MDS PREP
A proximal carious lesion in a radiograph is
1) Usually larger than clinically
2) Smaller than clinically
3) Same as clinically
4) An incipient lesion
Conservative Dentistry
Answer: 2
Proximal carious lesions often appear smaller on radiographs than they are
clinically due to the limitations of radiographic imaging.
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 polishing agent which can be used to polish amalgam restoration is
1) Garnet
2) Emery
3) Silex
4) Alumina
Conservative Dentistry
Answer: 2
Emery is a polishing agent that can be used to polish amalgam restorations. It is a natural abrasive material that is relatively safe for metal surfaces and does not cause significant wear on the amalgam. Garnet, silex, and alumina are also abrasive materials, but they are less commonly used for polishing amalgam due to potential issues with scratching or wearing down the restoration.
Pit and fissure caries can be best pre vented by
1. the use of adhesive sealants
2. topical fluoride application
3. diet control
4. effective plaque control
Conservative Dentistry Answer: 1
1. The use of adhesive sealants: Adhesive sealants are thin, plastic coatings
applied to the chewing surfaces of the back teeth. They fill in the grooves and
depressions, creating a smooth surface that is easier to clean. Sealants act as
a barrier, preventing food and bacteria from lodging in these areas and thus
reducing the risk of tooth decay. This is considered the best preventive measure
because it directly addresses the anatomical vulnerability of the teeth and can
be applied quickly and painlessly.
2. Topical fluoride application: While topical fluoride is beneficial in
preventing dental cavities, it is not as effective as sealants in preventing pit
and fissure caries. Fluoride helps to strengthen the enamel and makes it more
resistant to acid attacks from plaque bacteria. However, because the pits and
fissures are already deep and narrow, fluoride may not always reach these areas
effectively. Sealants, on the other hand, provide a physical barrier that
fluoride cannot always penetrate.
The final polish of a cat gold alloy to achieve a smooth polished surface is done by
1) Pickling
2) Electropolishing
3) Sandblasting
4) Rouge
Conservative Dentistry
Answer: 4
The final polish of a cast gold alloy to achieve a smooth polished surface is
done by
1) Pickling: This is a process used to remove oxides and impurities from the
surface of a metal before applying a final finish. However, it does not provide
the final polish.
2) Electropolishing: This technique uses an electrical current to dissolve the
metal surface and create a smooth finish, but it is not commonly used for gold
alloy restorations.
3) Sandblasting: This method involves propelling an abrasive material against
the metal surface to smooth and clean it, but it is too aggressive for the final
polish of a gold alloy restoration.
4) Rouge: Rouge is a fine abrasive paste used with a polishing wheel or point to
achieve the final polish on a cast gold alloy restoration. It removes minor
imperfections and gives a high luster to the metal.
The correct answer is 4) Rouge, as it is the standard technique for achieving a
smooth, polished surface on cast gold alloys.
During cavity preparation, more incidence of exposure is in
1) Class V cavity in first premolar
2) Class II mesioocclusal cavity
3) Class II distoocclusal cavity
4) Class IV cavity
Conservative Dentistry
Answer: 1
During cavity preparation, the most common area for exposure is a Class V cavity in the first premolar. A Class V cavity is a five-sided cavity that involves the gingival margin of the tooth and the proximal surface. These cavities are particularly prone to exposure because the gingival tissue in this region can be thin, and the proximity to the bone can lead to inadvertent damage during the preparation process.
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 conventional class III amalgam cavity preparation the axial wall in inciso gingival direction should be
1. Straight and parallel to the long axis of the crown, deeper incisally than gingivally
2. Convex and parallel to the long axis of the tooth
3. Concave and parallel to the incisogingival contour of the tooth
4. None of the above
Conservative Dentistry
Answer: 1
Explanation: In a conventional Class III amalgam cavity
preparation, the axial wall should be straight and parallel to the long axis of
the tooth. This design ensures that the restoration has adequate resistance form
and is less likely to dislodge under occlusal forces. The wall being deeper
incisally than gingivally helps to maintain the integrity of the tooth structure
and provides a stable base for the amalgam restoration.