MDS PREP
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 base of class III preparation is
1) Axial wall
2) Gingival wall
3) Facial wall
4) Lingual wall
Conservative Dentistry
Answer: 1
In a Class III cavity preparation, which typically involves the anterior teeth and is located on the proximal surfaces, the axial wall is considered the base. This wall is oriented parallel to the long axis of the tooth and provides support for the restoration. The gingival wall is also important, but the axial wall is the primary base in this context.
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.
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.
Aluminium oxide polishing powder is obtained from
1) Aluminium
2) Cryolite
3) Bauxite
4) Vulcanite
Conservative Dentistry
Answer: 3
Aluminium oxide (Al₂O₃) is primarily derived from bauxite, which is an ore that contains a high percentage of aluminium. The Bayer process is commonly used to extract aluminium oxide from bauxite.
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.
Main feature of class V amalgam restoration
1. Occlusal wall is greater than gingival wall
2. Retention undercuts placed in the mesial and distal walls
3. Axial wall is flat and does not follow the contours of the tooth
4. Mesial and distal walls converge
Conservative Dentistry
Answer: 1
Explanation: In a Class V amalgam restoration, the occlusal
wall (or the wall facing the occlusal surface) is typically wider than the
gingival wall (the wall facing the gingiva). This design feature helps to
provide adequate bulk for the restoration, ensuring strength and resistance to
fracture. The other options, such as retention undercuts and wall convergence,
are not characteristic features of Class V restorations, which are primarily
concerned with the gingival and occlusal relationships.
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.