Viva Flashcards
What are the components of pulp canal sealer
Powder: zinc oxide, precipitated silver, oleo resin, thymol iodide
Liquid: oil of cloves , Canada balsam
What are the components of tubliseal?
Base: zinc oxide, bismuth trioxide, oil, thymol iodide, barium sulfate
Catalyst: eugenol, resin, annidalin
What is the chemistry behind zinc oxide sealers ?
Zinc oxide powder and eugenol when placed into moist root dentine a gel is formed and residual zino oxide powder remains in the gel causing it to set rigidly
What is the down side with PCS?
Contains silver which can stain teeth
What type of sealer does MTA belong to?
Bio ceramic / tri calcium silicate
What are the ceramic powders of MTA called ?
Tricalcium silicate
Dicalcium silicate
What ions are released for the tri and di calcium silicates ?
Ca and OH
Why is MTA said to be bio active?
Because the release of Ca and OH allowed hydroxyapatite crystals to form on the surface in contact with the body fluids
What was the first MTA product to be released and it’s use?
ProRoot MTA Gray by Dentsply
Root end fillings/perforation repair NOT sealer
What is the chemistry behind bioceramic sealers ?
Tri and di calcium silicate + water = colloidal matrix embedded with CaOH and these are continuously released after setting
Approx how long after setting is CaOH released from MTA?
1 month
Is MTA hydrophobic or hydrophilic ?
Hydrophilic
What is the pH of MTA on mixing ?
10.2
What is the pH of MTA on setting ?
12.5
Name a MTA sealer ?
Total fill
List the generations of apex locators and how they function
Gen 1: resistance method by measuring opposition to the flow of DC
Gen 2: impedance method measuring opposition to flow of AC
Gen 3: frequency based using two frequencies to measure impedance
Gen 4: multi frequency to measure impedance eg Morita
Gen 5: propex 2 multi frequency by measuring the energy of the signal
When did the Krasner and Rankow pulp chamber floor laws come in?
2004
How many teeth were examined for the krasner and rankow 2004 laws?
500 permanent teeth with equal distribution between: maxillary mandibular anteriors premolars and molars
Unrestored and restored
What are the pulp chamber location ?
Law of CEJ: CEJ is repeatable landmark for pulp chamber
Law of centrality : always in centre of the tooth
Law of concentricity: pulp chamber walls concentric to external tooth surface
With regards to pulp chamber floor anatomy what are the laws ?
Symmetry 1: canal orifice equidistant from centrally placed MD line
Symmery 2: canal orifice are perpendicular to MD line across centre of pulp floor
Law of colour change: floor always darker than walls
Orifices are located : at the junction between the floor and wall and the angles of the floor-wall junction and at terminus of root fusion lines
Biodentine when first came out was designed for what use?
Dentine replacement
What uses does Biodentine have other than dentine replacement?
Repair perforations
Liner
Apexification
Retrograde root filling
Resorption lesions
Why is Biodentine faster at setting than MTA?
-Tricalcium silicate grains are smaller in Biodentine
-calcium chloride in the liquid of Biodentine
What are the downsides of MTA and Biodentine ?
The pro longed release of CaOH reduce flexural strength
What other term is synonymous with pulp stones ?
Dystrophic calcification
What tooth structure composition do pulp stones resemble ?
Dentine
Where are pulp stones typically found.?
Canal orifice
What is a true pulp stone ?
Stones found close to the apex with tubules surrounded by odontoblast like cells
What is the difference between a free and attached pulp stone?
Free - surrounded by soft tissues
Attached- united to the dentine or secondary dentine is deposited around the stone
What are pulp stones ?
Foci of calcification.
What is different between pulpal sclerosis and pulp stones ?
Sclerosis is a diffuse process and only occurs in dentinal tubules
What is thought to be a cause of pulp stones?
Unknown but related to stimulation of mesenchymal cells by growth factors to undergo odontogensis
What are the two shapes pulp stones usually take on?
Smooth laminations - coronal
Irregular - radicular pulp
How do coronal/smooth pulp stones grow?
Addition of collagen fibres to the surface
How do radicular / rough pulp stones form?
Calcification of existing collagen fibre bundles
They appear rough because the mineralisation front extends along the coarse fibres
What is the cause of pulp stones ?
Unknown but may occur around degenerating blood thrombi / collagen/ degenerating cells
What percentage of luxated teeth with calcific metamorphosis has secondary infection?
7%
Andreasan
Name a paper which refers to calcified mass extraradiculr
Riccuci et al 2005
Harn et al 1998
How can extra radicular calculus deposits form?
- Originated from the sulcus ( more likely if margins alveolar bone not intact)
- Periapical biofilm at the root surface and calcification may occur due to minerals from GCF or exudate
What bacteria are implied in extraradicular biofilm?
-Chromogenic as often it is stained
-Actinomyces species (gram positive filamentous)
-also found filamentous and cocci bacteria
Neuropathic pain mechanism
Peripherally:
increase in the expression or activity of voltage gated sodium and calcium channels which will support action potential generation.
-decrease in potassium channels which would normally oppose action potential generation.
-Increase in excitability, which may allow endogenous stimuli to cause spontaneous pain
What is neuropathic pain?
caused by damage or disease affecting the somatosensory system.
-associated with dysaaethsia abnormal sensations or
-pain from normally non-painful stimuli (allodynia). It may have continuous and/or episodic (paroxysmal) components
