**Bases and Liners

Question 1

What are the two main purposed of placing a base/liner?

Answer 1

-to protect the pulp and/or aid it it’s recovery
-to raise the level of the floor of the prep to the ideal height for the restoration

Question 2

Are liners thick or thin layers of material?

Answer 2

thin

Question 3

Are bases thick or thin layers of material?

Answer 3

thick

Question 4

List the benefits of placing a liner under a restoration

Answer 4

-to seal off the dentinal tubules
-prevent irritation to the pulp
-to prevent marginal leakage

Question 5

Why can sealers/liners not provide thermal insulation or strength to the pulp?

Answer 5

because they are thin layers

Question 6

Why is a cavity varnish contraindicated under a composite restoration?

Answer 6

the monomer in the composite resin will react with and dissolve the solvent in the cavity varnish

Question 7

If an insulating base is being placed under an amalgam restoration, should the cavity varnish be placed before or after the placement of that base?

Answer 7

after

Question 8

Why should the bottle of the cavity varnish immediately be recapped after each use?

Answer 8

to prevent evaporation

Question 9

Is a reinforcer considered a base or a liner?

Answer 9

base

Question 10

What is the purpose of placing a reinforcer?

Answer 10

to protect the pulp from the pressures of condensing amalgam

Question 11

Are insulators considered bases or liners?

Answer 11

bases

Question 12

What is the purpose of placing an insulator?

Answer 12

to insulate the pulp against thermal irritation

Question 13

What are the two main characteristics that must be considered for a material to be considered an insulating base?

Answer 13

-must be a poor thermal conductor itself
-must be able to withstand the condensing pressure during the placement of the restoration

Question 14

What does “ZOE” stand for?

Answer 14

zinc oxide-eugenol

Question 15

What is the liquid ingredient in ZOE?

Answer 15

eugenol/oil of cloves

Question 16

Why can ZOE not be placed as a base under composite restorations?

Answer 16

the eugenol in ZOE will negatively interact with the setting of the composite resin

Question 17

Why must a cavity varnish or a non-irritating liner be placed under a zinc phosphate cement base?

Answer 17

because of the phosphoric acid in the zinc phosphate, it can be irritating to the pulp

Question 18

When is it most beneficial to place an obtundant under a restoration?

Answer 18

when the tooth has undergone trauma because obtundants are used to be soothing to the pulp

Question 19

What type of prep are pulp stimulators must commonly placed?

Answer 19

deep cavity preps/near pulp exposures

Question 20

What does it mean that pulp stimulators are mildly irritating in a beneficial way to the pulp?

Answer 20

because it will help encourage the tooth to produce reparative dentin to protect the pulp

Question 21

What are the two most common pulp stimulators?

Answer 21

-calcium hydroxide (dycal)
-glass ionomer

Question 22

How deep is a minimal depth prep?

Answer 22

through the enamel and 1mm into the dentin

Question 23

What depth prep typically does not require a base or liner?

Answer 23

minimal depth

Question 24

How deep is a moderate depth prep?

Answer 24

1mm into the dentin, but further than at least 0.5mm from the pulp

Question 25

How deep is a near pulp exposure prep?

Answer 25

less than 0.5mm from the pulp

Question 26

What area of the prep should you place a pulp stimulator in a moderate depth prep?

Answer 26

at the deepest area of the prep