Access and instruments for endodotics in posterior teeth Flashcards
Pre-treatment assessment includes
Clinical assessment
Radiographic assessment
Two questions to ask during pre-treatment assessment
Can we isolate tooth with rubber dam?
Is tooth restorable following the endodontic treatment?
Clinical assessment - endodontic diagnosis
Caries Restorations Status of remaining tooth structure -amounts -cracks -structural durability Rotation or tilting of tooth Mobility Periodontal pocketing Status of mucosa -swollen -red/ inflamed -sinus tract TTP? Colour change?
Parallax
Can be used to determine difference between canals which overly each other on radiograph e.g. premolars, mesial canals in lower molars
Can be used prior to or during treatment
MBD rule
When xray tube moves to Mesial, the Buccal canal moves to the Distal in the image
SLOB rule
Same = lingual
Opposite = buccal
The xray tube moves mesially so the lingual (palatal) canal moves in same direction (mesially) and buccal canal moves in opposite (distal) direction
Preliminary treatment
Ensure tooth is adequately restored
-restore any caries
-replace any defective restorations
Dismantle coronal restorations (if appropriate)
-any suspect indirect restorations should be removed and replaced with either new core build-up or a provisional indirect restoration
Access cavity preparation criteria
No undercuts
Smooth axial walls
All canal orifices visible
Objectives of an access prep
Ideal access forms funnel to allow instruments straight entry into canal orifices and into apical third
Allows safe irrigation
Allows ease of shaping
To straighten out curves to allow more accurate working length determination
Lower premolars
30% of lower premolars have 2 root canals
It is the lingual canal which is often missed due to access
Ensure access is adequate to identify a lingual canal if present
Where are upper premolar canals located
One buccal, one palatal
Where are lower premolar canals located
One canal buccolingual
Where are upper first molar canals located
4:
- one lingual
- one buccal
- 2 mesio-buccal (main and secondary)
Where are upper second molar canals located
3:
- one palatal
- one occlusobuccal
- one mesiobuccal
Where are lower first molar canals located
3:
- one mesiobuccal
- one mesiolingual
- one occlusodistal (central)
Bur for access through porcelain
Diamond bur
Bur for access through metal
Metal cutting ‘jet’ bur
Bur to improve visibility
Long Neck Bur
Bur for access through dentine
Long-shank bur
Bur for access into pulp chamber then ‘de-roofing’
Safe tipped endo-z bur
Bur for smoothing sides of access cavity
Endo-z bur
Multi-rooted teeth
Each root should have its own reference point on occlusal and its own working length
Anti-curvature filing
Preferential filing away from high risk areas
Recommended sequence for canal negotiation in a sclerosed canal
Initial negotiation with size 08 K file to 1/2 way
Negotiation with size 10 K file 1mm less
Negotiation with size 10 H file 1mm less again
Entrance to canal is becoming widened
Re-negotiate with size 08 K file 1/2 way
Re-negotiate with size 10 K file 1mm less
Initial prep with GG size 1
Negotiate with size 08 K file 2/3 of way down canal
Negotiation of size 10 K file 1mm less
Negotiation with size 15 H file 1mm less again
Preparation with GG size 2
Preparation with GG size 3
Negotiate with size 08 K file 3/4 of way down canal
Negotiation with size 10 K file 1mm less
Negotiation with size 20 H file 1/2 way down canal
Negotiation with size 20 K file 1mm further
Preparation with GG size 4
