Irrigation in Endodontics Flashcards
What do periapical and pulpal infections need to develop?
Bacteria
What are primary root canal infections?
Polymicrobial
- Dominated by obligate anaerobic bacteria
Aims of irrigation?
Killing and removal of microorganisms
Removal of necrotic/inflamed tissue
Removal of dentine debris and smear layer
Provides lubrication and reduces friction for instrumentation
Obstacles in root canal disinfection?
Anatomical complexities
Smear layer
Fluid dynamics
Biofilm and resistant microbiota
Anatomical complexities of RCT?
Only 61% of canal walls are instrumentated
40% of canal walls remain infected after instrumentation
Irregular and complex systems:
- Webs
- Loops
- Cul de sac
- Fins
- Lateral canals
- Apical delta
= Irrigation disinfects majority of the RC system
Smear layer - what is it and what does it consist of?
Created during cleaning and shaping process Covers the instrumented canal walls Consists of: - Inorganic and organic substances - Fragments of odontoblastic processes - Microorganisms - Necrotic debris
Problems the smear layer can cause?
Provides protection for bacteria
Inhibits/delays penetration of irrigant into dentinal tubules
Why is fluid dynamics a problem?
Fluid motion:
- Irrigant only penetrates 1-2mm further than end of needle
- Needle tip needs to be close to apical region
Absence of fluid motion:
- Stagnation plane
- No flushing of debris/penetration of irrigant into the apical region
Rules for irrigation?
Use a side-venting needle Use a Luer-lok syringe Keep needle tip moving to prevent it wedging and forcing irrigant through the apex Use gentle pressure If the needle binds - stop Constant agitation to improve fluid flow Size 27/30 gauge needle
How to help fluid dynamics?
Consider using a GP point to improve irrigant exchange in the apical region
What is a biofilm?
What is a biofilm extracellular polymeric substance (EPS)?
Any group of microorganisms in which cells stick to each other on a surface
- Adherent cells are frequently embedded in a self produced matrix of extracellular polymeric substance (EPS)
Biofilm EPS = A polymeric conglomeration composed of extracellular DNA, proteins and polysaccharides
Microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism = single cells that may float or swim in a single medium
Difficult to remove as can penetrate into the dentinal tubules
In biofilm, bac are less susceptible to antimicrobial killing than in planktonic phase
What bacterium exhibits a high level of resistance to antimicrobial agents?
E.faecalis
- Can survive monoculture in root canals
- Cultures of root canals irrigated with NaOCl always yielded positive cultures with E.faecalis
- Most frequent species in root canal treated teeth - 90% of cases
- High resistance to NaOCl = failure of endodontic tx
Ideal characteristics of an endodontic irrigant?
Effective antimicrobial action Non irritating to the periapical tissue Stable in soln Prolonged antimicrobial effect Active in presence of blood, serum and protein derivatives of tissue Low surface tension Not stain tooth Non-toxic Cheap Easy to use
When to prepare the canal?
When canal is flooded with irrigant
Types of irrigants?
NaOCl EDTA Clorhexidine Iodine potassium iodide MDTA Hydrogen peroxide Photo-activated disinfection (PAD)