Cements and Their Uses

Question 1

what are the types of cements

Answer 1

-zinc phosphate
-zinc oxide eugenol
- zinc polycarboxylate
-glass ionomer
- resin modified glass ionomer
- provisional cements

Question 2

cement will not perform to its optimal level clinically without an ___

Answer 2

adequate preparation that includes good resistance and retention form

Question 3

what are the different properties of cements

Answer 3

-biocompatibility
-retention
- mechanical properties
- marginal seal
- low film thickness
-ease of use
-radiopacity
-esthetics

Question 4

what are the mechanical properties of cements

Answer 4

withstand occlusal forces, high tensile strength

Question 5

what is the gold standards of cements

Answer 5

zinc phosphate

Question 6

what are the advantages and disadvantages to zinc phosphate

Answer 6

-advantages: thin film thickness and proven reliability, low solubility which resists breakdown in the mouth, low thermo conductivity, provides less sensitivity to hot and cold, long shelf life
- disadvantages: initial low pH which can lead to pulpal irritation, no chemical adhesion/bond, no antibacterial properties, poor esthetics, long setting time of 2.5-8 minutes, exothermic

Question 7

describe type 1 zinc oxide eugenol

Answer 7

-less strong and is used for temporary restorations and for temporary cementation
-temp-bond

Question 8

describe type 2 zinc oxide eugenol

Answer 8

-reinforced and is stronger
-referred to as an intermediate restorative
-can last for 6-12 months in the mouth
-used for a tooth that cannot be restored immediately (IRM)

Question 9

what are benefits of zinc oxide eugenol

Answer 9

-neutral pH
- has a sedative or soothing effect on the dental pulp
- protective or insulating base of liner is not required

Question 10

what is zinc oxide eugenol not used under and why

Answer 10

-not used under composite or acrylic restorations because it is incompatible with these materials and retards their setting process

Question 11

what do the type and intended use of zinc oxide eugenol determine

Answer 11

whether the powder is incorporated into the liquid in increments or all at once

Question 12

what is the mixing time for zinc oxide eugenol

Answer 12

30-60 seconds

Question 13

what is the setting time for zinc oxide eugenol

Answer 13

3-5 minutes

Question 14

what is the first cementing system to obtain an adhesive agent that bonds to enamel and dentin

Answer 14

zinc polycarboxylate

Question 15

what are the characteristics of zinc polycarboxylate

Answer 15

-antibacterial action
- shorter working time of 2-5 minutes
- needs to be mixed quickly 30-40 seconds

Question 16

describe the characteristics of polycarboxylate

Answer 16

• powder incorporated in large quantities
• it is not as fragile as zinc phosphate
• can have poor marginal sealing due to film thickness
  -sometimes doesnt support occlusal stress as well as newer cements
• will bond to most allows but not to gold
• due to its potential for plastic deformation, it is much more difficult to remove excess cement
• although bonds well to enamel/dentin its use has lessened over the years

Question 17

what is another name for glass ionomer

Answer 17

acid base cement

Question 18

what is part of the success of glass ionomer cements

Answer 18

their performance is good even if they have not been properly mixed

Question 19

what are the characteristics of glass ionomer

Answer 19

-very thin film thickness
-extremely moisture tolerant but fairly soluble
-fluoride release that can be sustained for long periods of time
-protects the tooth/margins from further tooth decay
- radiopaque

Question 20

describe fluoride release in glass ionomer

Answer 20

initial rapid release followed by a sustained lower level diffusion release

Question 21

when is fluoride released by a glass ionomers

Answer 21

in acidic conditions and will increase the pH to buffer

Question 22

what are the uses for glass ionomer

Answer 22

liner, luting agent, build up material, contain silver particles for strength

Question 23

what are the characteristics of resin modified glass ionomers

Answer 23

-added hydrophillic methyacrylate monomers
-acid base cement
-all the same benefits/advantages of glass ionomer cements
- disadvantages: low early strength and moisture sensitivity during setting

Question 24

how long does it take for resin modified glass ionomers to fully set

Answer 24

24 hours

Question 25

how do working times affect film thickness

Answer 25

longer working times allow more flow and will aid in seating the restoration

Question 26

what happens to the film thickness once the material begins to set

Answer 26

the viscosity rises rapidly and flow becomes impossible

Question 27

how long do you have to mix and place the cement

Answer 27

2-2.5 minutes

Question 28

what is the role of temporary cement

Answer 28

keeping the temporary restoration on the tooth while the patient is waiting for the final restoration to return from the lab

Question 29

what qualities must the temporary cement provide

Answer 29

-needs to be easily removed from prepared tooth without harming periodontium, tooth preparation or pulp
- must have eugenol

Question 30

what can eugenol have a negative effect on

Answer 30

acrylic resins and composite resin cements

Question 31

what benefit does eugenol provide in temporary cements

Answer 31

antibacterial effect

Question 32

what are the temporary cement names

Answer 32

-temp bond
- ultra temp
- relyx temp

Question 33

what qualities do you think about when selecting a temporary cement

Answer 33

• how long
• how retentive
  -what will permanent cement be
  -working in esthetic zone

Question 34

what is the gold standard of cements

Answer 34

zinc phosphate