Page 55 - My FlipBook

structing an all porcelain jacket crown. If, on the other hand, less
than the incisal one-half is involved, the condition may be remedied
with less pain and annoyance to the patient by the use of a jacket
partial crown. Such an operation is not indicated unless the tooth can
be prepared in such manner that the remaining stump affords a secure
attachment and permits a sufficient bulk of porcelain to insure strength.

Fig. 5.

hiG. 51.

The approximal walls should converge slightly toward the incisal
edge (Fig. 51), and the shoulders formed by their termination should
run at right angles to the axis of the tooth. The shoulders formed on
the labial and lingual surfaces should run at right angles to the curves
of these surfaces. Enough of these walls should be involved to give
a sufficient bulk of porcelain and to prevent the tip from appearing
bulky and unsightly (Fig. 52).
The approximal walls should be prepared with knife-edge stones,
while the remaining enamel should be removed from the labial and lin-
gual surfaces with flat-face diamond and fissure burs (Fig. 4A and 5B).
After which plug finishing burs and Arkansas stones (Fig. 4B and 5C)
should be used to polish the tooth stump.
In case of extensive erosion on the labial surface and where there
is no decay on the approximal or lingual surfaces, the tooth may be

51