composite resins Flashcards
advantages of composite resins
aesthetic
tough durable and insoluble in the oral environment
low failure rates reported
challenges of composite resins
adhesion to the tooth tissue
technique sensitivity
stimuli of the teeth
physical e.g. mechanical forces trauma chemical - e.g. acids
what do restorations do
restore the integrity of the tooth structure
ideal direct aesthetic restorative material properties
1) safe for dental team and patient
2) aesthetic
3) durable, chemically stable and tasteless
4) poor conductor of heat
5) minimal tooth preparation
- keep as much tooth as possible
6) easy to use
7) cost effective
Properties of typical composite resin
1) Safe for dental team/patient
2) aesthetic
3) durable, chemically stable and tasteless
- fully polymerised materials are tough, durable and tasteless
4) Poor conductor of heat
- have a co efficient of thermal expansion close to tooth tissue
5) minimal tooth prep
- don’t need a large undercut
disadvantages of resin
technique sensitive
not generally cheap but highly efficient
what are materials generally classified as
metals
ceramics
glasses
polymers
composite definition
where two of more materials are combined to produce improved properties
composite ‘rles’
component materials are largely unchanged by the presence of others
- there must be some form of interfacial bonding between the components
how do composites work
different components bring their different properties to the final composite material
dental composites composition main elemtns
matrix componnet
filler
photo initiator
inhibitor
what is the matrix component in composites
methacrylate resin monomers
what is the filler in compsoites
silica powder
what is an example of a photo initiator
camphorquinone
what does an inhibitor do
extends shelf life
what are acryaltes
made from vinyl monomers
small molecules with C=C bonds
acrylates are a family of vinyl polymers
what are methacyrlates
have an extra methyl group attached to th alpha carbon
what are filler components typically
amporphous silica, glass or quartz powders (irrg shapes and sizes)
ways to set dental composties
chemical cure
- two pastes are mixed (activator with free radical initiator)
light activiation
- photo initiator
camphorquinone is typical
initiated by exposure to appropriate lamp
properties of composites
tough and relatively wear resistant
durable and insoulble
aesthetic
possible to achieve goo bond strength with tooth tissue
safe and biocompatible if handled correctly
is composite hydrophilic or hydrophobic
hydrophobic
- needs bonding system to adhere to hydrophilic tooth tissue due to methacrylate moomers
