Chemomechanical Disinfection Flashcards
name the three steps in biofilm development
attachment
colonisation
biofilm development
name the 5 ways biofilm can become resistant to antimicrobials
antimicrobials fail to penetrate to biofilm
antimicrobials get trapped in biofilm
antimicrobials dont work against non-growing organisms
biofilm organisms displaying resistant genes
stress response to hostile environment
what are the three design objectives of RCT
create continuously tapering funnel
maintain apical foramen in original place
apical opening as small as possible
what are the stages in mechanical preparation of root canal
preparation of tooth
access cavity
create straight line access
initial negotiation
coronal flaring
working length determination
apical preparation
why is sodium hypochlorite used for disinfection in RCT
potent antimicrobial activity
dissolves pulp remnants
dissolves necrotic and vital tissue
disrupts smear layer
what factors influence the function of sodium hypochlorite
concentration
volume
contact time
mechanical agitation
why is the crown down approached used in RCT
if we irrigate coronally first we are much less likely to carry the micro-organisms further apically with the files when shaping
what is the minimum size master file thought to allow adequate irrigation of the apical part of the canal
25-30
name four ideal properties of irrigants for RCT
dissolution of organic and inorganic matter
killing of biofilm microbes
detachment of biofilm
non-toxic to periodontal tissues
what concentration of NaOCl should be used in RCT
3% in GDH
but anywhere between 0.5% to 6%
how is the irrigant delivered in RCT and what is the risk of not using this
needle and syringe that is side vented
if not side vented - risk of hypochlorite accident of it going through the apex
what is the endo-activator
an ultrasonic piece of equipment that delivers the irrigant and also vibrates to dislodge
what are the complications of sodium hypochlorite
can modify organic component of dentine
will not effectively remove smear layer by itself
has effect on organic material
ophthalmic injuries (eye contact)
apical extrusion
allergic reactions
what is used to remove the smear layer
EDTA (17%)
citric acid (10%)
how long is EDTA required to remain in the canal to effectively remove the smear layer
1 minute
