Acrylic Resin

replaces function of natural teeth goes into patients mouth is seen by other people has to give value for money

dimensionally accurate and stable high softening temperature unaffected by oral fluids thermal expansion low density high thermal conductivity radiopaque non toxic, non-irritant easy and inexpensive to manufacture easy to repair

high youngs modulus high proportional limit high transverse strength high fatigue strength high impact strength high hardness/abrasion resistance

chemical union of two molecules either the same or different to form a larger molecule without the loss of smaller molecule involves molecules with C=C bonds

activation - provide free radicals initiation - break C=C bonds propagation - growing polymer chain termination - of polymerisation

benzoyl peroxide

non-toxic non-irritant unaffected by oral fluids poor mechanical properties good fatigue strength high hardness thermal expansion same as artificial tooth low thermal conductivity low density high softening temperature fairly accurate

benzoyl peroxide but it is activated by tertiary amine in liquid

lower temperature so less thermal conduction and better dimensional accuracy

low molecular weight so poorer mechanical properties more unreacted monomer = irritant and soften denture base water absorption means expansion

3-5%

0.2-0.5%

high impact resistant materials incorporate fibres

high impact heat cure acrylic resin

exceptional flexural strength and fracture toughness allowing it to bend a bit which stops it being brittle

customised impression tray material and for repair of fractured dentures

water absorption so swelling and softening

nylons vinyl polymers polycarbonates

softening in use

distortion in use