NEET MDS Shorts
92220
Dental Materials
The specification controls the qualities of dental amalgam by listing requirements for creep, compressive strength, and dimensional change.
14423
Dental Materials
Water-based cements include zinc polycarboxylate and calcium sulfate.
19186
Dental Materials
The specification requires that amalgam neither contract nor expand more than 20 µm/cm.
87020
Dental Materials
The light source is crucial in the photopolymerization process as it activates the photosensitizer, usually camphorquinone, which in turn generates free radicals that initiate the polymerization of the resin.
11561
Dental Materials
Light-cured resins generally have less shrinkage and are more aesthetically pleasing due to their ability to be polymerized to a higher degree. They also offer improved bond strength compared to chemically cured resins.
23582
Dental Materials
Using a lower concentration of phosphoric acid, such as 15% to 30%, can create deeper tags on the enamel surface, potentially leading to a stronger mechanical bond.
55873
Dental MaterialsFerrite and austenite are soft and ductile
30407
Dental Materials
Heating a gypsum cast to a temperature above 90°C will remove water of
crystallization and strengthen it. This process is called "burning out" the
gypsum, and it is used to remove the remaining moisture and improve the cast's
stability and accuracy. Gypsum casts are made by mixing plaster of Paris (calcium sulfate hemihydrate)
with water. When the material sets, it forms calcium sulfate dihydrate crystals
with water molecules trapped within the crystal lattice, known as water of
crystallization. Heating the cast above 90°C causes the water of crystallization
to be released, which results in the cast becoming stronger and more rigid. This
process does not cause the cast to expand but rather to shrink slightly as the
water is removed. Excess gauging water is typically removed during the initial
setting process.
11917
Dental Materials
The primary concern is the potential for pulpal toxicity due to the diffusion of eugenol.
23136
Dental Materials
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