dental cements Flashcards
classification of dental cements
comparitively low strength harden to act as liner base varnishes filling matrerials they are non metallic based on application type 1 luting type 2 restorations type 3 cavity liners and bases on the bases of materials acid base reaction cements polymerizing materials cyanoacrylate dimethacrylate other materials calcium hydroxide gutta percha varnishes
glass ionomer cement part 1
type 1 for luting and bonding agent
for inlays, crown,bridges
orthodontics bracket
for this powder liquid ratio
1;5;1
type 2 restoration 3;1 powder ratio
type 3liner and bases :
type 4 liner bases
setting occurs by calcium reacting with polyacrylic acid
along with aluminium sodium ions reacting with fluoride
to form sodium fluoride
the initial set is due to cross linking of calcium and aluminium
manipulation
cool dry glass slab two increment division first increment rapidly incorporated for milky consistency then next remainder powder added for gel like consistency folding method mixing is done
gic extremely sensitive to water and air matrix is applied into the cavity
also protected by light cure resin and varnish
properties of gic
tooth coloured restorative material
mechanical properties
hardness 49khn
compressive strength 150 mpa
tensile strength for luting 6.6mpa and 6.2 for restoration
coefficient of thermal expansion : 11 * 10 to the power -6 and tat of enamel 11.4* 10 to te power -6
moudulus of elasticity 7.3 gpa
anticariogenic property atrribted to fluoride ions aiding remineralization and formation of acid resistant fluroappetite
radiopacity small atomic no of ions les adsorbtion of x rays thus strintium adde with calcium and does no invlove with the setting reaction
chemical bonding to dentin with a bond strentgh of 3-5 mpa
diadvantage hardness is leaas as compared to composite
extremely sentitive to air and water while setting
calcium hydroxide
low strength used for pulp capping and as bae for composite restorations
tenisle compressive strengths , 1 and 10 to 27 rrespectively
modulus of elaticisty 0.37gpa
thermal propeties good due to several layesr
aids in the formation of secondary or reparative dentine dueto high alkalinity and anti bacterial properties
zinc oxide eugenol cement
classufication type 1 temporary cementation setting type and non setting type type 2 permamnent cementation type 3 temporary filing material type 4 cavity liners mechanical prperties tensile strentgh upto 5.3 compressive 5- 55 modulus upto 5.4 gpa cote 34 10 to the powr minus 6 thermal insulation highest solubillity film thickness 25mu m bacteriostatic and obduntant property
purpose of cavity liners and bases
pulp healing treat dentinal hypersenistivity proyect pulp prevent perlocation of oral fluids antibacterial
