Resin Composites Presentations Flashcards
What are the methods to overcome stress in bulk fills?
- Include the polymerisation modulator
- Includes 2 monomers one which is a high molecular weight aromatic dimethacrylate (AUDMA) which decreases number of reactive groups in resin (groups which shrink)
What works in combination with AUDMA to decrease shrinkage?
A class of compounds called addition-fragmentation monomers (AFM) works in combination with AUDMA to decrease the shrinkage stress
How does AUDMA (methacrylates) decrease stress?
React into developing polymer by forming cross links between adjacent polymer chains.
When stressed during polymerisation these molecules may break or fragment so providing a means for relaxation of the developing polymer network and so stress is relieved
Methyacylates relive stress in the polymer but are the physical properties stay?
Yes, physical properties of the polymer maintain
What are 3 strategies to allow light penetration?
Lower filler content and increased filler particle size
Modify resin to increase its translucency
Use a different initiator system
What are the features of a filler? (Composition)
Non-aggregated silica and zirconia filler
Nanohybrid
What is the filler loading?
Filler loads c77% by weight
Why can bulk filled restorative material be used for the entire restoration (compared to previous)?
Increased viscosity, increased filler, good loading, good wearing
What are the advantages of bulk fill materials?
Reduction in stress within remaining tooth tissue
Decreased cusps flexure
What are the disadvantages of bulk filler compared to conventional resin composite?
Not as strong in comparison
Decreased hardness
Decreased wear resistance
*some concerns about water sorption
When would you use bulk fills?
Direct posterior restorations
Lining material under direct restorations
Indirect restorations
Restorations on deciduous teeth
Fissure sealing
Repair or defects in ceramic restorations and temporaries
How would you cure fill-up bulk fill? How deep can it be filled?
Dual cured, can be cured up to 10mm
What type of resin based composite would you use to provide the best aesthetic outcome?
Layering resin
What technique do you need to use with layering based composites?
Matrix technique
Why do you need to use a matrix technique when using layering technique?
Needs to be placed in the correct amount and place
