Viva

Question 1

What are the components of pulp canal sealer

Answer 1

Powder: zinc oxide, precipitated silver, oleo resin, thymol iodide
Liquid: oil of cloves , Canada balsam

Question 2

What are the components of tubliseal?

Answer 2

Base: zinc oxide, bismuth trioxide, oil, thymol iodide, barium sulfate
Catalyst: eugenol, resin, annidalin

Question 3

What is the chemistry behind zinc oxide sealers ?

Answer 3

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

Question 4

What is the down side with PCS?

Answer 4

Contains silver which can stain teeth

Question 5

What type of sealer does MTA belong to?

Answer 5

Bio ceramic / tri calcium silicate

Question 6

What are the ceramic powders of MTA called ?

Answer 6

Tricalcium silicate
Dicalcium silicate

Question 7

What ions are released for the tri and di calcium silicates ?

Answer 7

Ca and OH

Question 8

Why is MTA said to be bio active?

Answer 8

Because the release of Ca and OH allowed hydroxyapatite crystals to form on the surface in contact with the body fluids

Question 9

What was the first MTA product to be released and it’s use?

Answer 9

ProRoot MTA Gray by Dentsply
Root end fillings/perforation repair NOT sealer

Question 10

What is the chemistry behind bioceramic sealers ?

Answer 10

Tri and di calcium silicate + water = colloidal matrix embedded with CaOH and these are continuously released after setting

Question 11

Approx how long after setting is CaOH released from MTA?

Answer 11

1 month

Question 12

Is MTA hydrophobic or hydrophilic ?

Answer 12

Hydrophilic

Question 13

What is the pH of MTA on mixing ?

Answer 13

10.2

Question 14

What is the pH of MTA on setting ?

Answer 14

12.5

Question 15

Name a MTA sealer ?

Answer 15

Total fill

Question 16

List the generations of apex locators and how they function

Answer 16

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

Question 17

When did the Krasner and Rankow pulp chamber floor laws come in?

Answer 17

2004

Question 18

How many teeth were examined for the krasner and rankow 2004 laws?

Answer 18

500 permanent teeth with equal distribution between: maxillary mandibular anteriors premolars and molars
Unrestored and restored

Question 19

What are the pulp chamber location ?

Answer 19

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

Question 20

With regards to pulp chamber floor anatomy what are the laws ?

Answer 20

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

Question 21

Biodentine when first came out was designed for what use?

Answer 21

Dentine replacement

Question 22

What uses does Biodentine have other than dentine replacement?

Answer 22

Repair perforations
Liner
Apexification
Retrograde root filling
Resorption lesions

Question 23

Why is Biodentine faster at setting than MTA?

Answer 23

-Tricalcium silicate grains are smaller in Biodentine
-calcium chloride in the liquid of Biodentine

Question 24

What are the downsides of MTA and Biodentine ?

Answer 24

The pro longed release of CaOH reduce flexural strength

Question 25

What other term is synonymous with pulp stones ?

Answer 25

Dystrophic calcification

Question 26

What tooth structure composition do pulp stones resemble ?

Answer 26

Dentine

Question 27

Where are pulp stones typically found.?

Answer 27

Canal orifice

Question 28

What is a true pulp stone ?

Answer 28

Stones found close to the apex with tubules surrounded by odontoblast like cells

Question 29

What is the difference between a free and attached pulp stone?

Answer 29

Free - surrounded by soft tissues Attached- united to the dentine or secondary dentine is deposited around the stone

Question 30

What are pulp stones ?

Answer 30

Foci of calcification.

Question 31

What is different between pulpal sclerosis and pulp stones ?

Answer 31

Sclerosis is a diffuse process and only occurs in dentinal tubules

Question 32

What is thought to be a cause of pulp stones?

Answer 32

Unknown but related to stimulation of mesenchymal cells by growth factors to undergo odontogensis

Question 33

What are the two shapes pulp stones usually take on?

Answer 33

Smooth laminations - coronal Irregular - radicular pulp

Question 34

How do coronal/smooth pulp stones grow?

Answer 34

Addition of collagen fibres to the surface

Question 35

How do radicular / rough pulp stones form?

Answer 35

Calcification of existing collagen fibre bundles They appear rough because the mineralisation front extends along the coarse fibres

Question 36

What is the cause of pulp stones ?

Answer 36

Unknown but may occur around degenerating blood thrombi / collagen/ degenerating cells

Question 37

What percentage of luxated teeth with calcific metamorphosis has secondary infection?

Answer 37

7% Andreasan

Question 38

Name a paper which refers to calcified mass extraradiculr

Answer 38

Riccuci et al 2005 Harn et al 1998

Question 39

How can extra radicular calculus deposits form?

Answer 39

1. Originated from the sulcus ( more likely if margins alveolar bone not intact) 2. Periapical biofilm at the root surface and calcification may occur due to minerals from GCF or exudate

Question 40

What bacteria are implied in extraradicular biofilm?

Answer 40

-Chromogenic as often it is stained -Actinomyces species (gram positive filamentous) -also found filamentous and cocci bacteria

Question 41

Neuropathic pain mechanism

Answer 41

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

Question 42

What is neuropathic pain?

Answer 42

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