is generally considered to be the most satisfactory extracoronal
restorative material. It has a hardness similar to enamel,
and occlusal and axial contours can easily be built up in
the wax prior to casting. Cast gold alloy restorations include
single and multiple surface inlays. The latter may include
partial or complete coverage (onlays) of the occlusal surface.
Extracoronal gold restorations include full veneer crowns
and three-quarter crowns, in which only one surface of the
tooth (usually the buccal) is left uncovered .
Gold can be used in thin sections but it is not aesthetic.
One millimetre of tooth reduction is required occlusally,
with the exception of the functional cusp bevel where 1.5
mm is necessary. The choice of restoration and preparation
design will depend upon the exact details of each clinical
In situations of severe occlusal stress
• Following endodontic treatment of posterior teeth
• Full or partial coverage of posterior teeth where
there has been significant loss of coronal dentine
• In situations where other materials are not suitable
for establishing proper proximal and/or occlusal contacts
• For restoration of adjacent and/or opposing teeth
to avoid problems arising from use of dissimilar metals.
Evidence of active caries/periodontal disease
• Economic and social factors
• Where patient management requires short visits and
is a brittle material which is liable to fracture in thin
section unless appropriate fit surface treatment is performed
(etching and silanisation) and the restoration is adhesively
luted with a resin-based cement (porcelain veneers and dentine-bonded
ceramic crowns). A minimum margin reduction of 0.8 mm is
required with 1.5–2.0 mm incisally/occlusally. Crown
margins are prepared just below the gingival margin (intracrevicularly)
if aesthetics dictates that this is necessary (Fig. 10.12).
Adequate retention for non-adhesive ceramic crowns depends
on near-parallelism of opposing walls, particularly in the
gingival third of the preparation. Porcelain crowns are
relatively weak restorations and are restricted to anterior
teeth unless a high-strength ceramic (Inceram, Procera,
or Empress II) is used.
Large inadequate restorations on anterior teeth, provided
there is enough tooth substance for a strong preparation
Severely discoloured anterior teeth
Over an existing post and core substructure.
Teeth which do not allow ideal preparation form to support
Teeth with short clinical crowns
When opposing teeth occlude on the cervical fifth of the
jacket crowns are finished to a shoulder or butt
joint margin design unless the preparation is to be bonded
(dentine-bonded crowns). All-ceramic crowns are preferred
to metal ceramic crowns on post-crowned teeth where
there is a risk of trauma. In this case, the weaker porcelain
jacket crown fractures rather than the stress being
transferred via the post core leading to root fracture.
composites with improved strength and wear resistance are
now commercially available and are increasing in popularity.
Coupled with improvements in resinbased luting cements and
dentine bonding systems, indirect composite restorations
(with or without fibre reinforcement) may be considered
appropriate for single unit inlays, onlays and crowns (Fig.
10.13).Laboratory composites are generally preferred to
porcelain restorations for inlays, whereas the latter offer
more permanent form stability in onlay and crown situations.
Some prefer a material which is less wear-resistant and
as such is sacrificial in nature to a highly wear-resistant
ceramic restoration which may ultimately cause excessive
wear of the opposing dentition.
ceramic crown restorations offer a combination of strength
and good aesthetics. Additional tooth preparation (1.5 mm)
is required to allow for both the metal substructure and
metal overlay. These crowns are frequently overcontoured
due to inadequate tooth reduction. Heavy tooth preparation
to achieve adequate thickness for both materials may result
in an increased incidence of pulp death. If this is a risk
then a bevelled shoulder or cervical chamfer may be preferred
to the conventional full 1.5 mm axial reduction in cases
where the tooth preparation has to be extended down onto
root surface or where there is a large pulp. Metal occlusal
coverage is generally preferred to maximise retention and
resistance form and to minimise tooth reduction. Metal occlusal
contacts are easier to create and adjust. Porcelain occlusal
surfaces are more aesthetic but demand additional tooth
reduction and create the risk of excessive occlusal wear
of opposing tooth surfaces.
Anterior teeth where there is insufficient space for an
• Repeated failure of porcelain jacket crowns (identify
• Posterior crowns where aesthetics is important and
full or partial veneer gold crowns are contraindicated on
Where excessive wear of teeth opposing porcelain occlusal
surfaces may be expected. Either a sacrificial indirect
composite approach is preferred or permanent night-time
protection with a Michigan splint may be indicated
• Where pulpal damage risk is high, particularly in
a young patient. Dentine-bonded ceramic crowns have provided
a more conservative viable option in many of these cases.
Crown & Bridge basic
• Restoration Assessment
• Restoration choice
• Tooth preparation