fibre reinforced composite Flashcards
(31 cards)
When were fibre reinforced composites first used?
1960s
Research is ongoing into additional uses and longevity of FRC.
what is the composition of FRC
glass fibres and matrix composed of a polymer
What are the most commonly used glass fibres in FRC?
- E-glasses
- R-glasses
- S-glasses
How can E-glass fibres be modified for better acid resistance?
By adding boron and reducing calcium
What does anisotropicity refer to in the context of FRC?
Fibres are positioned based on the direction and power of the forces exerted on them
What are the types of polymers used in the matrix of FRC?
- Linear polymer - PMMA
- Cross linked polymer
- Dental resin systems
name 3 types of dental resin systems in the matrix of FRC
bis-GMA, TEGDMA, UDMA
What is a semi-IPN in the context of FRC?
A semi interpenetrating polymer network combining a linear polymer with a cross-linked polymer
What are the advantages of using a semi-IPN?
- Better handling
- Improved bonding
- Increased toughness
What factors influence the impregnation of fibres in FRC?
- Surface wetting properties of the fibres
- Distance between fibres
- Viscosity of the resin material
What is the pre-impregnation method in FRC?
PMMA is dissolved in a solvent that evaporates, leaving the fibres embedded in PMMA
what are fibres pretreated with to improve surface wetting and chemical adhesion
silanes
Direction of the fibres affects the ? properties of the FRC
mechanical
explain Continuous unidirectional fibres
one single direction
explain continuous bidirectional fibres
2 directions
explain continuous random oriented
random direction
explain woven fabric/discontinuous random orientated
interlaced fibres in a specific pattern
when are continuous unidirectional fibres used in FRC?
for high forces in a single axis
when are continuous bidirectional fibres used in FRC?
when flexural and tensile strength are required - increase load bearing and resistance to fracture
when are continuous random orientated fibres used in FRC
provisional restorations as cost effective short term solution
What factors affect the success of FRC? 6
- Fiber alignment
- Restoration design
- Volume of fiber fraction
- Fiber length
- Interfacial bonding
- Curing and polymerization
How does the volume of fiber fraction affect FRC?
- More fibres increase strength and stiffness
- Too many fibres compromise flow and placement
What is the impact of fiber length on FRC?
- Longer fibres transfer stresses more efficiently but decrease mechanical properties
- Shorter fibres allow easier handling
What are the advantages of FRC? 5
- Easy manipulation and repair
- Improved flexural, fatigue, elastic modulus, and bond strength
- Metal free
- Low cost and aesthetic
- Minimal lab work required
