Biomechanical Preparation - Irrigation Flashcards
Name 3 reasons to use L.A.
- Vital pulpal tissue
2, Placement of rubber dam is painful - Tooth is TTP
What is the most common type of L.A used?
Lignocaine with adrenaline
What may be used if the patient’s PMH contraindicates use of adrenaline?
Scandonest (lignocaine with no adrenaline)
Name 3 functions of irrigation during canal negotiation and enlargement
- Lubricate instruments
- Flush out debris
- Dissolve organic matter
Name 2 functions of irrigation during mechanical shaping to final taper
- Flush out debris
2. Dissolve attached inorganic matter (Smear layer)
Name 2 functions of irrigation after mechanical shaping
- Dynamic irrigation
2. Penetrate canal peripheries
What are 3 commonly used irrigants in endodontics?
- Sodium Hypochlorite (NaOCl) 2%
- Chlorhexidine 2%
- Ethylene-diamine tetracetic acid (EDTA) 17%
Describe NaOCl mode of action
- Forms nitrogen, formaldehyde and acetaldehyde on contact with tissue proteins
- Proteins dissolve and hydrogen replaced by chlorine forming chloramines
- Chloramines have antimicrobial action
Describe the delivery of NaOCl
- Capable of dissolving inorganic tissue
- Safety sided syringes with Luer Lock design used
- Prevent extrusion in periapical tissues (2mm short of WL)
Describe the 3 common potential symptoms of a hypochlorite incident, if maxillary antrum is not involved
- Severe immediate pain
- Swelling
- Profuse bleeding interstitially and through the tooth
Name 4 potential ways to tell if a hypochlorite incident involves the maxillary antrum
- Haemolysis
- Ulceration
- Inhibits neutrophil migration
- Damages endothelial cells
Name 5 ways to prevent hypochlorite incidents
- Pre-op IOPA and determining correct WL
- Straight line access
- Side vented, screw on needles
- Needles should be passive and not reach WL
- Deliver irrigant with minimal pressure
Describe the management of hypochlorite incidents
- Stop irrigation and reassure patient
- Irrigate canal with copious amounts of saline or water
- Dry, dress and temporarily restore
- Adverse incident (IR1) form must be completed
- Follow up is essential at 1 day, 1 week and there-after as necessary
Describe chlorhexidine as an irrigant
- Low level toxicity
- Binds to hard and soft tissue increasing substantivity
- Lacks tissue dissolving property and does not remove smear layer
- Possible allergic reactions
Describe the mixing of NaOCl and chlorhexidine as irrigants
- Avoid
- Impairs disinfection and seal of root filling
- Precipitate forms which is potentially carcinogenic
Describe EDTA as an irrigant
- Dissolves inorganic tissue
- Chelates heavy metal ions in biofilm and degrades biofilm on un-instrumented walls of root canal system
- Mild antibacterial effect
- Extended use may weaken the tooth
What is the Smear Layer?
A surface film of debris retained on dentin and other surfaces after instrumentation with either rotary instruments of endodontic files
What does the Smear Layer consist of?
Dentin particles, remnants of vital or necrotic pulp tissue, bacterial components and retained irrigant
Name 3 types of irrigation techniques
- Manual agitation
- Mechanical agitation
- Fluid delivery
Describe how the patient should be cared for between visits during RCT
- Tooth should be dressed to protect canals
- Intra-canal medicaments are necessary
- Cotton wool should be used to prevent temporary dressing getting into canal
- Temporary restorations may be used
What is the medicament of choice between appointments?
Calcium hydroxide
Name 4 reasons hypocal is a good inter-appointment medication
- Alkaline so good antimicrobial
- Dissolve organic tissue
- Easy to remove
- Osteogenic effect
Name 2 inter-appointment medications which are less commonly used than hypocal
- Steroids
2. Iodine Potassium Iodide
When is iodine potassium iodide useful as an inter-appointment medication?
Refractory cases as iodine has effects on E. Faecalis which is prevalent in recurrent cases
