Bonding and Cementation

Question 1

List 4 types of conventional cements

Answer 1

1. Zinc oxide eugenol (eg temp bond)
2. Zinc phosphate
3. Zinc polycarboxylate
4. Glass ionomer

Question 2

Example of a resin based cement

Answer 2

Panavia

Question 4

What is adhesion?

Answer 4

A molecular or atomic attraction between two contacting surfaces promoted by interfacial force of attraction between molecules or atoms of two different species

Question 5

List 5 factors which affect adhesion

Answer 5

• Wetting
• Contact angle
• Surface energy
• Surface contamination
• Water

Question 6

Wettability of a bond is influenced by (2)

Answer 6

• Cleaniness of the surface
• Surface energy

Question 7

List 4 advantages of adhesive bonding

Answer 7

1. Provide retention
2. Increase strength
3. Reduce microleakage
4. Aesthetic

Question 8

Why are primers needed?

Answer 8

They maintain the expanded collagen network, whilst removing residual water to allow for infiltration of the hydrophobic adhesive monomer

Question 9

What primer is often used in bond

Answer 9

Hema-hydroxymethyl-methacrylate

It is both hydrophilic and hydrophobic so good intermediate.

Question 10

What is bond made with usually?

Answer 10

Bis-GMA

Question 11

3 primary goals of adhesive:

Answer 11

1. Fill the interfibriallar space of the collagen network
2. Provide a hybrid layer and resin tags
3. Provide micromechanical retention once polymerized

Question 12

What ingredient in bond prevents collagen collapse

Answer 12

HEMA.

It is the primer.

Question 13

What ingredient in bond chemically bonds to the primer and the composite through MMA bonds

Answer 13

Bis-GMA

Question 14

List 4 oral environmental factors that influence adhesion to tooth tissue

Answer 14

1. Moisture
2. Physical stress and chewing
3. Changes in temp
4. Changes in pH

Question 15

List 2 prepared cavity related factor which affect adhesion to tooth tissue

Answer 15

1. Surface contamination
2. Saliva contamination
3. Dentine quality

Question 16

What is the ‘hybrid layer’

Answer 16

A mechanical interface between the tooth and adhesive

Question 17

What are resin tags?

Answer 17

Adhesive resin which has locked into the microporosities of etched enamel and intertubular dentine, providing micromechanical bonding

Question 18

List 6 requirements of a successful dentine bonding system

Answer 18

1. Removal or dissolution of smear layer
2. Maintenance of dentine collagen matrix
3. Good wetting
4. Efficient monomer diffusion and penetration
5. Polymerisation with tooth structure
6. Copolymerisation with composite resin matrix-

Question 19

What is a cement

Answer 19

Substance that hardens from a viscous state to a solid union between two surfaces.

Question 20

For luting applications, the maximum allowable film thickness is:

Answer 20

24 um

Question 21

List 10 requirements of an ideal luting cement

Answer 21

1. Biocompatible
2. Good marginal seal
3. Ressitant to saliva dissolution
4. Physical properties as required
5. Adequate working time and setting time
6. Good aesthetics
7. Good thermal and chemical resistance
8. Radiopacity
9. Low film thickness
10. Retention - enhanced by adhesive bond between cement and restorative material

Question 22

Whilst resin cements have greater strength and lower solubility than other cements such as zinc phosphate, polycarboxylate, the trade of is:

Answer 22

More technique sensitive

Question 23

Why should light cure cements rather than dual cure be used for aesthetic restorations

Answer 23

More colour stable

Question 24

Why might you want to use GI or RMGIC for cementing zirconia and metal restos compared with resin cement

Answer 24

Less post op sensitivity

Question 25

What type of luting cement has the best compressive strength

Answer 25

Resin