Endodontics Flashcards
What are the methods of periodic-endo communications?
Perforations
Root apex
Lateral canals
Fractures
Dentinal tubules
What are the ideal properties of an obturation material?
Biocompatible
Dimensionally stable
Unaffected by oral fluid
Insoluble
Radiopaque
What is the composition of gutta percha?
20% GP
60% Zinc Oxide
10% Radiopacifiers
5% Plasticisers
What is the function of a sealer?
Seals space between dentine wall and core
Fills voids and irregularities
Lubricates obturation
What are the ideal properties of a sealer?
Good adhesion
Easily mixed
Bacteriostatic
Insoluble
Radiopaque
No shrinkage
Slow set
How does zinc oxide eugenol perform as a sealer?
Antimicrobial
Free eugenol can be toxic
How does glass ionomer perfom as a sealer?
Bonds dentine
Difficult to remove
Minmal antimicrobial
How does resin perform as a sealer?
Good sealer
Good slow
Slow set 8 hours
How does calcium silicate perform as a sealer?
High pH (12.8)
Biocompatible
Good seal
What are the 9 endo laws?
Centrality
Concentricity
ACJ
Symmetry 1
Symmetry 2
Colour
Orifice Location 1
Orifice Location 2
Orifice Location 3
What is the law of centrality?
Floor of pulp is central to the tooth at the ACJ
What is the law of concentricity?
Walls of pulp chamber are concentric to the external surfaces at the ACJ
What is the law of the ACJ?
The ACJ is the most consistent, repeatable landmark for locating the pulp chamber
What is the Symmetry Law 1?
Orifices of canal are equidistant from line drawn in mesio-distal direction through the pulp chamber floor
What is the exception to the symmetry 1 law?
Upper 6’s
What is the symmetry law 2?
Orifices of canal lie on perpendicular to a line drawn in a mesio-distal direction across the centre of the pulp chamber
What is the exception to symmetry law 2?
Upper 6’s
What is the colour law?
Colour of pulp chamber floor is darker than the walls
What is the orifice location 1 law?
Orifices are located at junction of walls and floor
What is the orifice location 2 law?
Orifices are located at angles in the floor wall junction
What is the orifice location 3 law?
Orifices are located at terminus of root development fusion lines
How can endodontic equipment be classified?
Manually operated
Low speed
Engine driven NiTi rotary
Engine driven adapts to canal
Engine driven reciproc
Ultrasonic
How can endodontic equipment be classified?
Manually operated
Low speed
Engine driven NiTi rotary
Engine driven adapts to canal
Engine driven reciproc
Ultrasonic
What is Nitinol?
Equiatomic alloy of nickel and titanium
What are the special features of nitinol?
Exotic material: does not conform to typical rules of mettalurgy
Superelasticity: application of stress does not result in usual proportional strength
What is the crystal structure of NiTI?
Temperature dependent structures of martensite and austenite:
Martensite= soft and ductile
Austenite= strong and hard
What is shape memory?
Material deformed at one temp then returns to original shape
What are the components of rotary instruments?
Taper
Flute ; groove to collect dentine and soft tissue
Cutting edge
Land; surface between flutes
Relief; reduction in land
Helix angle; angle formed by cutting axis and long axis of files
What is the purpose of irritants?
Remove debris
Lubricate
Dissolve organic and inorganic material
Penetrate to canal periphery
Kill bacteria/yeast
Disrupt biofilm
What does sodium hypochlorite ionise in water to form?
Na+ and OCl-
What is the effect of pH on sodium hypochlorite?
Acid/neutral: HOCl predominates
>9; OCl- predominates
What are the ideal features of obturation materials?
Easily manipulated
Seals canal laterally and apically
Unaffected by moisture/fluid
Sterile
Dimensionally stable
Non-irritant
Radiopaque
Easily removed
What are the ideal properties of sealers?
Tackiness
Easily mixed
Bacteriostatic
Insoluble in tissue fluids
Radiopacity
No shrink on set
Slow set
What is gutta percha?
Transiosomer of poly-isoprene
What are the design objectives
Continuously tapering funnel
Maintain apical foramen position
Apical opening as small as possible
What are the clinical objectives?
Remove infected hard and soft tissue
Prevent re infection
What is endodontic success improved by?
Hypochlorite irrigation
Dental dam
Why is dental dam used in endodontic?
Protects airway
Improves access
Improves efficacy and vision
Prevents contamination
Protects soft tissue
What are the pulpal diagnoses?
Normal
Reversible Pulpitis
Symptomatic Irreversible Pulpitis
Asymptomatic Irreversible Pulpitis
Pulp Necrosis
How does a normal pulp present?
Asymptomatic
Normal thermal response
Vital
How does symptomatic irreversible Pulpitis present?
Lingering pain to stimulus
Pain with postural change (night)
How does reversible Pulpitis present?
Inflamed
Pain to stimulus
Resolves with treatment
How does asymptomatic irreversible Pulpitis present?
No symptoms
Normal response to thermal tests