aims and objectives of rct Flashcards
How does a periapical lesion develop?
Cementum prevents the release of toxins along the dentinal tubules and into the PDL but they’re released through the apical foramen and lateral canals
What are the lines of defence against bacteria?
- Pulp- releases reparatory tertiary dentine forming a bridge
- Periapex- tissue fluids, inflammatory exudate, immune cells
What must be considered before RCT?
Restorability of tooth Visibility of pulp chamber and canal space Shape of canal No of roots and canals Presence of any periapical lesion Presence of any previous RCT
What is the aim of RCT?
To prevent or cure apical periodontitis by eliminating the source of infection
What are the objectives of RCT?
Complete removal of irreversibly damaged/necrosis pulp
Dissolution and debridement of!infected tissue by cleansing, disinfecting and shaping
Create optimal shape to allow well-compacted filling (obturation)
What does the RCT procedure involve?
Mechanical prep
Chemical prep- irritants (sodium hypochlorite 1-5%) and inter visit medication (non setting calcium hydroxide)
Obturation
What are the mechanical prep stages?
Local anaesthetic Isolation w oroseal Access cavity prep Location of canal orifices Straight line access Prepare glide path coronal 2/3 Opening coronal 2/3 Prepare glide path full length Working length determination Shape canal to working length Determine master apical file Step back prep (every 1mm)
What does chemical prep involve?
Flush out remnants of tissue and debris
Dissolve residual pulpal tissue
Kill bacteria and remove bacterial biofilm
Clean parts of inaccessible canals
Facilitate instrumentation and prevent blockages by acting as a lubricant
Remove smear layer
What does obturation involve?
Fill canal w 3D filling
Completely seal anatomical parts
Prevent reinfection by denying access to oral bacteria
Resolution of signs and symptoms of disease
Restore integrity of tooth
How is local anaesthetic administered?
Maxillary- labial or palatial infiltration
Mandibular molars- inferior alveolar nerve block
Mandibular premolars- mental nerve block and inferior alveolar nerve block
Why might extra coronal restorations be removed?
Caries is extensive
Marginal deficiency=leakage
Difficulty locating canals
New crown planned after RCT
How are canal orifices located?
Magnification- loupes/microscope
Instruments- endo explorer, rose-head, gates glidden drill, stainless steel file, nickel-titanium file
Why is a straight line access important?
Reduces stress on instruments
Reduces chance of procedural errors
Simplifies treatment- clear path
Why is the coronal 2/3 opened?
Removes bulk of infected tissue
Reduces risk of pushing debris apically
Eliminates interferences so reduces risk of blockages apically
Early intro of irrigants into apical portion
Easier negotiation of working length
Improved tactile feedback apically
What is the glide path?
Smooth radicular tunnel from canal orifices to apical constriction
Should be a super loose no 10 endo file
How is the working length determined?
Different morphology, radiographic interpretation
Apical constriction is 0.5-1mm short of apical foramen
1. Measure preop radiograph
2. Tactile feedback (file large enough)
3. Working length radiograph
4. Electronic apex locator
5. Paper point
Why should over instrumentation be avoided?
Less damage to apex and tissues
So there’s no extrusion of debris (may contain microorganisms, necrotic pulp, infected dentine chips)
So there isn’t excess root filling in the periapical tissue that might act as foreign matter