Root Canal Irrigants and Disinfectants Flashcards
Disinfectant of choice
Sodium hyperchlorite
and also 2% chlorohexidine
Dentin surface modifier
17% EDTA
Ethylene Diamine Tetra- acetic acid
Inter-appointment medicaments
- calcium hydroxide
- double/triple antibiotics
- ciprofloxacin
- metronidazole
- minocycline
Five main characteristics of an ideal irrigant
- remove pathogens and debris
- kill bacteria of all forms
- fluid flush (hydodynamics)
- dissolve organic and inorganic compounds - Facilitates instrumentation
- accessibility
- lubrication - low cytotoxicity
- substantivity
- minimal effects on the physical properties of dentin
two main challenges in disinfection
- complex anatomy
- instrumentation limits
- confined structure - bacterial characteristics
- planktonic vs biofilm
- dentinal tubule infection
pH of the irrigant of choice and concentration?
pH of 11
ph of 9 is when reaction starts occuring
concentration is .5-5.25
difference in lower and higher concentrations with sodium hyopchlorite use
lower concentrations of .5-1% is a sufficient to be bactericidal and dissolve necrotic tissue and does minimal effect to vital tissue
higher concentration 1- 5.25% is more efficient in action but significantly cytotoxic
these are the lower and higher ends
what is full strength concentration of NaOCl?
5.25%
NaOCl component in fatty acid saponification
Basic - sodium hydroxide + fatty acid –>
gives soap and glycerol
- which will also reduce the surface tension
NaOCl component in amino acid neutralization reaction
the NaOH - sodium hydroxide can combine with the amino acids and neutralize –> you get salt and water
NaOCl component in amino acid chloromination reaction
the acidic component (HOCl hypochlorous acid) combines with amino acids and gives –> chloramine and water
three main mechanisms of NaOCl
- fatty acid saponification reaction
- amino acid neutralization reaction
- amino acid chloramination reaction
what mechanisms do you see the organic dissolution action observed?
in the saponification reaction when sodium hypochlorite degrades lipids and fatty acids resulting in the foramtion of soap and glycerol
what to bacterial essential enzymatic sites account for?
they are related to the antimicrobial activity and promote irreversible inactivation by hydroxyl ions and the chlotamination reactoin
importance of chlorine in the action of NaOCl?
it is strong oxidant that presents antimicrobial action inhibiting bacterial enzymes leading to an irreversible oxidation of SH groups (sulphydryl group) of essential bacterial enzymes
is sodium hyperchlorite a selective agent?
no
- so need to be careful about concentration usages
what is a major complication of sodium hyperchlorite?
immediate pain
edema
profuse interstitial bleeding with hemorrhage of the slon and mucosa (ecchymosis)
sodium hypochlorite complication management
- reassure patients
- long lasting anesthetics for pain
- clinical assessment
- establish drainage
- severe may eed surgical decompression to remove necrotic debris and facilitate drainage
- cold compression initially for 1-2 days then warm compression
for complication management do you need to perscribe antihistamine? corticosteroids?
antihistamine – only if sinus tract involved
corticosteroids is controversal
may need prophylatic antibiotics for prevention of secondary infection
other irrigant of choice if contraindication with sodium hypochlorite? its major downfall?
2% chlorhexidine
it CANNOT DISSOLVE ORGANIC MATERIAL – so it can kill bacteria but will not dissolve its fragments and some of these may be left behind even after irrigation
2% chlorhexidine complication
Carcinogenic and heamatotoxic PCA (ParaChloAniline) occurs when mixing ch lorohexidine with NaOCl or heating it
** the precipitation blocks dentinal tububles and compromises the seal of root canal seal
so need to replace NaOCl completely prior to chlorohexidine
mechanism of 2% chlorhexidine? activity depends on?
cationic component attaches to negatively charged cell membrane areas and causes lysis
activity will depend on the pH and also the presence of organic matter as its activity is greatly REDUCED in the presence of organic material
how to avoid PCA if need to use 2% chlorhexidine
- replace NaOCl completely prior to chlorohexidine
- avoid extensive ultrasonic agitation
- avoid heating
dentin surface modifier we use, characteristics, and mode of action
EDTA at 17 % which will remove the smear layer and demineralize dentin suface by 50 um
- CALCIUM CHELATING AGENT USED IN SMEAR LAYER REMOVAL
- has weak antimicrobial effect but less cytotoxic
relationship between temperature and the NaOCl
at 45 degrees celcius - pulp was dissolved as effectively at this temp when used a 1% concentration as opposed to 20 degrees at a 5.25 % concentration
- so we see 100 fold increase in killing efficacy between NaOCl solutions at 20 degrees vs 45 degrees
when is calcium hydroxide used?
this is the MEDICAMENT OF CHOICE (where as sodium hypochloride is the irrigation of choice)
most commonly used intra-canal inter-appointment dressing
mechanism of calcium hydroxide
antimicrobial because –works based upon the HIGH PH of 12.5
