MDS PREP
What are the primary advantages of Ormocers over conventional composites?
1) Outstanding biocompatibility and minimal shrinkage.
2) High elasticity and superior resistance to masticatory forces.
3) Enhanced wear resistance and fluoride release.
4) All of the above.
Ormocers offer several advantages over conventional composites. They have excellent biocompatibility, minimal shrinkage, and their chemical structure allows for high resistance to masticatory forces. Additionally, they are aesthetically pleasing and can be polished to resemble natural teeth.
What is the main advantage of using Ormocers in dental restorations?
1) They have a high coefficient of thermal expansion.
2) They have excellent biocompatibility and resistance to masticatory loading.
3) They are easy to manipulate and require minimal finishing.
4) They can be used in high-stress bearing areas without reinforcement.
The main advantage of using Ormocers is their excellent biocompatibility and resistance to masticatory loading. They also have good esthetic properties, resembling those of natural teeth.
What is the maximum weight loss allowed for a specimen surface according to the specification?
1) 0.04 mg/cm³
2) 0.69 mg/cm²
3) 0.23 mg/cm²
4) There is no maximum weight loss mentioned
The specification mentions that the weight loss must not be greater than 0.04 mg/cm³ from the specimen surface, which is considered negligible from a clinical standpoint.
What are the stoichiometric formulas for the gamma (?), epsilon (?), and zeta (?) phases in dental amalgams?
1) ?: Ag3Sn, ?: Cu3Sn8, ?: Cu3Sn
2) ?: Ag3Sn, ?: AgSn, ?: CuSn
3) ?: AgSn, ?: Cu3Sn, ?: Ag3Sn8
4) ?: AgSn, ?: CuSn, ?: Ag3Sn.
?: Ag3Sn, ?: Cu3Sn8, ?: Cu3Sn
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
A higher degree of polymerization in resins generally correlates with greater strength, as more polymer chains are formed and cross-linked.
What is the typical composition of Resin-Modified Glass Ionomer Cement (RMGI)?
1) Glass ionomer and polyacrylic acid
2) Glass ionomer, HEMA, and tartaric acid
3) Glass ionomer and polycarboxylate acid
4) Glass ionomer and zinc oxide
RMGI contains glass ionomer along with 2-hydroxyethylmethacrylate (HEMA) and tartaric acid to improve its properties.
What is the weakest phase in amalgam and what happens if it is not eliminated or present in sufficient amounts?
1) The y phase is the weakest and is the most susceptible to corrosion.
2) The x phase is the weakest and is the most susceptible to corrosion.
3) The ? phase is the weakest and is the most susceptible to corrosion.
4) The ? phase is the weakest and is the most susceptible to corrosion.
The presence of the y phase makes the amalgam more susceptible to corrosion, and high-copper amalgams are designed to eliminate or significantly reduce this phase.
What is Goldent, and how is it used in dental restorations?
1) A brand of gold alloy used for inlays and onlays
2) A form of gold foil with a high platinum content
3) A combination of powdered gold and gold foil in a pellet form
4) A gold-plated stainless steel mesh used for subgingival retention
Goldent is a form of direct gold restoration where pellets of powdered gold are wrapped in a No. 3 gold foil. The foil acts as a container for the gold particles and allows for better handling and condensation during placement. Each pellet contains approximately 95% powdered gold and 5% gold foil, making it more economical than using gold foil alone for restorations.