Metal ceramic restoration, ousng

The metal ceramic restoration first became
available commercially during the later 1950s. This
is composed of a metal coping, which fits over the
tooth preparation and ceramic that is fused to the
coping. This is more resistance to fracture than the
first all ceramic restoration [porcelain jacket crown],
because the combination of ceramic and metal
bonded together is stronger than the ceramic alone.
Historically, this was fabricated with metal margins,
and the veneer was limited to visible areas. With
technological advances, the use of porcelain on
occlusal and lingual surfaces has become common.
Several techniques have been developed to obtain
porcelain margins on the labial aspect of the
restoration. A metal collar may be used in posterior
areas in which esthetic appearance is a lesser
issue, whereas the latter technique is common for
teeth in the esthetic zone. Today this restoration
is considered a routine procedure with excellent
clinical performance