274+ quick-fire dental facts • tap a card to flip
ORMOCER stands for Organically Modified Ceramic. These materials are advanced filling options in dentistry with a unique matrix technology and filler particles that result in high biocompatibility and aesthetics.
What does ORMOCER stand for in the context of dental filling materials?
1) Organically Modified Resin-ceramic Opportunistic
2) Organically Modified Resin-ceramic Material
3) Organically Modified Ceramic
4) Optimized Resin-ceramic Matrix
Fabrication of ceramics and metals like titanium that are difficult to cast, is done by CAD-CAM process and copy milling.
Apart from composites and ceramics, another material that could be copy milled easily and inexpensively is:
1) Molybdenum
2) Germanium
3) Titanium
4) Chromium
The compressive strength of hardened zinc oxide eugenol (ZnOE) impression paste is generally about 7 MPa, indicating its ability to withstand compressive forces without deformation or failure.
What is the typical compressive strength of hardened ZnOE impression paste?
1) 0.4-0.7 MPa
2) 7 MPa
3) 245 MPa
4) 32 MPa
A higher degree of polymerization in resins generally correlates with greater strength, as more polymer chains are formed and cross-linked.
How does the degree of polymerization affect the strength of resin?
1) There is no correlation between the two
2) Higher degree of polymerization results in increased strength
3) Lower degree of polymerization results in increased strength
4) The strength is unaffected by the degree of polymerization
The maximum allowable creep is 1% for amalgam quality according to the specification.
What is the maximum allowable creep for a 1-day-old amalgam specimen under a 36 MPa stress at 37°C according to ANSI/ADA Specification No. 1 (ISO 24234)?
1) 0.5%
2) 1%
3) 2%
4) 3%
Etching of tooth surface with 37% phosphoric acid creates microporosities in the enamel and dentin. This is the main method of adhesion of composite resin to tooth surface.
After etching the surface energy of the enamel will increase. This will make it very sticky to any kind of contaminants. If salivary contamination will occur, the salivary proteins will precipitate in the microporosities. This will prevent the adequate penetration of the bonding agent, therby reducing the micotag formation. Hence, complete isolation is essential.
Before restoring a tooth with composite, the area is etched. Accidental contamination occurs with saliva, Therefore
1) the area is re-etched before restoration
2) the area is air-dried using an air spray and continue with restoring
3) wipe the saliva with cotton and continue to restore.
4) add excess composie material and cure it
Potassium sulfate acts as an accelerator by increasing the solubility of the hemihydrate and promoting the formation of dihydrate, which speeds up the setting process.
What is the effect of adding potassium sulfate to gypsum-based materials?
1) It accelerates the setting reaction.
2) It retards the setting reaction.
3) It increases the porosity.
4) It has no effect on the setting reaction.
The condensation silicone impression materials are supplied as a base paste and a low-viscosity liquid catalyst (or a paste catalyst).
Putty is a high-viscosity material that has been developed in order to overcome the large polymerization shrinkage of the condensation silicone impression materials.
All the other impression materials are generally supplied as catalyst paste & base paste.
The elastomeric impression material commonly supplied as a base paste & a liquid catalyst is :
1) Polysulfide
2) Condensation silicone
3) Addition silicone
4) Polyether
Ormocers have several advantages, including low shrinkage, excellent biocompatibility, and superior resistance to masticatory forces. These properties make them suitable for restorations that resemble natural teeth.
What are the advantages of using Ormocers in dental restorations?
1) High elasticity and low thermal conductivity.
2) Low shrinkage and excellent biocompatibility.
3) Easy to manipulate and high modulus of elasticity.
4) Good radiopacity and high load deflection rate.
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