MDS PREP
What type of dental cement is used in cases of rampant caries and unhygienic oral conditions?
1) Zinc polyacrylate
2) Calcium sulfate
3) Zinc oxide-eugenol
4) Calcium hydroxide
Calcium hydroxide is used in cases of rampant caries and unhygienic oral conditions due to its antibacterial and tissue-dissolving properties.
What are the requirements for a good temporary cementing agent?
1) High compressive strength and good thermal conductivity
2) Low compressive strength and good thermal conductivity
3) High compressive strength and low thermal conductivity
4) Low compressive strength and low thermal conductivity
The ideal requirements for temporary cements include promoting the healing process and having a low compressive strength to facilitate removal.
What is the typical mixing time for temporary cementing materials?
1) 1-5 minutes
2) 5-15 minutes
3) 15-30 minutes
4) 1-15 minutes
The text does not specify the exact mixing time for temporary cements, but it states that the mixing time for all three varieties is approximately 1-15 minutes.
What is the typical range of pH for acidic dental cements?
1) pH > 7
2) pH 7-10
3) pH 4-7
4) pH < 4
Acidic dental cements typically have a pH less than 7.
What is the effect of adding a nonionic surfactant to silicone impression materials?
1) Increases hydrophilicity
2) Decreases tear strength
3) Enhances setting time
4) Reduces dimensional accuracy
Adding a nonionic surfactant to silicone impression materials makes the surface more hydrophilic, allowing for better wetting of soft tissues and improved detail capture.
What is the primary advantage of using the frozen slab technique with zinc phosphate cement?
1) It increases the working time.
2) It decreases the setting time.
3) It increases the mechanical properties.
4) It changes the pH of the cement.
The frozen slab technique increases the working time of zinc phosphate cement by allowing more moisture to condense on the cool glass slab.
What is the chemical composition of Giomers?
1) They are made of fluoride-releasing resin with ceramic filler.
2) They are a combination of glass ionomer and composite resin.
3) They contain fluoraluminosilicate glass and polyalkenoic acid.
4) They are composed of a polymethacrylate matrix with silica fillers.
Giomers are hybrid aesthetic restorative materials that employ PRG technology. The chemical composition includes fluoraluminosilicate glass reacted with polyalkenoic acid, which is then included in a silica-filled urethane resin matrix.
During crown cementation, complete filling of crown with cement is not advisable due to :
1) Increased risk of bubble entrapment
2) Increased seating time
3) Increased pressure required for seating crown
4) All of the above
Dental Materials Answer: 4
It is not advisable to fill the crown completely with cement due to following 4 reasons:
1. the time for removal of excess cement elevates.
2. the risk for bubble entrapment increases
3. increased pressure may be needed
4. the time for seating increases