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.
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.
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.
How much fraction of methyl mercuryis absorbed from gut
1)20%
2)50%
3)80%
4)100%
Conservative Dentistry
Answer: 4
100% of methyl mercury is absorbed from the gut. After absorption methyl mercury binds to hemoglobin, circulates systemically and is distributed to all organs, including the brain
Amount of force needed to condense direct filling gold depends on
1. Angle of compaction
2. Surface area of the condenser
3. Amount of the remaining dentin
4. Type of direct filling gold
Conservative Dentistry Answer: 2
Amount of force needed to condense direct filling gold depends on the surface
area of the condenser. The larger the surface area, the less pressure is
required to achieve proper condensation. The force applied affects the
compaction of the gold, but it is the size and shape of the condenser point that
dictate the actual pressure exerted on the material.
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 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.
By doubling the diameter of the condenser point and doubling the force applied, the operator is..............during condensation
1. Applying more pressure
2. Applying less pressure
3. Applying the same pressure
4. Pressure applied is variable
Conservative Dentistry
Answer: 2
By doubling the diameter of the condenser point and doubling the force applied,
the operator is actually applying less pressure during condensation. This is
because pressure is inversely proportional to the area of contact, which is
reduced by doubling the diameter of the condenser point. The increased force is
counteracted by the larger area of contact, resulting in a lower pressure per
unit area.