NEET MDS Shorts
91614
Conservative Dentistry
The bonding in porcelain fused to metal (PFM) restorations is achieved through a combination of both chemical and mechanical mechanisms.
35827
Conservative DentistryIn 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.
51501
Conservative Dentistry
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.
35990
Conservative DentistryThe process of condensation (compaction) of gold foil in dentistry involves cold-welding layers of gold to build a solid restoration. As the gold is compacted, a phenomenon known as work hardening occurs, which increases the material's hardness and strength.
19030
Conservative DentistryGingivally, 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.
11166
Conservative DentistryExplanation: The external shape of a Class V amalgam restoration is closely related to the contour of the marginal gingiva. This is important for aesthetic and functional reasons, as the restoration must blend seamlessly with the surrounding gingival tissue. The outline form should respect the natural contours to minimize plaque accumulation and promote periodontal health. While axial line angles and the direction of enamel rods are relevant to the preparation, they do not primarily dictate the external shape of the restoration.
64812
Conservative DentistryThe 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.
69097
Conservative Dentistry
A metal ceramic crown preparation on an anterior tooth requires smooth, rounded line angles to ensure proper fit, strength, and aesthetics, and to avoid stress concentrations in the ceramic.
62474
Conservative DentistryThe CAD-CAM system utilizes digital imaging, often through a video camera or scanner, to capture the prepared tooth for designing restorations.
98520
Conservative Dentistry
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.