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Essentials of Preclinical Conservative Dentistry
(d)
Mandibular first molar:
‘Key-shaped’
preparation (Fig. 9.17)
(e)
Mandibular second molar:
‘Plus-shaped’
preparation (Fig. 9.18)
3.
Aesthetic considerations:
The position of
the tooth in the arch not only dictates the
selection of the restorative material, but also
the design of the tooth preparation so as to
maximise the aesthetic results of the restora-
tion.
4.
Preservation of healthy and vital tooth
structure:
Healthy tooth structure should
not be removed unless justified, as tooth
structure once removed cannot be put back.
5.
Restorative material being used:
This
guides the outline form, for example the
Figure 9.14
Butterfly-shaped preparation on a
maxillary premolar.
Figure 9.15
C-shaped and I-shaped prepara-
tion on a maxillary molar. Note that it does not
involve the oblique ridge.
Figure 9.16
H-shaped preparation on a maxillary
molar involving oblique ridge.
Figure 9.18
Plus-shaped preparation on a man-
dibular second molar.
Figure 9.17
Key-shaped preparation on a man-
dibular first molar .
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