This fact is from Dental Casting Alloys & Investment in Dental Materials. It is a commonly tested concept in NEET MDS examinations. Understanding this fact is crucial for answering MCQs correctly.
Type I gold alloy = inlays soft
Type II = inlays onlays medium
Type III = crowns bridges hard
Type IV = partial denture frameworks extra hard
Ni-Cr = most common base metal alloy = beryllium concern
Gypsum bonded investment = gold casting = low melting
Phosphate bonded investment = base metal = high melting
Silica bonded = highest expansion.