Intermediary Materials And Cements

Question 1

What are dental cements used for?

Answer 1

To lute (glue/cement) inlays, crowns bridges and other restorations in place

Question 2

Ideal properties of a dental cement

Answer 2

Strong/hard
Protect pulp
Insoluble in saliva
Stable
Adhesive
Non-porous
Biocompatible 
Easy to manipulate 
Not affected by thermal changes

Question 3

Film thickness

Answer 3

Dental cement should have a film thickness of .25 micrometers

Question 4

Viscosity

Answer 4

Resistance of liquid to flow

Question 5

Setting time

Answer 5

Time required for a material to polymerize or harden

Question 6

Strength

Answer 6

Ability of a prosthesis to resist induced strength without fracture or permanent deformation

Question 7

Solubility

Answer 7

The amount of a substance that will dissolve in a given amount of another substance

Question 8

Other terms for dental cements

Answer 8

Limiting agents
Base
Filling material
Temporary restoration 
Intermediate restoration 
Periodontal pack
Temporary cement

Question 9

Three basic categories of dental cements

Answer 9

Water based
Resin based
Oil based

Question 10

Water based cements

Answer 10

Rely on acid base setting reaction. Do not bond well. Some release fluoride and have low film thickness

Ex. Glass ionomer cements, zinc phosphate

Question 11

Resin based cements

Answer 11

High bond strength. Many use adhesives. Some have monomers or use primers so that they will bond to dental alloys and ceramics

Ex. Resin modified ionomer cements, copomers)

Question 12

Oil based cements

Answer 12

Used for luting restorations. Most contain eugenol but there are some oil free cements. These are thicker and have lower mechanical properties

Ex. Zinc oxide eugenol, non-eugenol cements

Question 13

What forms do glass ionomer cements come in? Are they water or resin-based?

Answer 13

Can be both water-based and resin-based

Come as a powder and liquid and even as a single dosed capsule

Question 14

What kind of sudden reaction do water-based cements have? How do they bond, how are they mixed and what is the working time?

Answer 14

Acid based reaction
Bind chemically to enamel and dentin
Can be mixed on a glass slab or paper pad
Working time is approximately 2 min

Question 15

How are resin modified glass ionomer cements cured, what form are they available in?

Answer 15

They are both self cure and light cured

Available in powder and liquid, paste and encapsulated

Question 16

What are resin modified glass ionomer cements used for?

Answer 16

Permanent cementation, ceramic metal crowns, bridges, metal in leas, Onley‘s can also be used for luting

Material of choice for cementing permanent crowns. They are the strongest and least soluble

Question 17

What is zinc phosphate used for?

Answer 17

“Traditional” crown and bridge cement

Question 18

How is zinc phosphate supplied? What type of reaction results from the mixing process?

Answer 18

Supplied as a liquid and powder which begins the setting reaction when you start mixing.

Results in an exothermic reaction because of the acid in the mixture. Must be mixed on a cool glass slab. Mix slowly

Question 19

What is a major component of Resin-based/composite cements? What are they used for?

Answer 19

Major component is silica or glass.

Used for crowns, bridges, restorations, bonding brackets

Question 20

Characteristics of resin based cements

Answer 20

Have superior bonding strength
Manipulation is critical to performance
Tooth surface must be edged with acid
Tooth must be cleaned and isolated
Can be used for veneers

Question 21

What are copomers?

Answer 21

Poly acid modified composites

Used for cast alloy crowns, bridges, ceramic and metal crowns and bridges, gold inlays, onlays and veneers

Question 22

What are the two oil based cements?

Answer 22

Zinc oxide eugenol and non-eugenol cements

Question 23

What are oil based cement used for?

Answer 23

Temporary restorations, soft tissue pack, root canal sealer‘s

Non- eugenol can be used if a patient is sensitive

Question 24

What is the mixing process for oil based cements?

Answer 24

2 paste

disperse equal length of each onto a paper pad. Mix until uniform in color

Question 25

What are the four types of oil based cements? What is the range of setting time?

Answer 25

Type I- temporary cement
Type II- permanent cement
Type III- filling materials and bases
Type IV- cavity liners

Setting time ranges from 15 minutes to 12 hours

Question 26

What is a common type of cavity varnish?

Answer 26

Copalite

Question 27

What do cavity varnishes do?

Answer 27

Act as a barrier against irritants
Reduces oral fluid into Dentin
Do not bond to tooth
Not used with composite restorations
Many are used with zinc phosphate cement

Question 28

What is one type of dental bonding agent? What does it do?

Answer 28

Gluma primer bonding agent is being used as a varnish

Helps bond the amalgam with the tooth structure

Question 29

What are cavity liners/bases used for?

Answer 29

To create a secondary Dentin when applied to pulp exposures

High strength bases provide thermal protection for pulp

Question 30

What is the primary cause of failure?

Answer 30

Washout. Which means cement loss, which means leakage

Question 31

Why does leakage occur?

Answer 31

Secondary decay