771. During the casting of noble metal alloys, the mold should be held at the burn out temperature for atleast
A. 15 minutes
B. 60 minutes
C. 3 hours
D. 6 hours

772. In general the hygroscopic expansion of gypsum investments will be higher if they contain
A. coarser silica particles and alpha hemihydrate
B. liner silica particles and beta hemi hydrate
C. coarser silica particles and beta hemihydrates
D. finer silica particles and alpha hemihydrate

773. The cement capable of forming a chemical bond with tooth structure is
A.reinforced zinc oxide eugenol cement.
B. silicophosphate cement
C. polycarboxylate cement
D. composite resin cement

774. Quartz in dental porcelain acts as a
A. binder
B. frit
C. opacifier
D. Strengthener

775. The principal strengthening phaseofCerestore, an injection molded ceramic material, are
A. aluminium oxide and silicon oxide
B. magnesium silicate and beta-aluminium
C. alpha-alumina and magnesium aluminate Spinel
D. none of the above

776. Which of the following resins may be classified as thermosetting?
A. Polystyrenes
B. Vinyl resins
C. Epoxy resins
D. Impression compound
E. None of the above

777. A dental appliance containing metals or soft lining materials, should not be cleaned with denturecleansers containing
A. sodium perborate
B. soap
C. hypochlorites
D. salt
E. none of the above

778. A dental restoration may be tarnished because of
A. deposition of calculus
B. surface discoloration
C. formation of oxides or sulfides
D. deposition of pigment producing bacteria
E. all of the above

779. An agar hydrocolloid impression should never be removed from the mouth by a teasing or weavingmethodbecause this can result in distortion of the impression.
A. Both the statement and reason are true
B. The statement is true but the reason is falseFCPS Part 1 DentistryRefrence: Vijay Pratab Singh Mcqs in Dentistry
C. The statement is false but the reason is true
D. Both the statement and reason are false

780. The curing rate of most of the elastomeric impression materials can be accelerated by
A. mixing on a chilled, dry glass slab
B. the addition of thinners
C. the addition of a drop of water during mixing
D. mixing at a low room temperature
E. none of the above