Casting procedure

Function of a 'Ring liner'

• To create channel for elimination of wax during burnout

• Allows mold expansion(cushion effect)

• Reservoir of molten metal compensating for alloy shrinkage

• None of the above

Sprue direction should ideally be

• 45° to proximal area

• 90° to proximal area

• 45° to occlusal area

• 90° to occlusal area

Setting expansion of casting investment:

• 0.8 - 1%

• 0.1 - 0.5%

• 1 - 2%

• 2 - 4%

Which part of the flame is used for fusion of casting alloy

• Mixing zone

• Communion zone

• Reducing zone

• Oxidizing zone

Which of the following are used for removing the sprue from casting

• Joe Dandy discs

• Moore discs

• Meatless stone

• Busch silent stone

Sprue length with respect to end of the ring

• Within 5mm

• More than 5mm

• Within 6mm

• More than 6mm

Ideally, a casting should fit with in:

• 20microns

• 10microns

• 50microns

• 25 - 40microns

Temperature for burnout in hygroscopic and thermal expansion technique are

• 600C and 800C

• 500C and 700C

• 700C and 400C

• 400C and 600C

Solution used for 'Pickling'

• 60% HCL

• 50% HCL

• 40% HCL

• 70% HCL

Which of the ring liner has 'Cariogenic potential'

• Asbestos

• Fibrous ceramic aluminous silicate

• Cellulose

• Ceramic-cellulose combination