MDS PREP
When dental bur is sterlized by autoclaving, which of the following chemicals is used for protection of the bur
1) Sodium nitrate
2) Sodium nitrite
3) Silver nitrate
4) Silver nitrite
Conservative Dentistry
Answer: 2
Explanation:Sodium nitrite is often used as a protective agent during the autoclaving process to prevent corrosion of dental instruments, including burs. It helps to maintain the integrity of the metal during the sterilization process.
The CAD-CAM system uses
1) Cadmium in castings
2) A purcelain furnace with very high temperature
3) A video camera to all the prepared tooth
4) None of the above
Conservative Dentistry
Answer: 3
The CAD-CAM system utilizes digital imaging, often through a video camera or
scanner, to capture the prepared tooth for designing restorations.
Gingivally the depth of a class V cavity is
1. 0.5-1 mm
2. 0.75-1 mm
3. 1-1.25 mm
4. 2-3 mm
Conservative Dentistry
Answer: 2
Gingivally, the depth of a class V cavity is typically 0.75-1 mm. This depth is
sufficient to provide a good bond with the tooth structure and prevent
microleakage without causing significant gingival irritation or damage.
In class III composite preparation, retention points should be placed
1. In the axial wall
2. Entirely in dentin
3. At the dentinoenamel junction
4. At the expense of facial and lingual wall
Conservative Dentistry
Answer: 2
Explanation: In Class III composite preparations, retention
points should be placed entirely in dentin. This is because dentin provides a
more reliable substrate for bonding compared to enamel, especially in areas
where the enamel may be thin or compromised. By placing retention points in
dentin, the restoration can achieve better mechanical retention and bonding
strength, which is crucial for the longevity of the restoration.
An old composite restoration is to be replaced. The best method is
1) To remove entire restoration, re-etch and refill
2) To roughen the old restoration, re-etch and refill
3) Composite restoration cannot be replaced or refilled
4) None of the above
Conservative Dentistry
Answer: 2
Roughening the old restoration and re-etching it allows for better bonding of the new composite material.
Annealing of gold foil is the process by which
1. Contaminants are removed from the surface
2. Rigidity decreases and ductility increases
3. Both ductility and propotional limit decrease
4. None of the above
Conservative Dentistry
Answer: 1
Annealing gold foil is the process of heating gold to remove impurities and restore its cohesion properties. Annealing of gold foil is a heat treatment process used to alter the physical and sometimes chemical properties of the material. The primary purpose of annealing gold foil is to remove any contaminants and stresses that may be present on the surface of the material. This is achieved by heating the gold foil to a specific temperature, typically around 400°C (750°F), and then allowing it to cool slowly. The process can also help in improving the foil's ductility, making it more malleable and easier to work with. However, the direct effect of annealing on the rigidity, ductility, and proportional limit is not explicitly stated in the question, and thus the correct answer is that annealing of gold foil primarily serves to remove contaminants from the surface.
Lingual approach to the distal surface in canine for class III amalgam restoration is related to
1. Retention
2. Outline form
3. Resistance
4. Aesthetics
Explanation: The lingual approach to the distal surface of a canine for Class III amalgam restoration is primarily related to aesthetics. This approach minimizes visibility of the restoration from the facial aspect, which is important for maintaining the natural appearance of the tooth. Aesthetic considerations are particularly significant in anterior teeth, where the visibility of restorations can impact the overall smile and facial aesthetics. While retention, outline form, and resistance are important factors in cavity preparation, the lingual approach is specifically chosen to enhance the aesthetic outcome.
The mesial and distal cavity margins for class V gold restoration
1. Should end at the line angles of the tooth
2. Should be converging
3. Should extend into the proximal surfaces
4. All of the above
Conservative Dentistry
Answer: 1
For a class V gold restoration, the mesial and distal cavity margins should end
at the line angles of the tooth to ensure proper adaptation and prevent
overhangs. This is important for both functional and aesthetic reasons