crown and bridge

curve of spree - concave curve on mand convex on max

curve of wilson - curved line from buccal to lingual, lingual cusps are shorter than buccal cups

height of contour - 1/3 from gingiva

extention of HOC - 0.5mm past thr CEJ except the lingual mand posterior which is 0.75 - 1.0 mm

Inlay wax - thermal expansion = largest coefficant of thermal expansion, flow = increases as melting range of wax is approched, strain relase = causes stress which can lead to distoration and lack of fit on the tooth

molding wax - low shrinkage, hard non elastic, high surface tension, for carving properties

cervical wax - low shrinkage, stable, good carving properties, burns without residue, hard

whats matrix - it records the surface of a tooth from all angles and is made out of silicon

matrix has to be mixed with even amount of base and calayst

matriz should extend to 1.5 of a tooth on each side

laws of casting- there are 17 laws of casting to help with porosity, miscast, short margines, tears, nlown investment ring, nodules, voids, distoration

law 1 -attach sprue to the thickest part of wax

law 2 -margins shuold face down and to the right

law 3 - position pattern in cold zone

law 4 - resevior must have a sufficient molten alloy

law 5 - dony use runner bar

law 6 -eliminate turbulance

law 7 - select proprt casting ring

law 8 - reduce surface tension by spraying picosillk

law 9 -measure appropiate water powder ratio depending on metal

law 10 -use vavuum mixer

law 11 -allow investment to sey benchset

law 12 - select appropiate time and temptuature dependting on the metal and investment

law 13- melt allow with heat

law 14- use reducing zone of the flame to melt alloy

law 15- make sure machine was winded up properly

law 16- do not quench after casting let invesment sit benchset

To increase expansion - increse special liquid, mix with warm water, use softer wax, increaase spatula time

to decrease expansion -decrease special liquid, mix with cooler water, use harder wa, decrease spatula time

whats the thickness of porceline over metal - 1.0 -2.0 mm

whats the thinwst wa an be before casting - 5.0 mm

max thinest of metal - 0.3

whats the max thickness of metal - doesnt matter

whats the base alloy burnout temp - 1550 * F

final burnout time depends on what - # of rings

how to find out how much metal is needed - weight of pattern + sprue x specific gravity of metal = weight of metal needed

what is the base alloy we use in school called - D.SIGN 30

what is the density of the base alloy - 7.8

what is the burn out range of the base alloy - 1550F 800-850C

whats the melting range of the base alloy - 1145-1165C

whats the casting rang of the base alloy - 1240 - 1350C

Red wax is used for the durability for the set up