waxes Flashcards
what state are waxes usually at room temperature?
solid
waxes are thermoplastic, what does this mean?
that they become mouldable on heating and harden on cooling and can repeat this process
what is the primary use of waxes in dentistry?
to form patterns of appliances before casting
what does the wax pattern of a stone model determine?
the shape and size of the resulting appliance
what is wax replaced by in the making of the appliance and what is this replacement technique called?
either a polymer or an alloy by the lost wax technique
most appliances are made by indirect techniques, how may inlays be made?
by a direct wax pattern technique in which the play wax is adapted and shaped in the prepared cavity in the mouth
why must waxes have precisely controlled properties?
to ensure well fitting restorations or appliances
what is carding wax used for and why can it not be used to make wax patterns of appliances?
for attacking artificial teeth to display sheets. because they have less rigorous property requirements.
what is boxing in wax used for?
to box in impressions prior to making a gypsum model
what is sticky wax used for?
to join two parts of an appliance temporarily e.g. during soldering to facilitate union
what are the 3 requirements of wax pattern materials?
wax pattern must conforms to the exact shape, size. and contour of the appliance that is to be constructed.
no dimensional change should take place in the wax pattern once it has been formed.
after formation of the casting mould, it should be possible to remove the wax by boiling out or burning without leaving a residue
what does the ability of a wax to record detail depend on?
the flow of the material at the moulding temperature
what kind of structure do waxes have?
crystalline structure
what kind of origins may the major components of waxes have?
animal e.g. beeswax, vegetable e.g. carnauba wax and mineral e.g. paraffin wax
what dictates the properties of a wax?
the blend of components
