5. Sodium Hypochlorite Extrusion Flashcards
What are common symptoms as a result of sodium hypochlorite extrusion?
pain
swelling
ecchymosis
haemorrhage
neurological complications
airway obstruction
Where does ecchymosis manifest in sodium hypochlorite extrusion?
along course of superficial venous vasculature
What are rates of sodium hypochlorite extrusion?
Rate - less than 50 cases in almost 40 years and we do millions of RCTs every year
What are risk factors of sodium hypochlorite extrusion?
Excessive pressure during irrigation - risks pushing solution into peri-radicular tissues
Needle locked within the canal - can risk pushing solution forward
loss of control of working length
larger apical diameters - root resorption, immature teeth
Anatomical factors
Higher NaOCl concentration
Why can pressure cause hypochlorite extrusion?
If pressure is great enough to cause hypochlorite to cross the vascular wall and enter the blood supply then we end up with hypochlorite being passed through the vasculature which leads to ecchymosis
What facilitates passage of hypochlorite through the vasculature?
Facial venous drainage anatomy - it occurs when the pressure generated by the positive pressure irrigation delivery system at the periapex exceed the venous pressure in sueprifical veins of neck
When will hypochlorite enter venous vasculature?
If the pressure generated by the needle and syringe system at the peri apex is greater than the venous pressure in surperifical neck veins
What is the flow rate of superficial veins of neck?
1m/15 seconds
How do we avoid forcing hypochlorite into venous vasculature?
We want to ensure we never lock the needle and dont exceed flow rate of 1ml/15 seconds
Why can we risk hypochlorite accident if we lose control fo working length?
if we aren’t aware of working length and needle length we can penetrate the apical aspect of the tooth - we must ensure if we aren’t aware of needle length we avoid coming into close proximity of apical anatomy
How do we ensure we dont loose control of WL?
we need to make sure we establish a WL before starting and make sure the needle is a few mm short of WL
How do we control how far needle goes into canal?
use rubber stop or bend needle short of EWL (>2mm from WL)
What teeth must we take care on when doing RCT?
teeth with root resorption
immature teeth
pre existing perfs
What happens if root tip lies within maxillary antrum?
must proceed with caution!!! - use much less pressure to prevent extrsion of NaOCl
How do we manage a sodium hypochlorite accident?
- stop all tx
- keep calm and dont alarm pt - get consultant
- let pt know what has happened and reassure them that we will provide immediate management
- if pain is present then we can consider LA block
- if profuse bleeding through RC then we allow this to occur until haemostasis occurs
- Place steroid containing intracranial medicament in canal with no pressure
- no obturation occurs - we seal coronal access cavity
- pain relief reduction of swelling nd preventing infection is most important
What advice do we give to pts who have had hypochlorite accident?
Analgesic advice - ibuprofen or paracetamol
cold compress for first few days
warm compresses for soft tissue swelling and eliminating haemotoma
review after 24hrs
antibiotics
if severe refer
What must we do before using NaOCl?
Carry out careful pre op radiographic assessment to asses for open canals, perforations etc
assess pre endo restorative state of tooth - if we need to do pre endo build up we can compromise isolation
What must we provide pt with when using NaOCl?
Bib to protect clothing - may need more than one
Protective eyewear
What must we use during endo tx as gold standard?
Rummer dam to isolate tooth and ensure sealed well with oraseal
What do we use to seal dam?
Oraseal - we mould this to tooth contour with damp cotton wool
How do we test dental dam seal?
By irrigating with CHX to ensure no leakage
After dam placement what do we do?
get clinician to check dam
What type of needle do we use for irrigation of canal?
Side vented Leur-lok 27G needle
What do we attach leur-lok 27G needle to?
3ml syringe
How fill do we fill syringes?
2/4 full to aid control
What do we use on syringes?
silicon stop or bend needle 2mm short of working length
How do we bring irrigating needle to pts mouth?
behind pts head - never over their face!!
How do we deliver irrigant solution via the needle and syringe system?
We depress plunger with index finger rather than thumb to reduce pressure
