Investment Materials

Question 1

what are investment materials in dentistry?

Answer 1

types of dental material used to make molds/casts of teeth, implants or other dental structures. [creates highly accurate and detailed replicas]

Question 2

what are the types of investment materials?

Answer 2

dental stone or plaster - used in acrylic dentures

gypsum bonded materials - gold casting alloys

phosphate bonded materials - base metals/cast ceramics

silica bonded materials - base metal alloys

Question 3

describe how investment materials used?

Answer 3

for example, a wax pattern is made for a crown or inlay. Then the investment material is poured around the wax pattern and is allowed to set (creating a mould).

Wax is then eliminated (boiling water or burning in oven.

Then the alloy for the crown/inlay is poured into the empty mould where an accurate restoration is made

Question 4

what are the requirements for investment materials?

Answer 4

• they should be able to expand (compensate for cooling shrinkage of alloys inside)
• porous: allows trapped gases to escape
• strong [@room and casting temp]
• smooth surface
• chemically stable
• handling and easy removal from cast
• inexpensive since theyre destroyed after use

Question 5

what are the components of an investment material?

Answer 5

2

• Binder: Gypsum; Phosphate; Silica (binds refractory particles together)
• Refractory Material: Silica (high temperature withstanding)