MDS PREP
The product that is formed on the surface of the amalgam restoration and frequently results in discolouration is
1) Sulphide
2) Gamma I phase
3) Gamma II phase
4) Oxide
Conservative Dentistry
Answer: 1
The discoloration of amalgam restorations is often due to the formation of silver sulfide on the surface, which can occur due to the reaction of silver with sulfur compounds in the oral environment. The gamma I phase is a strong component of amalgam, while the gamma II phase is weaker and less stable. Oxides can form as well, but sulfides are more directly associated with the discoloration observed in clinical settings.
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
Which of the following is not recommended in the technique for curing light cured composites?
1) Holding the light tip 1 cm from the tooth
2) Wearing speacial glasses with orange filters
3) Using an exposure duration of 40 to 60 seconds
4) Placing the composite in increments of 1 to 2 mm
Conservative Dentistry Answer: 1
The distance between the tip of the curing light and the tooth is important, as the intensity of the light source is important. A minimum of 400-mW/cm2 is required. It is recommended that the tip be placed as close to the surface to be cured as is physically possible (within 1 to 2mm).
The intensity of light is inverselyproportional to the distance from the source. As a general rule each increment should be at most 1.5 to 2 mm thick. This will ensure complete penetration of the light and maximum curing of thecomposite at the bottom most portion of the cavity preparation.
When punching holes to place a rubber dam for a class V cavity on facial surface
1. Punch holes larger and facially
2. Punch holes smaller and lingually
3. Punch holes larger and lingually
4. Punch holes smaller and facially
Conservative Dentistry
Answer: 1
When punching holes to place a rubber dam for a class V cavity on the facial
surface, punching holes larger and facially provides better access and
visibility. This allows for easier placement and removal of the dam, as well as
less risk of damaging the adjacent tissue
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.
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.
OVERTRITURATION of silver alloy and mercury:
1) reduces contraction
2) increases strength of lathe cut alloy but reduces strength of spherical
3) decreases creep
4) gives a dull crumby mix
overtrituration (i.e., triturating for longer than the recommended time) results in a mix that is warm and has a dull surface; often the mix sticks to the capsule; it shortens setting time (because the amalgam mass becomes heated), increases contraction, and increases creep; also increases tensile and compressive strength values (for lathe-cut alloys), decreases tensile and compressive strengths (for spherical alloys); overtrituration by 10% is acceptable
Upper limit of urinary mercury attributed to extensive amalgam restoration
1) 1 microgram/g of creatinine
2) 3 microgram/g of creatinine
3) 2 microgram/g of creatinine
4) 4 microgram/g of creatinine
Conservative Dentistry
Answer: 4
The upper limit of urinary mercury attributed to extensive amalgam restoration is typically considered to be 4 micrograms/g of creatinine. While the actual limit can vary based on the individual and the extent of amalgam fillings, a level of 4 micrograms/g of creatinine is commonly used as a benchmark for evaluating potential health concerns related to mercury exposure from dental amalgam.