MDS PREP
The best method to retract gingiva for class V composite restoration
1. Retraction ford
2. Electrosurgery
3. Rubber dam
4. All of the above
Conservative Dentistry
Answer: 3
For class V composite restoration, the best method to retract gingiva is by
using a rubber dam. This provides isolation, visualization, and moisture
control, which are crucial for successful adhesive techniques. While other
methods like retraction cords or electrosurgery may be used in some cases, they
are not the most suitable for routine class V restorations.
Good supplement to radiographs in diagnosing class III caries clinically is
1) Caries activity tests
2) Examine colour changes below marginal ridges
3) Mirror and explorer
4) Vitality tests
Conservative Dentistry
Answer: 2
To diagnose class III caries clinically, which is caries that involves the proximal surfaces of teeth, a good supplement to radiographs is to examine the proximal surfaces for any color changes, particularly at the contact points where two teeth touch. This is often done using a combination of visual inspection and the use of a dental explorer to detect cavities and softened enamel. However, the answer provided, "Caries activity tests," refers to methods used to assess the activity or inactivity of a caries lesion, not necessarily for diagnosis.
Axial wall in class V cavity in transverse section appears
1. Convex mediodistally and uniformaly placed in the dentin
2. Straight with flat wall
3. Kidney shaped with converging mesial and distal
4. Concave shaped
Conservative Dentistry
Answer: 1
The axial wall in class V cavity in transverse section appears convex
mediodistally and uniformly placed in the dentin. This is because the cavity is
typically shallower in the center and deeper towards the line angles, providing
a good seal and preventing food and plaque accumulation.
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.
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.
The main disadvantages of composites of not being recommended for class II posterior restorations
1. Colour matching is not good
2. Lacks sufficient strength
3. Occlusal wear
4. Frequent fractures at the isthmus
Conservative Dentistry
Answer: 3
One of the main disadvantages of composite materials in Class II posterior restorations is their susceptibility to occlusal wear, which can compromise the longevity of the restoration.
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.
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.