Chemomechanical Disinfection Flashcards
(28 cards)
Schilder’s principles
create a continuously tapering funnel shape
maintain apical foramen in original position
keep apical opening as small as possible
purpose of chemomechanical disinfection
eliminate infection/bacteria
remove canal contents
remove smear layer
prevent reinfection
name and describe file motions
filing
reaming
watch winding = back and forward oscillation 30=60*, light apical pressure
balanced force = 1/4 CW, 1/2 CCW, x3 and irrigate
envelope of motion
what is the point in using irrigants
potent microbial activity, dissolves pulp remnants, dissolves tissue, helps disrupt smear layer, clears debris, removes infection
sodium hypochlorite
antimicrobial
0.5-6%
used throughout with mechanical agitation
MDI - mechanical dynamic irrigation
EDTA
17%
removes smear layer and acts as chelating agent with NaOCl
what is the irrigant protocol
3% NaOCl throughout instrumentation, at least 30ml after instrumentation complete with MDI, 10 mins before obturation
17% EDTA 1 min penultimate rinse
3% NaOCl final rinse
what is true reciprocation and how can this be achieved
reciproc, protaper
mimics manual movement, decreased risks associated with continuous rotation in curved canal
increased cutting efficacy
need increased inward pressure
what material used in RECIPROC
NiTi
S-crossed section
non cutting tip
high flexibility
high cyclic fatigue resistance
describe RECIPROC procedure
150 CCW, 30 CW
straight line access, free with full, irrigation
- R25 EWL, 3 pecking motions <3mm, light pressure, irrigate and recapitulate with file
- once 2/3 prepared, determine CWL [apex locator, silver point 10 w xray]
- ensure 10 goes to WL
- finish with R25, no glide path
what is RECIPROC BLUE
heat treatment of NiTi alloy
increased flexibility and safety
name instrumentation complications
blockages
ledges
perforation
apical zipping/perforation
instrument separation
explain blockages
dentine debris packed apically
fix - ensure irrigation
explain ledges
internal transportation of canal, when working short of length or instrumentation of curved canals as straight, leaves apical infected
fix - bypass with small file
explain apical zipping/transportation
tendency of instrument to straighten
over enlargement of outer curve, under prep of inner
prevent - preserving, don’t skip sequence, don’t rotate in curved canals
fails to provide resistance for packing GP, overextended and poorly filled
explain root perforation
hole
excessive pressure, incorrect WL
explain instrument separation
through torsional stress, flexural stress, cyclic fatigue
torsional stress
tip binds and shank continues rotating
excessive friction, torque exceeds critical level
‘clamp one end paperclip and twist other’
flexural stress
file bending in curved canal
‘bending paper clip once’
cyclic fatigue
cumulative flexural stress
repeated bending, generation of tension/compression
results in failure
‘bending paper clip lots’
what is sodium hypochlorite extrusion and what are the symptoms
extrusion of NaOCl into periradicular tissues
causes chemical burns leading to necrosis
symptoms
pain, swelling, bruising, bleeding, haemorrhage, neurological complications, airway obstructions
risk factors for NaOCl extrusion
excessive pressure
needle lock [<1ml/15 secs]
loss of WL control
high conc
large apical diameter/constriction [RR, immature, anomalies]
anatomical factors
proximity to sinus
management of NaOCl extrusion
stop tx, calm, tell pt, reassure
LA for pain, analgesia
allow haemostasis
steroid intracanal medicament [odontopaste]
seal access cavity
priority for pain relief, reduction of swelling, prevent 2nd infection
cold compress 2-3 days, warm compress after soft tissue decreased swelling and elimination of hameatoma
refer if severe
review 24hrs
guidelines for preventing NaOCl
always dam, oroseal, PPE, test with chx
leur lock 27G needle, securely attach 3ml syringe
only 3/4 full
2mm from WL w rubber stop
press with index finger
