DM 1 - Principles of fibre reinforcement

Question 1

What is fibre reinforced composite (FRC)?

Answer 1

• synthetic material (polymer + fibres)
• the fibres would be supporting the composite

Question 2

What considerations must be made with FRC and the oral environment?

Answer 2

• pathogen microbes
• humidity
• mechanical load: direction of biting force
• appearance

Question 3

In terms of the oral micrbiome, what should FRCs be able to withstand?

Answer 3

the acid attacks and change in pH caused by bacteria

Question 4

What 3 main fibre types can be used in FRC?

Answer 4

• carbon graphite fibres: not in use due to aesthetic reasons
• aramid fibres: not in use due to cosmetic problems
• glass fibres: the type mostly used in dentistry

Question 5

What are the subdivisons of glass fibres?

Answer 5

A-, C-, D-, E-, E-CR-, R-, S- glasses

Question 6

What types of glass fibres are mostly used in dentistry?

Answer 6

E-glasses, R-glasses and S-glasses

Question 7

What could the surface of glass fibres be enriched with?

Answer 7

boron and calcium

Question 8

How is E-glass (alkali-free glass) modified?

Answer 8

modified adding boron oxide and reducing CaO to made it more resistant to acid attacks

Question 9

What is an important feature that glass fibres should have?

Answer 9

should be radiopaque

Question 10

What negative effect may the addition of fillers to glass fibres cause?

Answer 10

could compromise the strength of the material

Question 11

What are te 2 types of polymers that can be in the matrix of a FRC?

Answer 11

linear (thermoplastic) and cross-linked (thermoset)