LA/ Isolation for root treatment Flashcards
Mechanical prep stages
- LA
- Isolation
- Access cavity prep
- Location of canal orifices
- Straight line access
- Prepare ‘glide path’ coronal 2/3
- Opening of corornla 2/3
- Prepare ‘glide path’ full length
9/ Working length determination - Shape canal to working length (apical prep)
- Determination of MAF
- Step-back prep (every 1mm)
Chemical prep
To flush out remnants of pulp tissue & debris created during mechanical prep
To dissolve residual pulpal tissue
To kill bacteria and remove bacterial biofilm
To clean parts of RC system which are inaccessible to mechanical instrumentation
To faciliate instrumentation and prevent RC blockages by acting as lubricant
To remove smear layer
Obturation
Filling canal with 3-dimensional filling
Completely seal all anatomical parts
Prevent reinfection of RC system by denying access to oral bacteria
Resolution of signs and symptoms of disease
Restore integrity of tooth
LA: maxillary teeth
Labial infiltration
Expect blanching
Around apex of tooth being worked on
Palatal infiltration only recommended if px still feels pain
LA: mandibular molars
ID block (IAN block)
Long needle
Px should feel tingling sensation in corner of lip and part of tongue
LA: Mandibular premolars
Mental nerve block & ID block
Mental nerve block like infiltration
Isolation
RD/ Clamp/ Oraseal
- control of saliva
- before access into pulp chamber
LA: maxillary incisors/ canines
Infiltration
Isolation: Before commencing RCT
- fully restore tooth
- evaluate possibility of placing efficient RD
Access cavity prep
- Clinical assessment
- Radiographic assessment
- Dismantle coronal restorations
- Access cavity prep
- no undercuts
- smooth axial walls
- all canal orifices visible
RD placement after access cavity prep
Indirect restoration
Position of tooth
Having visibility of neighbouring teeth will help align long axis of bur correctly
Access cavity
To create smooth, straight-line path to canal system and, ultimately, the apical third
Cutting access through full coverage restorations
Crown may mask actual orientation
Vision may be limited
Excessive cutting
Lateral perforation
Removal of extra-coronal restorations
Considered when: -caries is extensive and restorability questionable Marginal deficiencies result in leakage Difficulty locating canals New crown planned after RCT
Locating canal orifices: magnification and instruments
Magnification -loupes -dental operating microscope Instruments -endodontic explorer -rose-head bur -gates glidden drills -stainless steel files -nickel-titanium files
Straight line access
Reduces stress on instruments to reduce chance of instrument fracture
< chance of procedural errors
Simplifies treatment by providing clear path of insertion for instruments
Opening of coronal 2/3
Removal bulk of infected pulp tissue and dentine
< risk of pushing infected debris apically or through to peri-radicular tissues
Elimination of interferences in coronal 1/3, thus minimising risk of blockage apically
Early introduction of irrigants into apical portion of canal
Easier negotiation to working length
> tactile feedback apically
Prepare glide path
Smooth radicular tunnel from canal orifice to apical constriction
Minimal size should be ‘super loose n.10’ endodontic file (purple)
Lack of glide path
Ledge formation
Transportation
Zip formation
Perforation
Working length determination
To enable root canal to be prepared as close to apical constriction as possible
Ideal terminus for RC prep is junction between RC and periodontium - only identifiable histologically
-root morphology
-radiographic interpretation
Root treatment should end at
Apical constrictions
0.5-1mm shorter than radiographic apex
Over-instrumentation
Damage to root apex and periapical tissues
Extrusion of debris which may contain micro-organisms, elements of necrotic pulp, and infected dentine chips
Presence of excess root filling material in PA tissue which may act as foreign matter
Method of determining working length
Measure pre-op radiograph Tactile feedback of apical constriction Diagnostic or working length radiograph Electronic Apex Locator (EAL) Paper point
Paper point
Observe blood/fluids on instrument tip or anywhere on a paper point
Locating apex
Careful study of high quality radiographs
Magnification of radiographs, changing contrast and light
Keeping apical anatomy foremost in your mind
Use tactile sense to locate apical constriction
Observe blood/ fluids on instrument tip or anywhere on paper point
Use and understand apex locator
