Restorative Dentistry Flashcards
two types of amalgam particles?
spherical
lathe cut
what reacts with mercury when amalgam is mixed?
Ag3Sn
what is the gamma phase associated with?
corrosion, creep and lower strength
modern amalgams have a lower gamma phase because increased concentration of what?
copper
why can amalgam withstand forces?
good compressive strength
how is corrosion reduced?
increased copper
what can corrosion products be beneficial for?
better marginal seal and reduce microleakages
amalgam does not bond chemically so what is necessary?
retention and resistance form to retain the material in the cavity
what restorations are indicated to be amalgam filled?
posteriors
large occlusal forces
where resin not suitable
what does the setting reaction of a resin involve?
polymerisation of the matrix
what is the setting reaction initiated by?
free raducals - intitiate polymerisation
what do light cured materials contain?
camphorquinone
what is added to resins to reduce shrinkage?
methacrylate monomers such as BISGMA
the more filler the more?
stonger and harder wearing the resin is
in composites what is added to ensure the resin and filler work together?
a coupling agent
what is the difference between flowable and traditional composites?
less filler content by 50-70% = less viscous
low wear resistance
indications for composites?
occlusals on posterior teeth proximal lesions cervical lesions incisal edge lesions fissure sealants/PRR
contraindications for composites?
areas of large occlusal loading
tooth cant be isolated
root surface lesions - GI is better option
deep interproximal boxes
what are the essential components of GI?
polyalkenoate acids and ion leachable glass
what are the advantages of RMGICs?
self adhesion to tooth
command cure set
fluordie releasing
disadvantages of RMGICs?
poor fracture strength
water absorption
poor strength in thin sections
stain build up is common
glass ionomer cement indications of use?
liners and bases
ART
root surface caries
