention).
Cannot be prepared until amalgam fully set (24 hours)