Question

Excessive flare of the distobuccal cavosurface

margin of a Class II amalgam cavity preparation will
result in
A. unsupported enamel at the margin.
B. weak amalgam at the margin.
C. poor retention.
D. poor esthetics

Answer 1

Excessive flare of the distobuccal cavosurface margin of a Class II amalgam cavity preparation leads to unsupported enamel, which can fracture due to its brittleness without underlying support.

Step-by-step explanation:

Excessive flare of the distobuccal cavosurface margin of a Class II amalgam cavity preparation will result in unsupported enamel at the margin. This occurs because the flare creates a thin section of enamel that lacks underlying dentin support. Enamel, while very hard, is brittle and relies on the dentin for strength. Without this support, the enamel can easily fracture under the forces of mastication (chewing). Therefore, a key goal in cavity preparation is to ensure that all enamel at the cavosurface margin is adequately supported by the tooth structure underneath it to prevent future fractures and maintain the integrity of the restoration.